Emetics

EMETICS (emetica, s. vomitiva) are used in medicine to induce vomiting with the aim of as quickly and completely as possible remove from the stomach through the esophagus and oral cavity the contents of the stomach. Mechanical methods that cause vomiting are also classified as R. s., such as irritation of the root of the tongue or the posterior wall of the pharynx, irritation of the stomach with warm water or warm milk if the stomach is strongly filled, or rather overfilled, with these liquids; irritation of the stomach with a warm solution of salt or soapy water. The mechanism of emetic action in these cases is explained by the excitation of the peripheral nerve endings of the glossopharyngeus nerve, and in the stomach—of the vagus nerve, along with irritation of the muscles of the stomach walls, and consequently the reflex excitation of the vomiting center. Also by local excitation of the sensory endings of the vagus nerve in the stomach, vomiting can be caused by medicinal substances themselves, for example ipecacuanha and the emetine obtained from it, senega root, soap bark, tartar emetic, copper sulfate and zinc sulfate, and alum. Since with stronger irritants than the substances just mentioned, vomiting still often does not occur, it can be assumed that the above-mentioned medicinal emetic substances act due to their specific properties of irritating the sensory endings of the vagus nerve; in such a case, one can speak of the selective action of these substances, whereby they already cause emetic action in relatively small doses. The possibility of obtaining emetic action from small doses of R. s. has great practical significance, because large doses of the above-mentioned medicinal R. s. cause a series of severe side effects of local and general action, despite the fact that with the vomited masses from the stomach, most of the medicinal R. substances are removed. Among medicinal substances, arsenic, administered in large toxic doses; lobelia in large doses; digitalis in high and long-used doses; pilocarpine and many others very often cause vomiting, however considered as a side effect, not characteristic of the main direct effect on which one counts in therapeutic use. Therefore, arsenic, lobelia, digitalis, pilocarpine and many other medicinal substances are not classified as therapeutic R. s., although sometimes vomiting from these preparations may prove to be a very useful protective reaction of the body against the poisonous effect of the administered medicinal substance. Among R. s., apomorphine holds a special place in terms of mechanism of action; it acts directly on the vomiting center, exciting it. Therefore, for faster and more energetic action, hydrochloride of apomorphine in solution is injected under the skin, and not taken internally, whereas medicinal substances that cause vomiting reflexively from the gastric mucosa are given per os, and not under the skin. For internal use, R. s. are prescribed in solutions, in the form of infusions, in mixtures and powders. R. s. are indicated: 1) for the rapid removal of poisonous substances or indigestible food from the stomach; 2) for the removal of large masses of sputum from the lungs threatening suffocation, as observed in children and the elderly; 3) for the detachment and removal of inflammatory (diphtheritic) membranes from the fauces and the upper part of the respiratory tract by the particularly energetic expiratory movements during vomiting; 4) for the removal of foreign bodies that have entered the respiratory tract, with threatening suffocation and in the absence of surgical help; 5) to eliminate or reduce edema of the glottis; 6) to enhance the secretion of sputum and facilitate expectoration, for which some of the medicinal emetics are used—ipecacuanha, senega, antimony preparations—as having the property, after remaining in the body for a relatively long time, to increase the secretory activity of the bronchial mucosa. R. s. are contraindicated: 1) in pregnancy, hernia and significant curvature of the spine; 2) in aneurysm, arteriosclerosis, diseases of the heart, tendency to cerebral congestion, with high blood pressure and venous stasis; 3) in severe general weakness; 4) with significant lesions of the stomach or esophagus by ulcer, cancer and especially by burn from sulfuric acid or from other caustic substances—acids or alkalis; 5) in inflammations of those organs on which the diaphragm or abdominal muscles press during vomiting (peritoneum, stomach, intestines, liver and kidneys); 6) in the unexcitability of the vomiting center. In most cases, when it is necessary to remove the contents of the stomach, the best method is repeated washing of the stomach using a gastric tube, thanks to which it has become possible to significantly reduce the number of cases of using R. s.