This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
When applied directly to the heart of a frog, it first increases, then slows, and finally arrests its pulsations in diastole. This action appears to be chiefly due to paralysis of the cardiac muscle itself, and possibly also to the effect upon motor ganglia.
The effect of antimony upon the circulation appears to depend partly upon the direct action of the drug upon the heart and vessels, and partly on its reflex action upon them through the nerves of the stomach. In warm-blooded animals the pulse becomes quicker as the feeling of nausea increases, and, after the vomiting, again falls nearly to the normal. Its volume is at the same time diminished. After the nausea has ceased, the pulse again becomes quicker, and after this secondary acceleration has reached a greater or less height, according to the dose, it again sinks to the normal.
As the primary acceleration during the stage of nausea ceases with vomiting, it is probably to be attributed to reflex irritation of the accelerating centres, or reflex depression of the vagus through the gastric nerves, whereas the cause of the secondary acceleration is more probably to be sought in diminished power of the vagus nerve itself. The blood-pressure sinks constantly from the very beginning, and this sinking is probably due to diminished power of the cardiac pulsations. The temperature in the extremities appears to be diminished during the stage of nausea, owing to the smaller amount of blood going to them. As less blood reaches the surface in this condition, there is less opportunity afforded for its being cooled by contact with the atmosphere, and the temperature in the body gradually rises, even above the normal. When the spasm of the vessels in the extremities relaxes, they also become warmer than normal. As the effects pass off, the temperature sinks to the normal or below it.
The respiration is first increased, and then diminished.
Large doses of antimony affect the spinal cord both in cold-and warm-blooded animals. It appears to paralyse, after, perhaps, slightly exciting, both the sensory and motor tracts of the spinal cord, and as this paralysis appears in frogs while the heart still continues to beat, it must be due to the direct action of the drug upon the nervous system itself, and not to its indirect action through the circulation. The motor and sensory nerves appear also to be paralysed. The muscles are weakened (p. 127).
When given for a length of time, antimony seems to produce fatty degeneration of various organs.
The action of antimony upon the skin in frogs is even more rapid than that of arsenic (p. 716), and differs from it in this respect, that the softening does not affect the cells of the columnar layer only, but extends to those of the intermediate layer (Fig. 172). In consequence of this, the cuticle does not merely become detached from the dermis and peel off in strips as in poisoning by arsenic, but the cells of the epidermis becoming detached from each other, the cuticle becomes converted into a soft jellylike mass which can be scraped or brushed off.
Fig. 172. - Vertical section of epidermis from a frog poisoned by antimony, a, Columnar layer in which large cavities are formed, b, Columnar cells in which the reduced protoplasm is drawn into processes, c, Spaces in the intermediate layer, d, Light lines between cells indicating a softening and separation of cells. (After Nunii.)
Tartar emetic appears to be eliminated by the mucus of the stomach and alimentary canal, by the bile, and by the kidneys. Its action upon the renal secretion is somewhat uncertain. It appears to increase urea, uric acid, and pigment, and to diminish the water and the chloride of sodium, probably by increasing the perspiration.
Uses. - The local uses of antimony will be considered under the special preparations.
When antimony is given internally for its action on the system generally, tartar emetic is the preparation usually employed, but the other preparations of antimony have a similar action when given in appropriate doses. It can be used for its emetic action, nauseant and depressant action, or diaphoretic action. As an emetic it has been employed in cases of croup, in order to cause expulsion of the false membrane; but for this purpose other emetics, such as ipecacuanha, alum, or sulphate of zinc, are now more generally employed, as they do not cause so much depression. It has also been used with considerable success to cut short an attack of intermittent fever, either alone or combined with a purgative. Indeed, in cases where malarial poisoning has been intense, quinine sometimes proves ineffectual unless preceded by the administration of an emetic and purgative. It has sometimes been injected into the veins to produce vomiting, in cases of obstruction of the oesophagus, as, for example, by a piece of meat firmly lodged in it, and to cause expulsion of a biliary calculus lodged in the gall-duct, by the pressure from behind which the movements of vomiting produce, along with the relaxation of the muscular fibres of the gall-duct itself.
When large doses are administered several times, what is termed tolerance of the drug sets in, and it no longer produces vomiting. It has been used in this way in pneumonia, but the plan is now rarely followed. How this tolerance is produced is not at present understood. It is not improbable that it may be caused by the irritant action of the first few doses upon the stomach arresting the secretion of the acid juice, and producing a condition similar to that which occurs in fever. In this condition subsequent doses of the tartar emetic, meeting with no acid, will have but a feeble action upon the stomach.
In cases of obstinate constipation it has been used along with sulphate of magnesium. As a nauseant it has been given to relax the cervix uteri in labour; in acute inflammations, e.g. in acute orchitis, where the emetic is first given, and nausea is kept up by a continued administration of smaller doses; and also in pericarditis, pneumonia, pleurisy, peritonitis, meningitis, bronchitis, and hepatitis, as well as in acute rheumatism. As an expectorant it is used in bronchitis. The cases in which it is especially serviceable are those in which there is great congestion and much dyspnoea, with little or no secretion, as shown by loud, sibilant rales over the chest, the pulse being full, and the face flushed, with a tendency to lividity. It has also been given to check haemoptysis when there is much excitement of the circulation. As a sedative it is of use in nervous diseases, attended with much excitement, such as certain cases of insanity, delirium tremens, and puerperal convulsions. In the delirium of fever, it has been highly recommended by Dr. Graves, in combination with opium, as a means of producing sleep. Where the delirium is furious the tartar emetic must be given in full, and the opium in small doses; while if the delirium is milder and the sleeplessness great, the opium dose must be increased and that of the tartar emetic diminished. The same treatment may be adopted in the delirium and sleeplessness of delirium tremens.
For its diaphoretic action, antimony has been used to arrest commencing inflammations, such as catarrh, and to check febrile conditions. For this purpose it is not unfrequently given as tartar emetic in doses of 1/16 grain frequently repeated, or as James's powder. In acute dropsy it appears to be occasionally useful, especially as a diaphoretic, in combination with bitartrate of potassium and squills.
Preparations containing Antimony.
Antimoniura Nigrum Purificatum.
Liiquor Antimonii Chloridi. Pilula Hydrargyri Subchloridi Composita (v. p. 522). Pulvis Antimonialis. Unguentum Antimonii Tartarati. Vinum Antimoniale.
Antimonii et Potassii Tartras.
„ „ Purificatum.
Pilulae Antimonii Compositae (p. 523).
Pulvis Antimonialis. Syrupus Scillae Compositus. Vinum Antimonii.