What is it used for?
- High blood pressure (hypertension).
- Heart failure.
- Fluid retention (ascites and oedema) in liver cirrhosis.
How does it work?
Amiloride tablets and oral solution contain the active ingredient amiloride, which is a type of medicine called a potassium-sparing diuretic. (Diuretics are sometimes referred to as 'water tablets').
Diuretics work by causing the kidneys to increase the amount of salts such as sodium that are filtered out of the blood and into the urine. When these salts are filtered out of the blood by the kidneys, water is also drawn alongside. As diuretics increase the removal of salts from the blood, they also cause more water to be drawn out of the blood and into the urine.
Removing water from the blood decreases the volume of fluid circulating through the blood vessels. This subsequently decreases the pressure within the blood vessels. Diuretics are therefore used to lower high blood pressure.
As diuretics remove fluid from the body, they are also used to treat conditions where excess fluid has been retained in the body (oedema). In heart failure for example, fluid can accumulate in the lungs, causing shortness of breath. Diuretics are used to help the body remove this excess fluid and therefore relieve the symptoms of heart failure. The decreased pressure in the blood vessels caused by the diuretic also decreases the effort required by the heart to pump blood around the body, which is useful in heart failure where the pumping mechanism of the heart is less effective.
Diuretics can also be used to remove the excess fluid that can accumulate in people with cirrhosis of the liver. This fluid may accumulate in the abdomen (ascites) or in the legs (oedema).
Amiloride has a weak diuretic effect when used on its own, hence it is usually used in combination with other diuretics. Most other diuretics cause the amount of potassium in the blood to drop. Amiloride doesn't have this effect, as it is a 'potassium-sparing' diuretic. It is usually added to diuretic treatment to prevent excessive amounts of potassium from being lost.
How do I take it?
- Amiloride can be taken either with or without food.
- The dose to be taken daily will vary depending on your symptoms. Follow the instructions given by your doctor.
- As diuretics cause your kidneys to produce more urine, you may find that if you take a dose too late in the day that you need to get up in the night to visit the toilet. For this reason, it is recommended that you take this medicine in the morning. Seek further advice from your doctor or pharmacist.
- This medicine may cause fatigue and dizziness. You should take care when performing potentially hazardous activities, such as driving or operating machinery, until you know how this medicine affects you and are sure you can perform such activities safely.
- This medicine can cause the amount of potassium in your bloodstream to increase. For this reason you should avoid consuming large amounts of foods that have a high potassium content, for example dried fruit, bananas, tomatoes and 'low sodium' salt, while you are taking the medicine. You should also avoid potassium supplements.
- While taking this medicine you may need to have regular blood tests to monitor your kidney function and the levels of salts such as potassium and sodium in your blood.
- If you experience any of the following symptoms while taking this medicine you should inform your doctor promptly, so that the amount of fluids and salts in your body can be checked: thirst, lethargy, confusion, weakness, drowsiness, muscle cramps, scanty production of urine, abnormal heart rhythm, seizures, nausea and vomiting.
Use with caution in
- Elderly people.
- Decreased liver function.
- Decreased kidney function.
- People with a high level of uric acid in their blood (hyperuricaemia).
- People with an increase in the acidity of the blood (metabolic acidosis).
Not to be used in
- People whose kidneys are not producing urine.
- Kidney failure.
- Diabetic kidney disease (nephropathy).
- People with a high level of potassium in their blood (hyperkalaemia).
- Addison's disease.
- Children or adolescents under 18 years of age.
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine should not normally be used during pregnancy, unless considered essential by your doctor. The expected benefit to the mother must be greater than the possible risks to the developing baby. Seek further medical advice from your doctor.
- It is not known if this medicine passes into breast milk. It is not recommended for women who are breastfeeding. Seek further medical advice from your doctor.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting, abdominal pain, indigestion or wind.
- Dry mouth.
- Loss of appetite.
- Weakness or fatigue.
- Increased amount of potassium in the blood (hyperkalaemia).
- Increased thirst.
- Abnormal heart beats (arrhythmias).
- A drop in blood pressure that occurs when going from lying down to sitting or standing, which results in dizziness and lightheadedness (postural hypotension).
- Awareness of your heart beat (palpitations).
- Shortness of breath.
- Nasal congestion.
- Chest pain.
- Sensation of pins and needles.
- Muscle cramps.
- Bleeding in the gut.
- Decreased amount of sodium in the blood (hyponatraemia).
- Visual disturbances.
- Sensation of ringing or other noise in the ears (tinnitus).
- Decreased sex drive and erectile dysfunction (impotence).
- Increased need to pass urine.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
This medicine is likely to have an additive effect with other medicines that decrease blood pressure, particularly medicines that are used to treat high blood pressure (antihypertensives). This may cause dizziness, which can usually be relieved by lying down until the symptoms pass. If you feel dizzy while taking this medicine in combination with other medicines that can lower blood pressure you should let your doctor know, as your doses may need adjusting. Other medicines that decrease blood pressure include the following:
- ACE inhibitors, eg enalapril
- alpha-blockers such as prazosin
- angiotensin II receptor antagonists such as losartan
- antipsychotics such as chlorpromazine
- benzodiazepines, eg temazepam, diazepam
- beta-blockers such as propranolol
- calcium-channel blockers such as verapamil, nifedipine
- other diuretics, eg furosemide (if this medicine is used with other diuretics there may also be a greater chance of the level of sodium in your blood falling too low)
- dopamine agonists, eg bromocriptine, apomorphine
- MAOI antidepressants, eg phenelzine
- nitrates, eg glyceryl trinitrate
Since amiloride can raise the level of potassium in the blood it should not be used in combination with other potassium-sparing diuretics, eg spironolactone, eplerenone, triamterene, or with potassium supplements, as this can cause the level of potssium in the blood to rise too high. The following medicines can also raise the level of potassium in the blood and if you take any of these with amiloride the level of potassium in your blood should be regularly monitored:
- ACE inhibitors, eg captopril
- angiotensin-II receptor antagonists, eg losartan
- non-steroidal anti-inflammatory drugs (NSAIDs) such as indometacin
- potassium-containing salt substitutes, eg Lo-salt
- potassium salts, eg potassium citrate for cystitis
This medicine may reduce the ability of the body to remove the medicine lithium, which can cause the level of lithium in the blood to rise too high. If you are taking lithium your lithium level should be checked after you start and stop treatment with this medicine, as well as after any dose changes. Your lithium dose may need adjusting.
The following medicines may reduce the diuretic and blood pressure lowering effect of this medicine:
- corticosteroids, such as dexamethasone or prednisolone
- oestrogens, such as those in the contraceptive pill
- regular use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, diclofenac or indomethacin (occasional painkilling doses are unlikely to have a significant effect).
Other medicines containing the same active ingredient