<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Terconazole and can you explain it in depth? [/INST] Terconazole is an antifungal drug used to treat vaginal yeast infection. It comes as a lotion or a suppository and disrupts the biosynthesis of fats in a yeast cell. It has a relatively broad spectrum compared to azole compounds but not triazole compounds. Testing shows that it is a suitable compound for prophylaxis for those that suffer from chronic vulvovaginal candidiasis.

Medical uses
Terconazole is approved to treat vulvovaginal candidiasis (vaginal thrush). It works as a broad spectrum antifungal and has shown to be an effective first-line treatment against other Candida species. It also shows effectiveness against dermatomycoses in animal models.A review found that short-term rates for intravaginally administered azole treatments shows cure in 80% of cases in a short term follow-up and 66% over long term follow-up. In a double-blind study by Slavin in 1992, terconazole showed a 75% mycological cure over a short-term period (7–14 days) and 100% mycological cure over a long-term period (28–34 days). This study focused on the drug as an 80 mg vaginal suppository, taken three times overnight by 10 women. In another placebo-controlled, double blind study by Schmidt et al., the efficacy of different concentrations of terconazole creams were tested. Cream was applied for three days to 24 women between the ages of 18–60. The results showed 0.8% terconazole mycologic cure rates were 83.3% within 1–3 days of starting treatment, 83.3% within 8–11 days of treatment and 58.3% within 30–35 days of treatment. The suppository is more effective after a long-term follow-up than terconazole as a cream or other intravaginal treatments.

Side effects
The most common side effects of terconazole include headaches, vulvar/vaginal irritation, rash, itching, burning or discomfort. Other side effects may include abdominal pain or cramps, dysmenorrhea, chills, fever and allergic reactions. Flu-like symptoms have been recorded in those that take suppositories greater than 160 mg. May cause birth defects if used in the first trimester.Terconazole is not considered hazardous when handled under normal conditions. It is generally non-flammable and non-carcinogenic. Generally is non-toxic, however, can emit toxic fumes when dust is set alight. Can cause respiratory distress as dust. Can be absorbed by embryo within the first trimester of pregnancy and cause birth defects. Cross inhibition shows that there may be some toxicity.

Interactions
Terconazole may interact with the spermicide nonoxynol-9. A precipitate is formed upon combination of both drugs. Terconazole may weaken latex-based condoms.

Chemistry
Terconazole is a triazole ketal with broad-spectrum antifungal/antimycotic tendencies.
Terconazole synthesis synologous with ketoconazole except for the fact that triazole and not imidazole heterocyclic ring is used, and that isopropyl group instead of acetamide.

Terconazole has the chemical formula C26H31Cl2N5O3. The chemical name for terconazole is 1-{[(2S,4S)-2-(2,4-dichlorophenyl)-4-{[p-(4-isopropyl-1-piperazinyl)phenoxy]methyl}-1,3-dioxolan-2-yl]methyl}-1H-1,2,4-triazole. Terconazole has a melting point of 126.3 °C (259.34 °F). The molecular weight of terconazole is 532.462 g/mol. Terconazole is synthesized using two chemical compounds: cis-[2(bromomethyl)-2-(2,4-dichlorophenyl)-1,3-dioxolan-4-yl] methyl benzoate and the sodium salt of triazole, created by mixing triazole with sodium hydride. These are put in a solution and catalyzed using dimethyl sulfate at 1300 °C (2372 °F) to give many different types of triazole derivatives. These are purified using alcohol and chromatography. Terconazole is non-reactive except when exposed to strong oxidizing agents or strong bases due to the nitrogen attached to the triazole ring. It has been found to be photosensitive.

Mechanism of action
Terconazole binds to the heme iron component on the cytochrome P450 enzyme lanosterol of fungi, also known as CYP3A4. The gene ERG11 controls lanosterol creation. Lanosterol is found within the yeast plasma membrane. It is a class of methylsterol. Within a normal yeast cell, lanosterol is demethylated using 14α-demethylation. This process creates zymosterol: a major constituent in the ergosterol biosynthesis pathway for the creation of cell membrane constituents in yeast. This structure provides the membrane with fluidity. This occurs by transforming lanosterol into 4,4-dimethyl cholesta-8,14,24-triene-3-β-ol. This stops respiration by prohibiting reduction of NADH to NAD. This stops biosynthesis of cell membrane products as well as transport and catabolism. Eventually, membrane fluidity and activity of membrane bound enzymes become depleted. It has also been shown to inhibit morphologic change of yeast as well as cell adherence and is directly toxic to yeast. Terconazole targets fungi specifically since humans do not use lanosterol in this pathway. This process does not affect all fungi such as Pneumocystis jirovecii, which lacks lanosterol.

Metabolism
Absorption of terconazole is 5–8% in patients that have had a hysterectomy and 12–16% in other patients. In those that administered 0.8% terconazole, plasma concentrations of the drug remained quite low with the peak plasma concentration being 0.006 mcg at 6.6 hours. Those metabolism rates show similar results in pregnant vulvovaginal candidiasis, non-pregnant vulvovaginal candidiasis and healthy women. The half-life of terconazole in blood is recorded to be around 6.9 hours over a range of 4–11.3 hours). Radioactivity of plasma terconazole is low compared to terconazole at 0.6%. Excretion of radioactivity is via two routes, renal (32–53%) and fecal (47–52%). Metabolism is extensive and is highly protein bound (94.9%) with the degree of binding being independent of drug concentration.

History
In 1940, the first commercial antifungal drug, called amphotericin B, was available on the market, replacing rare and expensive treatments. It was effective in its function but was very toxic and only used for serious infections. The drug was infused into the bloodstream and could cause kidney damage and other side effects </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Tafenoquine and can you explain it in depth? [/INST] Tafenoquine, sold under the brand name Krintafel among others, is a medication used to prevent and to treat malaria. With respect to acute malaria, it is used together with other medications to prevent relapse by Plasmodium vivax. It may be used to prevent all types of malaria. It is taken by mouth.Common side effects include vomiting, headache, and dizziness. Other side effects may include methemoglobinemia, trouble sleeping, and anaphylaxis. In people with G6PD deficiency, red blood cell breakdown may occur. Use in pregnancy is not recommended. Tafenoquine is in the 8-aminoquinoline family of medications. How it works is unclear but it is effective both in the liver and bloodstream. A possible mechanism of action and other novel perspectives have been published.Tafenoquine was approved for medical use in Australia and in the United States in 2018. Tafenoquine is related to primaquine.

Medical use
Prevention
Tafenoquine may be used to prevent all types of malaria. For this use 200 mg 3 days before travel then 200 mg per week until one week after travel is recommended.

Treatment
Tafenoquine is used for eliminating the hypnozoite stage of Plasmodium vivax and Plasmodium ovale that is responsible for relapse of these malarial infections, even when the blood stages are successfully cleared. Primaquine for 14 days can also be used for this </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Desloratadine and can you explain it in depth? [/INST] Desloratadine (trade names Clarinex and Aerius) is a tricyclic H1 inverse agonist that is used to treat allergies.  It is an active metabolite of loratadine.
It was patented in 1984 and came into medical use in 2001.

Medical uses
Desloratadine is used to treat allergic rhinitis,  nasal congestion and chronic idiopathic urticaria (hives).  It is the major metabolite of loratadine and the two drugs are similar in safety and effectiveness. Desloratadine is available in many dosage forms and under many trade names worldwide.An emerging indication for desloratadine is in the treatment of acne, as an inexpensive adjuvant to isotretinoin and possibly as maintenance therapy or monotherapy.

Side effects
The most common side-effects are fatigue (1.2%), dry mouth (3%), and headache (0.6%).

Interactions
Co-administration with erythromycin, ketoconazole, azithromycin, fluoxetine or cimetidine resulted in elevated blood plasma concentrations of desloratadine and its metabolite 3-hydroxydesloratadine in studies. However, no clinically relevant changes were observed.

Pharmacology
Pharmacodynamics
Desloratadine is a selective H1-antihistamine which functions as an inverse agonist at the histamine H1 receptor.At very high doses, is also an antagonist at various subtypes of the muscarinic acetylcholine receptors. This effect is not relevant for the drugs action at therapeutic doses.

Pharmacokinetics
Desloratadine is well absorbed from the gut and reaches highest blood plasma concentrations after about three hours </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Tropicamide and can you explain it in depth? [/INST] Tropicamide, sold under the brand name Mydriacyl among others, is a medication used to dilate the pupil and help with examination of the eye. Specifically it is used to help examine the back of the eye. It is applied as eye drops. Effects occur within 40 minutes and last for up to a day.Common side effects include blurry vision, increased intraocular pressure, and sensitivity to light. Another rare but severe side effect is psychosis, particularly in children. It is unclear if use during pregnancy is safe for the fetus. Tropicamide is in the antimuscarinic part of the anticholinergic family of medications. It works by making the muscles within the eye unable to respond to nerve signals.Tropicamide was approved for medical use in the United States in 1960. It is on the World Health Organizations List of Essential Medicines.

Medical use
Tropicamide is an antimuscarinic drug that produces short acting mydriasis (dilation of the pupil) and cycloplegia when applied as eye drops. It is used to allow better examination of the lens, vitreous humor, and retina. Due to its relatively short duration of effect (4–8 hours), it is typically used during eye examinations such as the dilated fundus examination, but it may also be used before or after eye surgery.  Cycloplegic drops are often also used to treat anterior uveitis, decreasing risk of posterior synechiae and decreasing inflammation in the anterior chamber of the eye.
Tropicamide is occasionally administered in combination with p-hydroxyamphetamine (brand name Paremyd), which is a sympathomimetic </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Guanfacine and can you explain it in depth? [/INST] Guanfacine, sold under the brand name Tenex among others, is an oral medication used to treat attention deficit hyperactivity disorder (ADHD) and high blood pressure. Guanfacine is FDA-approved for monotherapy treatment of ADHD as well as being used for augmentation of other treatments, such as stimulants. Guanfacine is also used off-label to treat tic disorders, anxiety disorders and PTSD.Common side effects include sleepiness, constipation, and dry mouth. Other side effects may include low blood pressure and urinary problems. The FDA has categorized Guanfacine as "Category B"  in pregnancy which means animal-reproduction studies have not demonstrated a fetal risk or an adverse effect during pregnancy or breastfeeding. It appears to work by activating the α2A receptors in the brain thereby decreasing sympathetic nervous system activity.Guanfacine was approved for medical use in the United States in 1986. It is available as a generic medication. In 2019, it was the 140th most commonly prescribed medication in the United States, with more than 4 million prescriptions.

Medical uses
Guanfacine is FDA approved as monotherapy or augmentation with stimulants to treat attention deficit hyperactivity disorder. It is also FDA approved to treat high blood pressure. It is FDA approved as monotherapy treatment for ADHD, and it is also FDA approved to be used in augmentation with stimulant medications when stimulants medications are not fully effective (stimulants include medications such as amphetamines and methylphenidate). Guanfacine can offer a synergistic enhancement of stimulant treatment for ADHD, and in many cases can also help control the side effect profile of stimulant medications.  Guanfacine is also used off-label to treat Tic Disorders, Anxiety Disorders and PTSD.An off-label use of guanfacine is for treatment of anxiety, such as generalized anxiety disorder and post-traumatic stress disorder symptoms. Guanfacine and other α2A agonists have anxiolytic-like action, thereby reducing the emotional responses of the amygdala, and strengthening prefrontal cortical regulation of emotion, action and thought. These actions arise from both inhibition of stress-induced catecholamine release, and from prominent, post-synaptic actions in prefrontal cortex. Due to its prolonged half-life, it also has been seen to improve sleep interrupted by nightmares in PTSD patients. All of these actions likely contribute to the relief of the hyperarousal, re-experiencing of memory, and impulsivity associated with PTSD. Guanfacine appears to be especially helpful in treating children who have been traumatized or abused.

Adverse effects
Side effects of guanfacine are dose-dependent.Very common (>10% incidence) adverse effects include sleepiness, tiredness, headache, and stomach ache.Common (1-10% incidence) adverse effects include decreased appetite, nausea, dry mouth, urinary incontinence, and rashes.Typical side effects such as fatigue, irritability and stomach upset can take a week or two to subside. Increases in dosage can have the same adjustment period.

Interactions
Guanfacine availability is significantly affected by the CYP3A4 and CYP3A5 enzymes. Medications that inhibit or induce those enzymes change the amount of guanfacine in circulation and thus its efficacy and rate of adverse effects. Because of its impact on the heart, it should be used with caution with other cardioactive drugs. Similar concern is appropriate when it is used with sedating medications.Guanfacine is known to lower the users tolerance for alcohol, heightening its effect, and alcohol use may prolong the effects of the medication.

Pharmacology
Guanfacine is a highly selective agonist of the α2A adrenergic receptor, with low affinity for other receptors. However it may also be a potent 5-HT2B receptor agonist, which can be associated with valvulopathy, although not all 5-HT2B agonists have this effect.

Mechanism of action
Guanfacine works by activating α2A adrenoceptors within the central nervous system. This leads to reduced peripheral sympathetic outflow and thus a reduction in peripheral sympathetic tone, which lowers both systolic and diastolic blood pressure.In ADHD, guanfacine works by strengthening regulation of attention and behavior by the prefrontal cortex. These enhancing effects on prefrontal cortical functions are believed to be due to drug stimulation of post-synaptic α2A adrenoceptors on dendritic spines. cAMP-mediated opening of HCN and KCNQ channels is inhibited, which enhances prefrontal cortical synaptic connectivity and neuronal firing. The use of guanfacine for treating prefrontal disorders was developed by the Arnsten Lab at Yale University.

Pharmacokinetics
Guanfacine has an oral bioavailability of 80%. There is no clear evidence of any first-pass metabolism. Elimination half-life is 17 hours with the major elimination route being renal. The principal metabolite is the 3-hydroxy-derivative, with evidence of moderate biotransformation, and the key intermediate is an epoxide. Elimination is not impacted with impaired renal function </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Pegvisomant and can you explain it in depth? [/INST] Pegvisomant, sold under the brand name Somavert, is a growth hormone receptor antagonist used in the treatment of acromegaly </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Pioglitazone/glimepiride and can you explain it in depth? [/INST] Pioglitazone/glimepiride, sold under the brand name Duetact among others, is a fixed-dose combination anti-diabetic medication for the treatment of type 2 diabetes </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Succimer and can you explain it in depth? [/INST] Succimer, sold under the brand name Chemet among others, is a medication used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in a number of types of diagnostic testing. A full course is 19 days of medications by mouth. More than two weeks should pass before a second course is given.Common side effects include vomiting, diarrhea, rash, and low blood neutrophil levels. Liver problems and allergic reactions may also occur with use. Whether use during pregnancy is safe for the baby is unclear. Dimercaptosuccinic acid is in the chelating agent family of medications. It works by binding with lead and a number of other heavy metals, allowing them to leave the body in the urine.Dimercaptosuccinic acid has been used medically since the 1950s. It is on the World Health Organizations List of Essential Medicines. In the United States, no generic version was available as of 2015.

Medical uses
Dimercaptosuccinic acid is indicated for the treatment of lead poisoning in children with blood level measured above 45 µg/dl. The use of dimercaptosuccinic acid is not approved for prevention of lead poisoning in anticipation of exposure in known lead-contaminated environments. Dimercaptosuccinic acid can cross the blood–brain barrier of mice, but it is not known if this is also the case in humans. Even if dimercaptosuccinic acid cannot reverse the damages done to the central nervous system, it might prevent further deterioration.Dimercaptosuccinic acid facilitates urinary excretion of lead, and with sufficiently aggressive treatment, can reduce lead content in the brain. It also increases urinary excretion of copper and zinc. Dimercaptosuccinic acid improved cognitive function in rats that had been exposed to lead, but reduced cognitive function in rats that had not been exposed to lead.7,8-dihydroxyflavone can reverse long-term effects of chronic Lead exposure in the brain.

Chemistry
It is the organosulfur compound with the formula HO2CCH(SH)CH(SH)CO2H.  This colorless solid contains two carboxylic acid and two thiol groups, the latter being responsible for its mildly unpleasant odour.  It occurs in two diastereomers, meso and the chiral dl forms.
The 2,3-dimercaptosuccinic acid molecule has two stereocentres (two asymmetric carbon atoms), and can exist as three different stereoisomers. The 2S,3S and 2R,3R isomers are a pair of enantiomers, whereas the 2R,3S isomer is a meso compound and thus optically inactive.

Preparation and reactivity
Dimercaptosuccinic acid may be prepared by reacting acetylenedicarboxylic acid with sodium thiosulfate or thioacetic acid followed by hydrolysis. The dimethyl ester is also known.Meso 2,3-dimercaptosuccinic acid binds to "soft" heavy metals such as Hg2+ and Pb2+, mobilizing these ions for excretion. It binds to metal cations through the thiol groups, which ionize upon complexation.

History
Dimercaptosuccinic acid was first synthesized by V. Nirenburg in the Urals Polytechnic Institute, commissioned by one of the electrical enterprises of Sverdlovsk, which consumed many tons of mercury and was looking for a medicine to prevent poisoning of personnel. In 1957,  Chinese scientists found that dimercaptosuccinic acid can effectively treat antimony poisoning due to overdose of tartar emetic. Pronounced protective effect in animal poisoning with arsenic and mercury was first shown by I. Okonishnikova in 1962 </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Ruxolitinib and can you explain it in depth? [/INST] Ruxolitinib, sold under the brand names Jakafi and Jakavi, is a medication approved in the US in 2011 for the treatment of intermediate or high-risk myelofibrosis, a type of myeloproliferative disorder that affects the bone marrow; polycythemia vera (PCV), when there has been an inadequate response to or intolerance of hydroxyurea; and steroid-refractory acute graft-versus-host disease. Ruxolitinib is a janus kinase inhibitor.It was developed and marketed by Incyte Corp in the US under the brand name Jakafi, and by Novartis elsewhere in the world, under the brand name Jakavi.

Medical uses
In the United States and the European Union, ruxolitinib is indicated for the treatment of disease-related splenomegaly or symptoms in adults with primary myelofibrosis (also known as chronic idiopathic myelofibrosis), post-polycythaemia-vera myelofibrosis, or post-essential thrombocythaemia myelofibrosis. It is also indicated for the treatment of adults with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Ruxolitinib is also indicated for the treatment of steroid-refractory acute graft-versus-host disease in people who are twelve years of age and older, and for the treatment of chronic graft-versus-host disease (cGVHD) after failure of one or two lines of systemic therapy in people twelve years of age and older.In the United States, ruxolitinib cream is indicated for the topical treatment of mild to moderate atopic dermatitis and vitiligo.

Side effects
In myelofibrosis, the most common side effects include thrombocytopenia (low blood platelet counts), anaemia (low red blood cell counts), neutropenia (low levels of neutrophils), urinary tract infections (infection of the structures that carry urine), bleeding, bruising, weight gain, hypercholesterolaemia (high blood cholesterol levels), dizziness, headache and raised liver enzyme levels.In polycythaemia vera, the most common side effects include anemia (low red blood cell counts) and thrombocytopenia (low blood platelet count), bleeding, bruising,  hypercholesterolaemia (high blood cholesterol levels), hypertriglyceridemia (high blood fat levels), dizziness, raised liver enzyme levels and high blood pressure.In acute graft-versus-host disease, the most common hematologic adverse reactions include anemia, thrombocytopenia, and neutropenia. The most common nonhematologic adverse reactions include infections and edema.Immunologic side effects have included herpes zoster (shingles) and case reports of opportunistic infections. Metabolic side effects have included weight gain. Laboratory abnormalities have included alanine transaminase (ALT) abnormalities, aspartate transaminase (AST) abnormalities, and mildly elevated cholesterol levels.

Mechanism of action
Ruxolitinib is a janus kinase inhibitor (JAK inhibitor) with selectivity for subtypes JAK1 and JAK2.  Ruxolitinib inhibits dysregulated JAK signaling associated with myelofibrosis </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Prochlorperazine and can you explain it in depth? [/INST] Prochlorperazine, formerly sold under the brand name Compazine among others, is a medication used to treat nausea, migraines and anxiety. It is a less preferred medication for anxiety. It may be taken by mouth, rectally, injection into a vein, or injection into a muscle.Common side effects include sleepiness, blurry vision, low blood pressure, and dizziness. Serious side effects may include movement disorders including tardive dyskinesia and neuroleptic malignant syndrome. Use in pregnancy and breastfeeding is generally not recommended. It is a typical antipsychotic which is believed to work by reducing the action of dopamine in the brain.Prochlorperazine was approved for medical use in the United States in 1956. It is available as a generic medication. In 2019, it was the 313th most commonly prescribed medication in the United States, with more than 1 million prescriptions.

Medical uses
Vomiting
Prochlorperazine is used to prevent vomiting caused by chemotherapy, radiation therapy and in the pre- and postoperative setting. A 2015 Cochrane review found no differences in efficacy among drugs commonly used for this purpose in emergency rooms.

Migraine
Prochlorperazine, generally by intravenous, is used to treat migraine. Such use is recommended by The American Headache Society. A 2019 systematic review found prochlorperazine was nearly three times as likely as metoclopramide to relieve headache within 60 minutes of administration.

Labyrinthitis
In the UK prochlorperazine maleate has been used for labyrinthitis, which include not only nausea and vertigo, but spatial and temporal jerking and distortion.

Side effects
Sedation is very common, and extrapyramidal side effects are common and include restlessness, dystonic reactions, pseudoparkinsonism, and akathisia; the extrapyramidal symptoms can affect 2% of people at low doses, whereas higher doses may affect as many as 40% of people.Prochlorperazine can also cause a life-threatening condition called neuroleptic malignant syndrome (NMS). Some symptoms of NMS include high fever, stiff muscles, neck muscle spasm, confusion, irregular pulse or blood pressure, fast heart rate (tachycardia), sweating, abnormal heart rhythms (arrhythmias). Research from the Veterans Administration and United States Food and Drug Administration show injection site reactions. Adverse effects are similar in children.

Warning
The FDA approved label for prochlorperazine includes a warning for increased risk of mortality in elderly patients with dementia related psychosis.

Discontinuation
The British National Formulary recommends a gradual withdrawal when discontinuing antipsychotics to avoid acute withdrawal syndrome or rapid relapse. Symptoms of withdrawal commonly include nausea, vomiting, and loss of appetite. Other symptoms may include restlessness, increased sweating, and trouble sleeping. Less commonly there may be a feeling of the world spinning, numbness, or muscle pains. Symptoms generally resolve after a short period of time.There is tentative evidence that discontinuation of antipsychotics can result in psychosis </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Quinidine and can you explain it in depth? [/INST] Quinidine is a class IA antiarrhythmic agent used to treat heart rhythm disturbances. It is a stereoisomer of antimalarial agent quinine, originally derived from the bark of the cinchona tree. The drug causes increased action potential duration, as well as a prolonged QT interval. As of 2019 its IV formulation is no longer being manufactured for use in the United States.

Medical uses
Quinidine is occasionally used as a class I antiarrhythmic agent to prevent ventricular arrhythmias, particularly in Brugada Syndrome, although its safety in this indication is uncertain.It reduces the recurrence of atrial fibrillation after patients undergo cardioversion, but it has proarrhythmic effects and trials suggest that it may lead to an overall increased mortality in these patients.Quinidine is also used to treat short QT syndrome.Eli Lilly has discontinued manufacture of parenteral quinidine gluconate in the US, and its future availability in many countries is uncertain.

Other uses
There is one study supporting the use of a novel combination of dextromethorphan and low dose quinidine in alleviating symptoms of easy laughing and crying (pseudobulbar affect); these are a type rather severe uncontrollable behaviors which can be present in various neurological pathologies such as amyotrophic lateral sclerosis and multiple sclerosis. The dose of quinidine (10mg two times daily) is about 1/40th of a relatively low antiarrhythmic dose (400mg, twice or 3 times daily, as an example; antiarrhythmic doses can sometimes exceed 1500mg/day). The authors did not observe significant safety risks using the low quinidine dose, but urged caution and also pointed out that quinidine interacts with a large number of other medications in dangerous or unpredictable ways. Interestingly, a meta analysis was published referencing only that one study.Although intravenous quinidine is sometimes used to treat Plasmodium falciparum malaria, the future availability of this agent is uncertain.

Side effects
Quinidine is also an inhibitor of the cytochrome P450 enzyme 2D6, and can lead to increased blood levels of lidocaine, beta blockers, opioids, and some antidepressants. Quinidine also inhibits the transport protein P-glycoprotein and so can cause some peripherally acting drugs such as loperamide to have central nervous system side effects, such as respiratory depression, if the two drugs are coadministered.Quinidine can cause thrombocytopenia, granulomatous hepatitis, myasthenia gravis, and torsades de pointes (dangerous heart rhythm), so is not used much today. Torsades can occur after the first dose. Quinidine-induced thrombocytopenia (low platelet count) is mediated by the immune system, and may lead to thrombocytic purpura.
Quinidine intoxication can lead to a collection of symptoms collectively known as cinchonism, with tinnitus (ringing in the ears) being among the most characteristic and common symptoms of this toxicity syndrome.

Pharmacology
Pharmacodynamics
Quinidine acts as a blocker of voltage-gated sodium channels. Inhibition of the Nav1.5 channel is specifically involved in its antiarrhythmic effects as a class I antiarrhythmic agent. Quinidine also blocks certain voltage-gated potassium channels (e.g., Kv1.4, Kv4.2, hERG, among others), acts as an antimuscarinic and alpha-1 blocker, and is an antimalarial.

Mechanism of action
Like all other class I antiarrhythmic agents, quinidine primarily works by blocking the fast inward sodium current (INa). Quinidines effect on INa is known as a use dependent block. This means at higher heart rates, the block increases, while at lower heart rates, the block decreases. The effect of blocking the fast inward sodium current causes the phase 0 depolarization of the cardiac action potential to decrease (decreased Vmax).
It seems still efficacious as an IV antimalarial against Plasmodium falciparum. This electrolyte dependent agent also increases action potentials and prolongs the QT interval.
Quinidine also blocks the slowly inactivating, tetrodotoxin-sensitive Na current, the slow inward calcium current (ICa), the rapid (IKr) and slow (IKs) components of the delayed potassium rectifier current, the inward potassium rectifier current (IKI), the ATP-sensitive potassium channel (IKATP) and Ito.
At micromolar concentrations, quinidine inhibits Na+/K+-ATPase by binding to the same receptor sites as the digitalis glycosides such as ouabain.
The effect of quinidine on the ion channels is to prolong the cardiac action potential, thereby prolonging the QT interval on the surface ECG.
Other ECG effects include a wide notched P wave, wide QRS complex, depressed ST segment, and U waves. These are the results of both slowed depolarization and repolarization.

Pharmacokinetics
Elimination
The elimination half-life of oral quinidine is 6 to 8 hours, and it is eliminated by the cytochrome P450 system in the liver. About 20% is excreted unchanged via the kidneys.

History
The effects of cinchona bark (the botanical source from which quinidine is extracted) had been commented on long before the understanding of cardiac physiology arose </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Letermovir and can you explain it in depth? [/INST] Letermovir (INN; trade name Prevymis) is an antiviral drug for the treatment of cytomegalovirus (CMV) infections. It has been tested in CMV infected patients with allogeneic stem cell transplants and may also be useful for other patients with a compromised immune system such as those with organ transplants or HIV infections.  The drug was initially developed by the anti-infective division at Bayer, which became AiCuris Anti-infective Cures AG through a spin-out and progressed the development to end of Phase 2 before the project was sold to Merck & Co  for Phase 3 development and approval.The drug was granted fast track status by the US Food and Drug Administration (FDA) and orphan drug status by the European Medicines Agency. It is now approved for prevention of CMV infection and disease in recipients of an allogeneic stem cell transplant.The FDA considers it to be a first-in-class medication.

Medical use
In the US as well as in the EU, letermovir is used for the prevention of cytomegalovirus infection and disease in adult CMV-seropositive recipients of an allogeneic stem cell transplant. The therapy is started shortly after the transplantation and typically lasts for 100 days. Although letermovir is a relatively new antiviral, CMV resistance has been documented in stem cell transplantation recipients; although rare, breakthrough infections of prophylactic treatment with letermovir underscores the ongoing selective pressure on CMVs viral evolution and its continued ability to evade therapeutic suppression through mutations in critical gene regions such as within the UL56 amplicon.

Contraindications
Combining the drug with pimozide or ergot alkaloids (such as ergotamine or methylergometrine) is contraindicated because these drugs are metabolized by the liver enzyme CYP3A4, and letermovir inhibits this enzyme. In people who also take ciclosporin, which increases letermovir concentrations in the body, combination with the cholesterol lowering drugs simvastatin and pitavastatin is also contraindicated. In Canada, this also applies to bosentan, lovastatin and rosuvastatin; and in the EU, to dabigatran, atorvastatin, and rosuvastatin.

Adverse effects
Side effects from the use of letermovir are uncommon, but gastrointestinal symptoms such as gastritis and nausea may occur, as can dyspnea (difficulties breathing) and hepatitis. In general, side effects of the drug are comparable to those under placebo treatment.

Overdose
In studies, giving the threefold therapeutic dose for 14 days resulted in no additional adverse effects. It is unknown whether the substance can be removed from the system by hemodialysis.

Pharmacology
Mechanism of action
Letermovir is a viral terminase inhibitor. It specifically inhibits the CMV viral terminase complex which is encoded by the CMV genes UL56, UL51 and UL89. This inhibition has the effect of preventing cleavage of CMV DNA concatamers, resulting in long uncleaved DNA and noninfectious viral particles. Letermovir is only active against CMV and has no effect on other herpesviruses.

Pharmacokinetics
Letermovir is quickly absorbed from the gut, reaching its highest concentrations in the blood plasma after 1.5 to 3 hours </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Doxepin and can you explain it in depth? [/INST] Doxepin is a medication used to treat major depressive disorder, anxiety disorders, chronic hives, and insomnia. For hives it is a less preferred alternative to antihistamines. It has a mild to moderate benefit for sleeping problems. It is used as a cream for itchiness due to atopic dermatitis or lichen simplex chronicus.Common side effects include sleepiness, dry mouth, constipation, nausea, and blurry vision. Serious side effects may include increased risk of suicide in those under the age of 25, mania, and urinary retention. A withdrawal syndrome may occur if the dose is rapidly decreased. Use during pregnancy and breastfeeding is not generally recommended. Doxepin is a tricyclic antidepressant (TCA). Although how it works for treating depression remains an area of active inquiry, it may involve increasing the levels of norepinephrine, along with blocking histamine, acetylcholine, and serotonin.Doxepin was approved for medical use in the United States in 1969. It is available as a generic medication. In 2017, it was the 240th most commonly prescribed medication in the United States, with more than two million prescriptions.

Medical uses
Doxepin is used as a pill to treat major depressive disorder, anxiety disorders, and chronic hives, and for short-term help with trouble remaining asleep after going to bed (a form of insomnia). As a cream it is used for short-term treatment of itchiness caused by atopic dermatitis or lichen simplex chronicus.

Insomnia
Doxepin is used in the treatment of insomnia. In 2016, the American College of Physicians advised that insomnia be treated first by treating comorbid conditions, then with cognitive behavioral therapy and behavioral changes, and then with drugs; doxepin was among those recommended for short-term help maintaining sleep, on the basis of weak evidence. The 2017 American Academy of Sleep Medicine recommendations focused on treatment with drugs were similar. A 2015 Agency for Healthcare Research and Quality review of treatments for insomnia had similar findings.A major systematic review and network meta-analysis of medications for the treatment of insomnia published in 2022 found that doxepin had an effect size (standardized mean difference (SMD)) against placebo for treatment of insomnia at 4 weeks of 0.30 (95% CI –0.05 to 0.64). The certainty of evidence was rated as very low, and no data were available for longer-term treatment (3 months). For comparison, the other sedating antihistamines assessed, trimipramine and doxylamine, had effect sizes (SMD) at 4 weeks of 0.55 (95% CI –0.11 to 1.21) (very low certainty evidence) and 0.47 (95% CI 0.06 to 0.89) (moderate certainty evidence), respectively. Benzodiazepines and Z-drugs generally showed larger effect sizes (e.g., SMDs of 0.45 to 0.83) than doxepin, whereas the effect sizes of orexin receptor antagonists, such as suvorexant, were more similar (SMDs of 0.23 to 0.44).Doses of doxepin used for sleep normally range from 3 to 6 mg, but high doses of up to 25 to 50 mg may be used as well.

Other uses
A 2010 review found that topical doxepin is useful to treat itchiness.A 2010 review of treatments for chronic hives found that doxepin had been superseded by better drugs but was still sometimes useful as a second-line treatment.

Contraindications
Known contraindications include:
Hypersensitivities to doxepin, other TCAs, or any of the excipients inside the product used
Glaucoma
A predisposition to developing urinary retention such as in benign prostatic hyperplasia
Use of monoamine oxidase inhibitors in last 14 days

Pregnancy and lactation
Its use in pregnant and lactating women is advised against, although the available evidence suggests it is unlikely to cause negative effects on fetal development. The lack of evidence from human studies, however, means it is currently impossible to rule out any risk to the fetus and it is known to cross the placenta. Doxepin is secreted in breast milk and neonatal cases of respiratory depression in association with maternal doxepin use have been reported.

Side effects
Doxepins side effects profile may differ from the list below in some countries where it is licensed to be used in much smaller doses (viz., 3 mg and 6 mg).

Central nervous system: fatigue, dizziness, drowsiness, lightheadedness, confusion, nightmares, agitation, increased anxiety, difficulty sleeping, seizures (infrequently), temporary confusion (delirium), rarely induction of hypomania and schizophrenia (stop medication immediately), extrapyramidal side effects (rarely), abuse in patients with polytoxicomania (rarely), ringing in the ears (tinnitus)
Anticholinergic: dry mouth, constipation, even ileus (rarely), difficulties in urinating, sweating, precipitation of glaucoma
Antiadrenergic: Low blood pressure, (if patient arises too fast from the lying/sitting position to standing—known as orthostatic hypotension), abnormal heart rhythms (e.g., sinus tachycardia, bradycardia, and atrioventricular block)
Allergic/toxic: skin rash, photosensitivity, liver damage of the cholestatic type (rarely), hepatitis (extremely rare), leuko- or thrombocytopenia (rarely), agranulocytosis (very rarely), hypoplastic anemia (rarely)
Others: frequently increased appetite and weight gain, rarely nausea, rarely high blood pressure. May increase or decrease liver function in some people.The side effects of low-dose doxepin for insomnia in long-term clinical trials (28 to 85 days) in adults and elderly people were as follows:

Overdose
Like other TCAs, doxepin is highly toxic in cases of overdose. Mild symptoms include drowsiness, stupor, blurred vision, and excessive dryness of mouth. More serious adverse effects include respiratory depression, hypotension, coma, convulsions, cardiac arrhythmia, and tachycardia. Urinary retention, decreased gastrointestinal motility (paralytic ileus), hyperthermia (or hypothermia), hypertension, dilated pupils, and hyperactive reflexes are other possible symptoms of doxepin overdose. Management of overdose is mostly supportive and symptomatic, and can include the administration of a gastric lavage so as to reduce absorption of the doxepin. Supportive measures to prevent respiratory aspiration is also advisable. Antiarrhythmic agents may be an appropriate measure to treat cardiac arrhythmias resulting from doxepin overdose. Slow intravenous administration of physostigmine may reverse some of the toxic effects of overdose such as anticholinergic effects. Haemodialysis is not recommended due to the high degree of protein binding with doxepin. ECG monitoring is recommended for several days after doxepin overdose due to the potential for cardiac conduction abnormalities.

Interactions
Doxepin should not be used within 14 days of using a monoamine oxidase inhibitor (MAOI) such as phenelzine due to the potential for hypertensive crisis or serotonin syndrome to develop. Its use in those taking potent CYP2D6 inhibitors such as fluoxetine, paroxetine, sertraline, duloxetine, bupropion, and quinidine is recommended against owing to the potential for its accumulation in the absence of full CYP2D6 catalytic activity. Hepatic enzyme inducers such as carbamazepine, phenytoin, and barbiturates are advised against in patients receiving TCAs like doxepin owing to the potential for problematically rapid metabolism of doxepin to occur in these individuals. Sympathomimetic agents may have their effects potentiated by TCAs like doxepin. Doxepin also may potentiate the adverse effects of anticholinergic agents such as benztropine, atropine and hyoscine (scopolamine). Tolazamide, when used in conjunction with doxepin has been associated with a case of severe hypoglycaemia in a type II diabetic individual. Cimetidine may influence the absorption of doxepin. Alcohol may potentiate some of the CNS depressant effects of doxepin. Antihypertensive agents may have their effects mitigated by doxepin. Cotreatment with CNS depressants such as the benzodiazepines can cause additive CNS depression. Co-treatment with thyroid hormones may also increase the potential for adverse reactions.

Pharmacology
Doxepin is a tricyclic antidepressant (TCA). It acts as a serotonin–norepinephrine reuptake inhibitor (SNRI) (a reuptake inhibitor of serotonin and norepinephrine), with additional antiadrenergic, antihistamine, antiserotonergic, and anticholinergic activities.

Pharmacodynamics
Doxepin is a reuptake inhibitor of serotonin and norepinephrine, or a serotonin–norepinephrine reuptake inhibitor (SNRI), and has additional antiadrenergic, antihistamine, antiserotonergic, and anticholinergic activities. It is specifically an antagonist of the histamine H1 and H2 receptors, the serotonin 5-HT2A and 5-HT2C receptors, the α1-adrenergic receptor, and the muscarinic acetylcholine receptors (M1–M5). Similarly to other tricyclic antidepressants, doxepin is often prescribed as an effective alternative to SSRI medications. Doxepin is also a potent blocker of voltage-gated sodium channels, and this action is thought to be involved in both its lethality in overdose and its effectiveness as an analgesic (including in the treatment of neuropathic pain, and as a local anesthetic). The potencies of doxepin in terms of its receptor antagonism specifically are as follows:
Extremely strong: Histamine H1 receptor
Strong: α1-adrenergic receptor, 5-HT2A and muscarinic acetylcholine receptors
Moderate: 5-HT2C and 5-HT1A receptors
Weak: α2-adrenergic and D2 receptorsBased on its IC50 values for monoamine reuptake inhibition, doxepin is relatively selective for the inhibition of norepinephrine reuptake,  with a much weaker effect on the serotonin transporter. Although there is a significant effect that takes place at one of the specific serotonergic binding sites, the 5-HT2A serotonin receptor subtype. There is negligible influence on dopamine reuptake.The major metabolite of doxepin, nordoxepin (desmethyldoxepin), is pharmacologically active similarly, but relative to doxepin, is much more selective as a norepinephrine reuptake inhibitor. In general, the demethylated variants of tertiary amine TCAs like nordoxepin are much more potent inhibitors of norepinephrine reuptake, less potent inhibitors of serotonin reuptake, and less potent in their antiadrenergic, antihistamine, and anticholinergic activities.Antidepressant doses of doxepin are defined as 25 to 300 mg/day, although are typically above 75 mg/day. Antihistamine doses, including for dermatological uses and as a sedative/hypnotic for insomnia, are considered to be 3 to 25 mg, although higher doses between 25 and 50 mg and in some cases even up to 150 mg have been used to treat insomnia. At low doses, below 25 mg, doxepin is a pure antihistamine and has more of a sedative effect. At antidepressant doses of above 75 mg, doxepin is more stimulating with antiadrenergic, antiserotonergic, and anticholinergic effects, and these activities contribute to its side effects.Doxepin is a mixture of (E) and (Z) stereoisomers with an approximate ratio of 85:15. When doxepin was developed, no effort was made to separate or balance the mixture following its synthesis, resulting in the asymmetric ratio. (Z)-Doxepin is more active as an inhibitor of serotonin and norepinephrine reuptake than (E)-doxepin. The selectivity of doxepin for inhibition of norepinephrine reuptake over that of serotonin is likely due to the 85% presence of (E)-doxepin in the mixture. Most other tertiary amine TCAs like amitriptyline and imipramine do not exhibit E-Z isomerism or such mixture asymmetry and are comparatively more balanced inhibitors of serotonin and norepinephrine reuptake.

As a hypnotic
Doxepin is a highly potent antihistamine, with this being its strongest activity. In fact, doxepin has been said to be the most or one of the most potent H1 receptor antagonists available, with one study finding an in vitro Ki of 0.17 nM. It is the most potent and selective H1 receptor antagonist of the TCAs (although the tetracyclic antidepressant (TeCA) mirtazapine is slightly more potent), and other sedating antihistamines, for instance the over-the-counter diphenhydramine (Ki = 16 nM) and doxylamine (Ki = 42 nM), show far lower affinities for this receptor in comparison. The affinity of doxepin for the H1 receptor is far greater than its affinity for other sites, and 10- to 100-fold higher doses are needed for antidepressant effects. In accordance, although it is often described as a "dirty drug" due to its highly promiscuous binding profile, doxepin acts as a highly selective antagonist of the H1 receptor at very low doses (less than 10 mg; typically 3 to 6 mg). At these doses, it notably has no clinically relevant anticholinergic effects such as dry mouth or cognitive/memory impairment, unlike most other sedating antihistamines, and similarly has no effect on other receptors such as adrenergic and serotonin receptors.The H1 receptor antagonism of doxepin is responsible for its hypnotic effects and its effectiveness in the treatment of insomnia at low doses. The incidence of side effects with doxepin and its safety at these doses was similar to that of placebo in clinical trials; the most frequent side effects were headache and somnolence/sedation, both with an incidence of less than 5%. Other side effects sometimes associated with antihistamines, including daytime sedation, increased appetite, and weight gain, all were not observed. Clinical evidence of H1 receptor antagonists and TCAs for the treatment insomnia shows mixed effectiveness and is limited in its quality due to weaknesses like small sample sizes and poor generalizability. However, doxepin is a unique and notable exception; it has been well-studied in the treatment of insomnia and shows consistent benefits with excellent tolerability and safety. Aside from diphenhydramine and doxylamine, which have historical approval as hypnotics, doxepin is the only H1 receptor antagonist that is specifically approved for the treatment of insomnia in the United States.The effect sizes of very low-dose doxepin in the treatment of insomnia range from small to medium. These include subjective and objective measures of sleep maintenance, sleep duration, and sleep efficiency. Conversely, very low-dose doxepin shows relatively weak effects on sleep initiation and does not significantly separate from placebo on this measure. This is in contrast to benzodiazepines and nonbenzodiazepine (Z-drug) hypnotics, which are additionally effective in improving sleep onset latency. However, it is also in contrast to higher doses of doxepin (50 to 300 mg/day), which have been found to significantly reduce latency to sleep onset. A positive dose–response relationship on sleep measures was observed for doses of doxepin between 1 and 6 mg in clinical studies, whereas the incidence of adverse effects remained constant across this dose range in both young and older adults. However, the incidence of adverse effects appeared to increase with longer treatment duration. A dose of doxepin as low as 1 mg/day was found to significantly improve most of the assessed sleep measures, but unlike the 3 and 6 mg/day doses, was not able to improve wake time during sleep. This, along with greater effect sizes with the higher doses, was likely the basis for the approval of the 3 and 6 mg doses of doxepin for insomnia and not the 1 mg dose.At very low doses, doxepin has not shown discontinuation or withdrawal effects nor rebound insomnia. Sustained effectiveness without apparent tolerance was demonstrated in clinical studies of up to 12 weeks duration. This appears to be in contrast to over-the-counter antihistamines like diphenhydramine and doxylamine and all other first-generation antihistamines, which are associated with rapid development of tolerance and dependence (by day 3 or 4 of continuous dosing) and loss of hypnotic effectiveness. It is for this reason that, unlike doxepin, they are not recommended for the chronic management of insomnia and are advised for only short-term treatment (i.e., 1 week). It is not entirely clear why doxepin and first-generation antihistamines are different in this regard, but it has been suggested that it may have to do with the lack of selectivity for the H1 receptor of the latter or may have to do with the use of optimal doses. Unlike very-low-dose doxepin, most first-generation antihistamines also have marked anticholinergic activity as well as associated side effects such as dry mouth, constipation, urinary retention, and confusion. This is particularly true in older people, and antihistamines with concomitant anticholinergic effects are not recommended in adults over the age of 65. Anticholinergic activity notably may interfere with the sleep-promoting effects of H1 receptor blockade.Antagonism of the H1, 5-HT2A, 5-HT2C, and α1-adrenergic receptors is thought to have sleep-promoting effects and to be responsible for the sedative effects of TCAs including those of doxepin. Although doxepin is selective for the H1 receptor at doses lower than 25 mg, blockade of serotonin and adrenergic receptors may also be involved in the hypnotic effects of doxepin at higher doses. However, in contrast to very low doses of doxepin, rebound insomnia and daytime sedation are significantly more frequent than placebo with moderate doses (25 to 50 mg/day) of the drug. In addition, one study found that although such doses of doxepin improved sleep measures initially, most of the benefits were lost with chronic treatment (by 4 weeks). Due to limited data however, more research on potential tolerance and withdrawal effects of moderate doses of doxepin is needed. At these doses of doxepin, dry mouth, an anticholinergic effect, was common (71%), and other side effects such as headache (25%), increased appetite (21%), and dizziness (21%) were also frequently observed, although these adverse effects were notably not significantly more frequent than with placebo in the study in question. In any case, taken together, higher doses of doxepin than very low doses are associated with an increased rate of side effects as well as apparent loss of hypnotic effectiveness with chronic treatment.Doxepin at a dose of 25 mg/day for 3 weeks has been found to decrease cortisol levels by 16% in adults with chronic insomnia and to increase melatonin production by 26% in healthy volunteers. In individuals with neuroendocrine dysregulation in the form of nocturnal melatonin deficiency presumably due to chronic insomnia, very-low-dose doxepin was found to restore melatonin levels to near-normal values after 3 weeks of treatment. These findings suggest that normalization of the hypothalamic–pituitary–adrenal axis and the circadian sleep–wake cycle may be involved in the beneficial effects of doxepin on sleep and insomnia.

CYP2D6 inhibition
Doxepin has been identified as an inhibitor of CYP2D6 in vivo in a study of human patients being treated with 75 to 250 mg/day for depression. While it significantly altered metabolic ratios for sparteine and its metabolites, doxepin did not convert any of the patients to a different metabolizer phenotype (e.g., extensive to intermediate or poor). Nonetheless, inhibition of CYP2D6 by doxepin could be of clinical importance.

Pharmacokinetics
Absorption
Doxepin is well-absorbed from the gastrointestinal tract but between 55 and 87% undergoes first-pass metabolism in the liver, resulting in a mean oral bioavailability of approximately 29%. Following a single very low dose of 6 mg, peak plasma levels of doxepin are 0.854 ng/mL (3.06 nmol/L) at 3 hours without food and 0.951 ng/mL (3.40 nmol/L) at 6 hours with food. Plasma concentrations of doxepin with antidepressant doses are far greater, ranging between 50 and 250 ng/mL (180 to 900 nmol/L). Area-under-curve levels of the drug are increased significantly when it is taken with food.

Distribution
Doxepin is widely distributed throughout the body and is approximately 80% plasma protein-bound, specifically to albumin and α1-acid glycoprotein.

Metabolism
Doxepin is extensively metabolized by the liver via oxidation and N-demethylation. Its metabolism is highly stereoselective. Based on in vitro research, the major enzymes involved in the metabolism of doxepin are the cytochrome P450 enzymes CYP2D6 and CYP2C19, with CYP1A2, CYP2C9, and CYP3A4 also involved to a lesser extent. The major active metabolite of doxepin, nordoxepin, is formed mainly by CYP2C19 (>50% contribution), while CYP1A2 and CYP2C9 are involved to a lesser extent, and CYP2D6 and CYP3A4 are not involved. Both doxepin and nordoxepin are hydroxylated mainly by CYP2D6, and both doxepin and nordoxepin are also transformed into glucuronide conjugates. The elimination half-life of doxepin is about 15–18 hours, whereas that of nordoxepin is around 28–31 hours. Up to 10% of Caucasian individuals show substantially reduced metabolism of doxepin that can result in up to 8-fold elevated plasma concentrations of the drug compared to normal.Nordoxepin is a mixture of (E) and (Z) stereoisomers similarly to doxepin. Whereas pharmaceutical doxepin is supplied in an approximate 85:15 ratio mixture of (E)- and (Z)-stereoisomers and plasma concentrations of doxepin remain roughly the same as this ratio with treatment, plasma levels of the (E)- and (Z)-stereoisomers of nordoxepin, due to stereoselective metabolism of doxepin by cytochrome P450 enzymes, are approximately 1:1.

Elimination
Doxepin is eliminated primarily in the urine and predominantly in the form of glucuronide conjugates, with less than 3% of a dose excreted unchanged as doxepin or nordoxepin.

Pharmacogenetics
Since doxepin is mainly metabolized by CYP2D6, CYP2C9, and CYP2C19, genetic variations within the genes coding for these enzymes can affect its metabolism, leading to changes in the concentrations of the drug in the body. Increased concentrations of doxepin may increase the risk for side effects, including anticholinergic and nervous system adverse effects, while decreased concentrations may reduce the drugs efficacy.
Individuals can be categorized into different types of cytochrome P450 metabolizers depending on which genetic variations they carry. These metabolizer types include poor, intermediate, extensive, and ultrarapid metabolizers. Most people are extensive metabolizers, and have "normal" metabolism of doxepin. Poor and intermediate metabolizers have reduced metabolism of the drug as compared to extensive metabolizers; patients with these metabolizer types may have an increased probability of experiencing side effects. Ultrarapid metabolizers break down doxepin much faster than extensive metabolizers; patients with this metabolizer type may have a greater chance of experiencing pharmacological failure.
A study assessed the metabolism of a single 75 mg oral dose of doxepin in healthy volunteers with genetic polymorphisms in CYP2D6, CYP2C9, and CYP2C19 enzymes. In CYP2D6 extensive, intermediate, and poor metabolizers, the mean clearance rates of (E)-doxepin were 406, 247, and 127 L/hour, respectively (~3-fold difference between extensive and poor). In addition, the bioavailability of (E)-doxepin was about 2-fold lower in extensive relative to poor CYP2D6 metabolizers, indicating a significant role of CYP2D6 in the first-pass metabolism of (E)-doxepin. The clearance of (E)-doxepin in CYP2C9 slow metabolizers was also significantly reduced at 238 L/hour. CYP2C19 was involved in the metabolism of (Z)-doxepin, with clearance rates of 191 L/hour in CYP2C19 extensive metabolizers and 73 L/hour in poor metabolizers (~2.5-fold difference). Area-under-the-curve (0–48 hour) levels of nordoxepin were dependent on the genotype of CYP2D6 with median values of 1.28, 1.35, and 5.28 nM•L/hour in CYP2D6 extensive, intermediate, and poor metabolizers, respectively (~4-fold difference between extensive and poor). Taken together, doxepin metabolism appears to be highly stereoselective, and CYP2D6 genotype has a major influence on the pharmacokinetics of (E)-doxepin. Moreover, CYP2D6 poor metabolizers, as well as patients taking potent CYP2D6 inhibitors (which can potentially convert a CYP2D6 extensive metabolizer into a poor metabolizer), may be at an increased risk for adverse effects of doxepin due to their slower clearance of the drug.Another study assessed doxepin and nordoxepin metabolism in CYP2D6 ultra-rapid, extensive, and poor metabolizers following a single 75 mg oral dose. They found up to more than 10-fold variation in total exposure to doxepin and nordoxepin between the different groups. The researchers suggested that in order to achieve equivalent exposure, based on an average dose of 100%, the dosage of doxepin might be adjusted to 250% in ultra-rapid metabolizers, 150% in extensive metabolizers, 50% in intermediate metabolizers, and 30% in poor metabolizers.

Chemistry
Doxepin is a tricyclic compound, specifically a dibenzoxepin, and possesses three rings fused together with a side chain attached in its chemical structure. It is the only TCA with a dibenzoxepin ring system to have been marketed. Doxepin is a tertiary amine TCA, with its side chain-demethylated metabolite nordoxepin being a secondary amine. Other tertiary amine TCAs include amitriptyline, imipramine, clomipramine, dosulepin (dothiepin), and trimipramine. Doxepin is a mixture of (E) and (Z) stereoisomers (the latter being known as cidoxepin or cis-doxepin) and is used commercially in a ratio of approximately 85:15. The chemical name of doxepin is (E/Z)-3-(dibenzo[b,e]oxepin-11(6H)-ylidene)-N,N-dimethylpropan-1-amine and its free base form has a chemical formula of C19H21NO with a molecular weight of 279.376 g/mol. The drug is used commercially almost exclusively as the hydrochloride salt; the free base has been used rarely. The CAS Registry Number of the free base is 1668-19-5 and of the hydrochloride is 1229-29-4.

History
Doxepin was discovered in Germany in 1963 and was introduced in the United States as an antidepressant in 1969. It was subsequently approved at very low doses in the United States for the treatment of insomnia in 2010.

Society and culture
Generic names
Doxepin is the generic name of the drug in English and German and its INN and BAN, while doxepin hydrochloride is its USAN, USP, BANM, and JAN. Its generic name in Spanish and Italian and its DCIT are doxepina, in French and its DCF are doxépine, and in Latin is doxepinum.The cis or (Z) stereoisomer of doxepin is known as cidoxepin, and this is its INN while cidoxepin hydrochloride is its USAN.

Brand names
It was introduced under the brand names Quitaxon and Aponal by Boehringer and as Sinequan by Pfizer.Doxepin is marketed under many brand names worldwide, including: Adnor, Anten, Antidoxe, Colian, Deptran, Dofu, Doneurin, Dospin, Doxal, Doxepini, Doxesom, Doxiderm, Flake, Gilex, Ichderm, Li Ke Ning, Mareen, Noctaderm, Oxpin, Patoderm, Prudoxin, Qualiquan, Quitaxon, Sagalon, Silenor, Sinepin, Sinequan, Sinquan, and Zonalon. It is also marketed as a combination drug with levomenthol under the brand name Doxure.

Approvals
The oral formulations of doxepin are FDA-approved for the treatment of depression and sleep-maintenance insomnia, and its topical formulations are FDA-approved the short-term management for some itchy skin conditions. In Australia and the United Kingdom, the only licensed indications are in the treatment of major depression and pruritus in eczema.

Research
Antihistamine
Cidoxepin is under development by Elorac, Inc. for the treatment of chronic urticaria (hives) </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Elapegademase and can you explain it in depth? [/INST]  </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Metronidazole and can you explain it in depth? [/INST] Metronidazole, sold under the brand name Flagyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vaginosis. It is effective for dracunculiasis, giardiasis, trichomoniasis, and amebiasis. It is an option for a first episode of mild-to-moderate Clostridium difficile colitis if vancomycin or fidaxomicin is unavailable. Metronidazole is available by mouth, as a cream, and by injection into a vein.Common side effects include nausea, a metallic taste, loss of appetite, and headaches. Occasionally seizures or allergies to the medication may occur. Some state that metronidazole should not be used in early pregnancy, while others state doses for trichomoniasis are safe. Metronidazole is generally considered compatible with breastfeeding.Metronidazole began to be commercially used in 1960 in France. It is on the World Health Organizations List of Essential Medicines. It is available in most areas of the world. In 2019, it was the 138th most commonly prescribed medication in the United States, with more than 4 million prescriptions.

Medical uses
Metronidazole is primarily used to treat: bacterial vaginosis, pelvic inflammatory disease (along with other antibacterials like ceftriaxone), pseudomembranous colitis, aspiration pneumonia, rosacea (topical), fungating wounds (topical), intra-abdominal infections, lung abscess, periodontitis, amoebiasis, oral infections, giardiasis, trichomoniasis, and infections caused by susceptible anaerobic organisms such as Bacteroides, Fusobacterium, Clostridium, Peptostreptococcus, and Prevotella species. It is also often used to eradicate Helicobacter pylori along with other drugs and to prevent infection in people recovering from surgery.Metronidazole is bitter and so the liquid suspension contains metronidazole benzoate. This may require hydrolysis in the gastrointestinal tract and some sources speculate that it may be unsuitable in people with diarrhea or feeding-tubes in the duodenum or jejunum.

Bacterial vaginosis
Drugs of choice for the treatment of bacterial vaginosis include metronidazole and clindamycin. The treatment of choice for bacterial vaginosis in nonpregnant women include metronidazole oral twice daily for seven days, or metronidazole gel intravaginally once daily for five days, or clindamycin intravaginally at bedtime for seven days. For pregnant women, the treatment of choice is metronidazole oral three times a day for seven days. Data does not report routine treatment of male sexual partners.

Trichomoniasis
The 5-nitroimidazole drugs (metronidazole and tinidazole) are the mainstay of treatment for infection with Trichomonas vaginalis. Treatment for both the infected patient and the patients sexual partner is recommended, even if asymptomatic. Therapy other than 5-nitroimidazole drugs is also an option, but cure rates are much lower.

Giardiasis
Oral metronidazole is a treatment option for giardiasis, however, the increasing incidence of nitroimidazole resistance is leading to the increased use of other compound classes.

Dracunculus
In the case of Dracunculus medinensis (Guinea worm), metronidazole just eases worm extraction rather than killing the worm.

C. difficile colitis
Initial antibiotic therapy for less-severe Clostridioides difficile infection colitis (pseudomembranous colitis) consists of metronidazole, vancomycin, or fidaxomicin by mouth. In 2017, the IDSA generally recommended vancomycin and fidaxomicin over metronidazole. Vancomycin by mouth has been shown to be more effective in treating people with severe C. difficile colitis.

E. histolytica
Entamoeba histolytica invasive amebiasis is treated with metronidazole for eradication, in combination with diloxanide to prevent recurrence. Although it is generally a standard treatment it is associated with some side effects.

Preterm births
Metronidazole has also been used in women to prevent preterm birth associated with bacterial vaginosis, amongst other risk factors including the presence of cervicovaginal fetal fibronectin (fFN). Metronidazole was ineffective in preventing preterm delivery in high-risk pregnant women (selected by history and a positive fFN test) and, conversely, the incidence of preterm delivery was found to be higher in women treated with metronidazole.

Hypoxic radiosensitizer
In addition to its anti-biotic properties, attempts were also made to use a possible radiation-sensitizing effect of metronidazole in the context of radiation therapy against hypoxic tumors. However, the neurotoxic side effects occurring at the required dosages have prevented the widespread use of metronidazole as an adjuvant agent in radiation therapy. However, other nitroimidazoles derived from metronidazole such as nimorazole with reduced electron affinity showed less serious neuronal side effects and have found their way into radio-onological practice for head and neck tumors in some countries.

Perioral dermatitis
Canadian Family Physician has recommended topical metronidazole as a third-line treatment for the perioral dermatitis either along with or without oral tetracycline or oral erythromycin as first and second line treatment respectively.

Adverse effects
Common adverse drug reactions (≥1% of those treated with the drug) associated with systemic metronidazole therapy include: nausea, diarrhea, weight loss, abdominal pain, vomiting, headache, dizziness, and metallic taste in the mouth. Intravenous administration is commonly associated with thrombophlebitis. Infrequent adverse effects include: hypersensitivity reactions (rash, itch, flushing, fever), headache, dizziness, vomiting, glossitis, stomatitis, dark urine, and paraesthesia. High doses and long-term systemic treatment with metronidazole are associated with the development of leucopenia, neutropenia, increased risk of peripheral neuropathy, and central nervous system toxicity. Common adverse drug reaction associated with topical metronidazole therapy include local redness, dryness and skin irritation; and eye watering (if applied near eyes). Metronidazole has been associated with cancer in animal studies. In rare cases, it can also cause temporary hearing loss that reverses after cessation of the treatment.Some evidence from studies in rats indicates the possibility it may contribute to serotonin syndrome, although no case reports documenting this have been published to date.

Mutagenesis and carcinogenesis
In 2016 metronidazole was listed by the U.S. National Toxicology Program (NTP) as reasonably anticipated to be a human carcinogen. Although some of the testing methods have been questioned, oral exposure has been shown to cause cancer in experimental animals and has also demonstrated some mutagenic effects in bacterial cultures. The relationship between exposure to metronidazole and human cancer is unclear. One study  found an excess in lung cancer among women (even after adjusting for smoking), while other studies  found either no increased risk, or a statistically insignificant risk.
Metronidazole is listed as a possible carcinogen according to the World Health Organization (WHO) International Agency for Research on Cancer (IARC). A study in those with Crohns disease also found chromosomal abnormalities in circulating lymphocytes in people treated with metronidazole.

Stevens–Johnson syndrome
Metronidazole alone rarely causes Stevens–Johnson syndrome, but is reported to occur at high rates when combined with mebendazole.

Drug interactions
Alcohol
Consuming alcohol while taking metronidazole has been suspected in case reports to cause a disulfiram-like reaction with effects that can include nausea, vomiting, flushing of the skin, tachycardia, and shortness of breath. People are often advised not to drink alcohol during systemic metronidazole therapy and for at least 48 hours after completion of treatment. However, some studies call into question the mechanism of the interaction of alcohol and metronidazole,
and a possible central toxic serotonin reaction for the alcohol intolerance is suggested. Metronidazole is also generally thought to inhibit the liver metabolism of propylene glycol (found in some foods, medicines, and in many electronic cigarette e-liquids), thus propylene glycol may potentially have similar interaction effects with metronidazole.

Other drug interactions
Metronidazole is a moderate CYP2C9 inhibitor. CYP2C9 is an enzyme of cytochrome P450 family. Therefore, metronidazole may interact with medications metabolized by this enzyme. Examples of such medications are lomitapide, warfarin, etc.

Pharmacology
Mechanism of action
Metronidazole is of the nitroimidazole class. It inhibits nucleic acid synthesis by forming nitroso radicals, which disrupt the DNA of microbial cells. This function only occurs when metronidazole is partially reduced, and because this reduction usually happens only in anaerobic bacteria and protozoans, it has relatively little effect upon human cells or aerobic bacteria.

Pharmacokinetics
Oral metronidazole is approximately 80% bioavailable via the gut and peak blood plasma concentrations occur after one to two hours. Food may slow down absorption but does not diminish it. Of the circulating substance, about 20% is bound to plasma proteins. It penetrates well into tissues, the cerebrospinal fluid, the amniotic fluid and breast milk, as well as into abscess cavities.About 60% of the metronidazole is metabolized by oxidation to the main metabolite hydroxymetronidazole and a carboxylic acid derivative, and by glucuronidation. The metabolites show antibiotic and antiprotozoal activity in vitro. Metronidazole and its metabolites are mainly excreted via the kidneys (77%) and to a lesser extent via the faeces (14%). The biological half-life of metronidazole in healthy adults is eight hours, in infants during the first two months of their lives about 23 hours, and in premature babies up to 100 hours.The biological activity of hydroxymetronidazole is 30% to 65%, and the elimination half-life is longer than that of the parent compound. The serum half-life of hydroxymetronidazole after suppository was 10 hours, 19 hours after intravenous infusion, and 11 hours after a tablet.

History
The drug was initially developed by Rhône-Poulenc in the 1950s and licensed to G.D. Searle. Searle was acquired by Pfizer in 2003. The original patent expired in 1982, but evergreening reformulation occurred thereafter.

Brand name
In India, it is sold under the brand name Metrogyl and Flagyl. In Bangladesh, it is available as Amodis, Amotrex, Dirozyl, Filmet, Flagyl, Flamyd, Metra, Metrodol, Metryl, etc. In Pakistan, it is sold under the brand name of Flagyl and Metrozine.

Synthesis
2-Methylimidazole (1) may be prepared via the Debus-Radziszewski imidazole synthesis, or from ethylenediamine and acetic acid, followed by treatment with lime, then Raney nickel. 2-Methylimidazole is nitrated to give 2-methyl-4(5)-nitroimidazole (2), which is in turn alkylated with ethylene oxide or 2-chloroethanol to give metronidazole (3):

Veterinary use
Metronidazole is used to treat infections of Giardia in dogs, cats, and other companion animals, although it does not reliably clear infection with this organism and is being supplanted by fenbendazole for this purpose in dogs and cats </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Macimorelin and can you explain it in depth? [/INST] Macimorelin (INN) – or Macrilen (trade name) – is a drug that was developed by Æterna Zentaris for use in the diagnosis of adult growth hormone deficiency. Macimorelin acetate, the salt formulation, is a synthetic growth hormone secretagogue receptor agonist. It is a growth hormone secretagogue receptor (ghrelin receptor) agonist causing release of growth hormone from the pituitary gland.Macimorelin acetate is described chemically as D-Tryptophanamide, 2-methylalanyl-N-[(1R)-1-(formylamino)-2-(1H-indol-3-yl)ethyl]-acetate.
Macimorelin (Macrilen™) was invented and first synthesized by the research group of Professor Martinez at University of Montpellier, Centre National de la Recherche Scientitifique (CNRS), France. This transpired from a long-lasting research collaboration with Aeterna Zentaris. Aeterna Zentaris later in-licensed macimorelin as a development candidate from the CNRS and proceeded with the pre-clinical and clinical development of the compound.
As of January 2014, it was in Phase III clinical trials </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Metoclopramide and can you explain it in depth? [/INST] Metoclopramide is a medication used for stomach and esophageal problems. It is commonly used to treat and prevent nausea and vomiting, to help with emptying of the stomach in people with delayed stomach emptying, and to help with gastroesophageal reflux disease. It is also used to treat migraine headaches.Common side effects include: feeling tired, diarrhea, and feeling restless. More serious side effects include: movement disorder like tardive dyskinesia, a condition called neuroleptic malignant syndrome, and depression. It is thus rarely recommended that people take the medication for longer than twelve weeks. No evidence of harm has been found after being taken by many pregnant women. It belongs to the group of medications known as dopamine-receptor antagonists and works as a prokinetic.In 2012, metoclopramide was one of the top 100 most prescribed medications in the United States. It is available as a generic medication. It is on the World Health Organizations List of Essential Medicines. In 2017, it was the 253rd most commonly prescribed medication in the United States, with more than one million prescriptions.

Medical uses
Nausea
Metoclopramide is commonly used to treat nausea and vomiting associated with conditions such as uremia, radiation sickness, cancer and the effects of chemotherapy, labor, infection, and emetogenic drugs. As a perioperative anti-emetic, the effective dose is usually 25 to 50 mg (compared to the usual 10 mg dose).
It is also used in pregnancy as a second choice for treatment of hyperemesis gravidarum (severe nausea and vomiting of pregnancy).It is also used preventatively by some EMS providers when transporting people who are conscious and spinally immobilized.

Migraine
In migraine headaches, metoclopramide may be used in combination with paracetamol (acetaminophen) or in combination with aspirin.

Gastroparesis
Evidence also supports its use for gastroparesis, a condition that causes the stomach to empty poorly, and as of 2010 it was the only drug approved by the FDA for that condition.It is also used in gastroesophageal reflux disease.

Lactation
While metoclopramide is used to try to increase breast milk production, evidence for its effectiveness for this is poor. Its safety for this use is also unclear.

Procedures
Intravenous metoclopramide is used in small-bowel follow-through, small-bowel enema, and radionuclide gastric-emptying studies to reduce the time taken for barium to go through the intestines, thus reducing the total time needed for the procedures. Metoclopramide also prevents vomiting after oral ingestion of barium.

Contraindications
Metoclopramide is contraindicated in pheochromocytoma. It should be used with caution in Parkinsons disease since, as a dopamine antagonist, it may worsen symptoms. Long-term use should be avoided in people with clinical depression, as it may worsen ones mental state. It is contraindicated for people with a suspected bowel obstruction, in epilepsy, if a stomach operation has been performed in the previous three or four days, if the person has ever had bleeding, perforation or blockage of the stomach, and in newborn babies.The safety of the drug was reviewed by the European Medicines Agency in 2011, which determined that it should not be prescribed in high doses, for periods of more than five days, or given to children below 1 year of age. They suggested its use in older children should be restricted to treating post-chemotherapy or post-surgery nausea and vomiting, and even then only for patients where other treatments have failed. For adults, they recommended its use be restricted to treating migraines and post-chemotherapy or post-surgery patients.

Pregnancy
Metoclopramide has long been used in all stages of pregnancy with no evidence of harm to the mother or foetus. A large cohort study of babies born to Israeli women exposed to metoclopramide during pregnancy found no evidence that the drug increases the risk of congenital malformations, low birth weight, preterm birth, or perinatal mortality. A large cohort study in Denmark found, in addition, no association between metoclopramide exposure and miscarriage. Metoclopramide is excreted into milk.

Infants
A systematic review found a wide range of reported outcomes for treatment of gastroesophageal reflux disease (GERD) in infants and concluded a "poor" rating of evidence and "inconclusive" rating of safety and efficacy for the treatment of GERD in infants.

Side effects
Common adverse drug reactions (ADRs) associated with metoclopramide therapy include restlessness (akathisia), and focal dystonia. Infrequent ADRs include hypertension, hypotension, hyperprolactinaemia leading to galactorrhea, headache, and extrapyramidal effects such as oculogyric crisis.Metoclopramide may be the most common cause of drug-induced movement disorders. The risk of extrapyramidal effects is increased in people under 20 years of age, and with high-dose or prolonged therapy. Tardive dyskinesia may be persistent and irreversible in some people. The majority of reports of tardive dyskinesia occur in people who have used metoclopramide for more than three months. Consequently, the US Food and Drug Administration (FDA) recommends that metoclopramide be used for short-term treatment, preferably less than 12 weeks. In 2009, the FDA required all manufacturers of metoclopramide to issue a black box warning regarding the risk of tardive dyskinesia with chronic or high-dose use of the drug.Dystonic reactions may be treated with benzatropine, diphenhydramine, trihexyphenidyl, or procyclidine. Symptoms usually subside with diphenhydramine injected intramuscularly. Agents in the benzodiazepine class of drugs may be helpful, but benefits are usually modest and side effects of sedation and weakness can be problematic.In some cases, the akathisia effects of metoclopramide are directly related to the infusion rate when the drug is administered intravenously. Side effects were usually seen in the first 15 min after the dose of metoclopramide.

Rare side effects
Diabetes, age, and female gender are risk factors that  increase  the  likelihood  of  experiencing  a  neuropsychiatric side effect of metoclopramide.
Panic disorder
Major depressive disorder
Agoraphobia
Agranulocytosis, supraventricular tachycardia, hyperaldosteronism, neuroleptic malignant syndrome, akathisia and tardive dyskinesia.
Methaemoglobinaemia*

Pharmacology
Pharmacodynamics
Metoclopramide appears to bind to dopamine D2 receptors with nanomolar affinity (Ki = 28.8 nM), where it is a receptor antagonist, and is also a mixed 5-HT3 receptor antagonist/5-HT4 receptor agonist.

Mechanism of action
The antiemetic action of metoclopramide is due to its antagonist activity at D2 receptors in the chemoreceptor trigger zone  in the central nervous system — this action prevents nausea and vomiting triggered by most stimuli. At higher doses, 5-HT3 antagonist activity may also contribute to the antiemetic effect.The gastroprokinetic activity of metoclopramide is mediated by muscarinic activity, D2 receptor antagonist activity, and 5-HT4 receptor agonist activity. The gastroprokinetic effect itself may also contribute to the antiemetic effect. Metoclopramide also increases the tone of the lower esophageal sphincter.Metoclopramide might influence on mood because of its blockade action on 5-HT4 and 5-HT3.

Chemistry
Metoclopramide is a substituted benzamide; cisapride and mosapride are structurally related.

History
Metoclopramide was first described by Louis Justin-Besançon and Charles Laville in 1964, while working to improve the anti-dysrhythmic properties of procainamide. That research project also produced the product sulpiride. The first clinical trials were published by Tourneu et al. in 1964 and by Boisson and Albot in 1966. Justin-Besançon and Laville worked for Laboratoires Delagrange and that company introduced the drug as Primperan in 1964. Laboratoires Delagrange was acquired by Synthelabo in 1991 which eventually became part of Sanofi.A.H. Robins introduced the drug in the US under the brand name Reglan in 1979 as an injectable and an oral form was approved in 1980. in 1989 A.H. Robins was acquired by American Home Products, which changed its name to Wyeth in 2002.The drugs were initially used to control nausea for people with severe headaches or migraines, and later uses for nausea caused by radiation therapy and chemotherapy, and later yet for treating nausea caused by anesthesia. In the US the injectable form was labelled for chemotherapy-induced nausea and the oral form was eventually labelled for gastroesophageal reflux disease.It became widely used in the 1980s, becoming the most commonly used drug to treat anesthesia-induced nausea and for treating gastritis in emergency rooms.The first generics were introduced in 1985.In the early 1980s signs began to emerge in pharmacovigilance studies from Sweden that the drug was causing tardive dyskinesia in some patients. The FDA required a warning about tardive dyskinesia to be added to the drug label in 1985 stating that: "tardive dyskinesia . . . may develop in patients treated with metoclopramide,” and warned against use longer than 12 weeks, as that was how long the drug has been tested. In 2009 the FDA required that a black box warning be added to the label.The emergence of this severe side effect led to a wave of product liability litigation against generic manufacturers as well as Wyeth. The litigation was complicated since there was a lack of clarity in jurisdiction between state laws, where product liability is determined, and federal law, which determines how drugs are labelled, as well as between generics companies, which had no control over labelling, and the originator company, which did. The litigation yielded at least two important cases. In Conte v. Wyeth in the California state courts, the claims of the plaintiff against the generic companies Pliva, Teva, and Purepac that had sold the drugs that the plaintiff actually took, and the claims against Wyeth, whose product the plaintiff never took, were all dismissed by the trial court, but the case was appealed, and in 2008 the appellate court upheld the dismissal of the cases against the generic companies, but reversed on Wyeth, allowing the case against Wyeth to proceed. This established an "innovator liability" or "pioneer liability" for pharmaceutical companies. The precedent was not widely followed in California nor in other states. Litigation over the same issues related to metoclopramide also reached the US Supreme Court in PLIVA, Inc </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Anastrozole and can you explain it in depth? [/INST] Anastrozole, sold under the brand name Arimidex among others, is a medication used in addition to other treatments for breast cancer. Specifically it is used for hormone receptor-positive breast cancer. It has also been used to prevent breast cancer in those at high risk. It is taken by mouth.Common side effects of anastrozole include hot flashes, altered mood, joint pain, and nausea. Severe side effects include an increased risk of heart disease and osteoporosis. Use during pregnancy may harm the baby. Anastrozole is in the aromatase-inhibiting family of medications.  It works by blocking the production of estrogens in the body, and hence has antiestrogenic effects.Anastrozole was patented in 1987 and was approved for medical use in 1995. It is on the World Health Organizations List of Essential Medicines. Anastrozole is available as a generic medication. In 2019, it was the 176th most commonly prescribed medication in the United States, with more than 3 million prescriptions.

Medical uses
Breast cancer
Anastrozole is used in the treatment and prevention of breast cancer in women. The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial was of localized breast cancer and women received either anastrozole, the selective estrogen receptor modulator tamoxifen, or both for five years, followed by five years of follow-up. After more than 5 years the group that received anastrozole had better results than the tamoxifen group. The trial suggested that anastrozole is the preferred medical therapy for postmenopausal women with localized estrogen receptor-positive breast cancer.

Early puberty
Anastrozole is used at a dosage of 0.5 to 1 mg/day in combination with the antiandrogen bicalutamide in the treatment of peripheral precocious puberty, for instance due to familial male-limited precocious puberty (testotoxicosis) and McCune–Albright syndrome, in boys.

Available forms
Anastrozole is available in the form of 1 mg oral tablets. No alternative forms or routes are available.

Contraindications
Contraindications of anastrozole include hypersensitivity to anastrozole or any other component of anastrozole formulations, pregnancy, and breastfeeding. Hypersensitivity reactions to anastrozole including anaphylaxis, angioedema, and urticaria have been observed.

Side effects
Common side effects of anastrozole (≥10% incidence) include hot flashes,
asthenia, arthritis, pain, arthralgia, hypertension, depression, nausea and vomiting, rash, osteoporosis, bone fractures, back pain, insomnia, headache, bone pain, peripheral edema, coughing, dyspnea, pharyngitis, and lymphedema. Serious but rare adverse effects (<0.1% incidence) include skin reactions such as lesions, ulcers, or blisters; allergic reactions with swelling of the face, lips, tongue, and/or throat that may cause difficulty swallowing or breathing; and abnormal liver function tests as well as hepatitis.

Interactions
Anastrozole is thought to have clinically negligible inhibitory effects on the cytochrome P450 enzymes CYP1A2, CYP2A6, CYP2D6, CYP2C8, CYP2C9, and CYP2C19. As a result, it is thought that drug interactions of anastrozole with cytochrome P450 substrates are unlikely. No clinically significant drug interactions have been reported with anastrozole as of 2003.Anastrozole does not affect circulating levels of tamoxifen or its major metabolite N-desmethyltamoxifen. However, tamoxifen has been found to decrease steady-state area-under-the-curve levels of anastrozole by 27%. But estradiol levels were not significantly different in the group that received both anastrozole and tamoxifen compared to the anastrozole alone group, so the decrease in anastrozole levels is not thought to be clinically important.

Pharmacology
Pharmacodynamics
Anastrozole works by reversibly binding to the aromatase enzyme, and through competitive inhibition blocks the conversion of androgens to estrogens in peripheral (extragonadal) tissues. The medication has been found to achieve 96.7% to 97.3% inhibition of aromatase at a dosage of 1 mg/day and 98.1% inhibition of aromatase at a dosage of 10 mg/day in humans. As such, 1 mg/day is considered to be the minimal dosage required to achieve maximal suppression of aromatase with anastrozole. This decrease in aromatase activity results in an at least 85% decrease in estradiol levels in postmenopausal women. Levels of corticosteroids and other adrenal steroids are unaffected by anastrozole.

Pharmacokinetics
The bioavailability of anastrozole in humans is unknown, but it was found to be well-absorbed in animals. Absorption of anastrozole is linear over a dosage range of 1 to 20 mg/day in humans and does not change with repeated administration. Food does not significantly influence the extent of absorption of anastrozole. Peak levels of anastrozole occur a median 3 hours after administration, but with a wide range of 2 to 12 hours. Steady-state levels of anastrozole are achieved within 7 to 10 days of continuous administration, with 3.5-fold accumulation. However, maximal suppression of estradiol levels occurs within 3 or 4 days of therapy.Active efflux of anastrozole by P-glycoprotein at the blood–brain barrier has been found to limit the central nervous system penetration of anastrozole in rodents, whereas this was not the case with letrozole and vorozole. As such, anastrozole may have peripheral selectivity in humans, although this has yet to be confirmed. In any case, estradiol is synthesized peripherally and readily crosses the blood–brain barrier, so anastrozole would still expected to reduce estradiol levels in the central nervous system to a certain degree. The plasma protein binding of anastrozole is 40%.The metabolism of anastrozole is by N-dealkylation, hydroxylation, and glucuronidation. Inhibition of aromatase is due to anastrozole itself rather than to metabolites, with the major circulating metabolite being inactive. The elimination half-life of anastrozole is 40 to 50 hours (1.7 to 2.1 days) </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Asciminib and can you explain it in depth? [/INST] Asciminib, sold under the brand name Scemblix, is a medication used to treat Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML). Asciminib is a protein kinase inhibitor.The most common adverse reactions include upper respiratory tract infections, musculoskeletal pain, fatigue, nausea, rash, and diarrhea.Asciminib was approved for medical use in the United States in October 2021, and in the European Union in August 2022.The U.S. Food and Drug Administration (FDA) granted the application for asciminib priority review, fast track, orphan drug, and breakthrough therapy designations.

Mechanism of action
Asciminib is described as a "STAMP inhibitor," which means "specifically targeting the ABL myristoyl pocket." The wild-type ABL has a myristoylated N-terminus, which binds to an allosteric site, but the ABL fusion protein does not have the myristoylated domain. In the wild-type protein, when myristoylated N-terminus binds to the allosteric site, the kinase has reduced activity. Since the mutant fusion protein does not have the myristoylated N-terminus domain, it is not subject to this form of regulation, and thus the fusion protein is constitutively active. Asciminib binds to the allosteric site, resulting in an inhibition of bcr-abl activity.Unlike other bcr-abl inhibitors, such as imatinib, asciminib does not bind to the ATP-binding site on the active site of the enzyme. Asciminib and active site bcr-abl inhibitors have non-overlapping resistance mutations. The mutations A337V and P223S overcome the inhibitory activity of asciminib, but asciminib is not affected by the notorious T315I mutation that affects most ATP-competitive active site inhibitors, except ponatinib.

Adverse effects
Common side effects of Asciminib are symptoms of a cold, muscle pain, joint pain, bone pain, fatigue, nausea, diarrhea, rash as well as the patient displaying abnormal blood tests </s>