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.
Subsulphate of Mercury.
Water (lukewarm and in copious draughts).
Strong infusions of vegetable bitters, as camomile, quassia, etc.
Ipecacuanha and Emetine.
Muscarine, Urechitine, Digitalis and its congeners, not used medicinally as emetics.
The action of local emetics is confined to that of producing vomiting, which is generally not long continued, ceasing after the emetic has been evacuated, and is not accompanied by much general depression.
The vomiting occasioned by general emetics, on the other hand, is much longer continued, and is accompanied by great general depression, nausea, languor, muscular weakness, en-feeblement of the circulation, and increase of the secretions, especially those of saliva, sweat, and mucus in the oesophagus, stomach, and bronchial tubes.
Uses. - Emetics may be used for the purpose of simply emptying the stomach, or the violent expulsive efforts which they occasion may be utilised in order to remove foreign bodies or secretions from the oesophagus or from the biliary or respiratory passages.
1. Emetics may be used to cause the expulsion of foreign bodies, such as pieces of gristle or meat which have become impacted in the upper part of the oesophagus, and, by pressing on the larynx, are giving rise to suffocation. In such cases apomorphine given subcutaneously, or injected into a vein in the dose of 1/12 th or 1/10 th of a grain, will be found of service.
2. They may be used to remove the contents of the stomach when these, instead of undergoing digestion and absorption in the normal manner, have undergone fermentative changes and become acid, acrid, and irritating, giving rise to pain, either in the stomach itself, or in some other organ, as in the head. In gastralgia, or in headache either depending upon indigestion, or associated, like sick-headache, with a tendency to vomiting, large draughts of warm water often give relief. Their emetic action may be aided if necessary by tickling the fauces with the finger, or by using strong camomile tea, or mustard and water in place of water alone. Simple draughts of warm water, however, may relieve the gastralgia or headache without causing vomiting. They appear to do so by simply diluting the acrid contents of the stomach so much that they no longer irritate the mucous membrane.
3. Emetics remove the poison from the stomach in cases where it has been swallowed. Here mustard and water is very useful, as it is the emetic which is most likely to be at hand; but sulphate of copper and sulphate of zinc if readily procured are to be preferred, as they empty the stomach most quickly and effectually. In cases of poisoning by laudanum, the nerve-centres are so much deadened by the narcotic that they may not respond to the stimulus even of large doses of these emetics, and then it may be necessary to employ the stomach-pump or gastric syphon.
4. To expel bile from the gall-bladder, to drive small gallstones through the gall-duct. The bile is secreted under a very low pressure, and a very slight obstruction in front may prevent its flow through the gall-duct and occasion its accumulation in the gall-bladder and biliary capillaries. The compression of the liver between the diaphragm and abdomen muscles, even in ordinary respiration, tends greatly to dispel the bile from the liver, and this expulsive action is of course greatly increased during the violent efforts of vomiting. During these efforts the bile may be forced through the gall-duct, driving before it the obstruction which has been occasioned by the accumulation of mucus within it due to catarrh, or by the impaction of a small biliary calculus. In this manner emetics may remove jaundice due to obstruction.
5. To remove bile from the body in cases of biliousness, fevers, and ague. In biliousness the emetics have got the double action of expelling the bile from the liver in the way just mentioned, and of removing it from the body through the stomach. When bile passes along the intestines, not only is it re-absorbed, but poisonous matters from the intestine are absorbed with it. When it is ejected from the stomach by the efforts of vomiting, no time is allowed for its re-absorption, and so both the bile itself, and any poisonous matter which it contains, are more rapidly and certainly removed from the body. It is probable that the malarious poison circulates in the bile, and possibly also other poisons which give rise to fevers. There can be no doubt of the advantages to be derived from the use of emetics in ague before the administration of quinine; and indeed cases of ague may be sometimes cured by the use of emetics alone without quinine, while quinine without emetics is not unfrequently of very little use in bad cases. Emetics have also been recommended in the early stages of continued fevers, in order to remove the poison on which they are supposed to depend. For such purposes ipecacuanha or tartar emetic is best.
6. To remove obstructions from the air-passages, such as false membranes from the trachea and bronchia in croup or diphtheria, or the over-abundant secretion which is clogging the bronchi and interfering with respiration in bronchitis, and more rarely in phthisis. Ipecacuanha is the emetic most readily chosen in such cases, as it tends to increase the secretion from the air-passages, as well as to produce vomiting. When it does not act rapidly, sulphate of zinc or sulphate of copper may be used, and a teaspoonful of alum is a very efficient remedy in croup. When there is much depression of the circulation, carbonate of ammonium is to be preferred as an emetic, inasmuch as it stimulates the circulation, as well as causes vomiting.
Contra-indications. - Emetics must be avoided in persons suffering from aneurism, and used with care in persons suffering from atheroma or a tendency to haemorrhage from the lungs or uterus, lest the high blood-pressure which occurs during the efforts of vomiting should lead to the rupture of a blood-vessel. They should be used with caution also in persons suffering from hernia, or who have a tendency to it, or from prolapsus of the uterus. In pregnancy we often find obstinate vomiting lasting for a length of time, and yet producing no abortion; but where a tendency to abortion exists, emetics should be avoided if possible.