STRYCHNINE, an alkaloid discovered in 1818 in St. Ignatius's beans (Strychnos Ignatii) ; it also occurs in other species of Strychnos, e.g., S. Nux vomica, S. colubrina, S. Tieute, and is generally accompanied by brucine, Strychnine crystallizes from alcohol in colourless prisms, prac tically insoluble in water, and with difficulty soluble in the com mon organic solvents. Its taste is exceptionally bitter. It has an alkaline reaction, and is a tertiary monacid base.
As regards its physiological action, strychnine enters the blood as such, being freely absorbed from mucous surfaces or when given hypodermically. Internally it acts as a bitter, increasing the secretion of gastric juice and intestinal peristalsis. The spe cific effects of the drug, however, are upon the central nervous system. It excites the motor areas of the spinal cord and increases their reflex irritability. Small doses increase the sensibility of touch, sight and hearing ; large doses cause twitching of the muscles and difficulty in swallowing; while in overdoses violent convulsions are produced. The cerebral convolutions remain unaffected, but the important centres of the medulla oblongata are stimulated. Not only is the respiratory centre stimulated but
the cardiac centre is acted upon both directly by the drug and indirectly for a time by the enormous rise in blood pressure due to the contraction of the arterioles all over the body. Ordinary doses have no effect upon the temperature but in overdose the temperature rises during a convulsion. Strychnine is eliminated by the kidneys as strychnine and strychnic acid. It is excreted very slowly and therefore accumulates in the system.
In collapse following severe haemorrhage and arrest of the heart or respiration during chloroform narcosis an intramuscular injection of gr. of the hydrochloride may stimulate the cardiac action. In acute opium poisoning strychnine is very valuable. It is a physiological antagonist of chloral hydrate, morphine and physostigmine, and may be given in poisoning by these drugs. symptoms of strychnine poisoning usually appear within twenty minutes of the ingestion of a poisonous dose, starting with stiffness at the back of the neck, twitching of the muscles and a feeling of impending suffocation. The patient is then seized with violent tetanic convulsions. After a minute the muscles relax, and the patient sinks back exhausted, conscious ness being preserved throughout. Tetanus (q.v.) resembles strych nine poisoning, but the development of the symptoms in tetanus is usually much slower, death rarely occurring within 24 hours. The treatment of strychnine poisoning is immediate evacuation of the stomach by stomach-pump or emetic, chloroform being administered to allay the spasms. Chloral and potassium bromide may be given as physiological antidotes.