ANTIPYRIN, the trade name of an arti ficial alkaloidal substance known to the chemist as oxydimethyl-quinizin, or, more accurately, as oxy-phenyl-di-methyl-pyrazole. It is a crystal line substance melting at 235° F. and soluble in water, alcohol, ether, and chloroform. An tipyrin is a derivative of coal-tar, an or ganic nitrogenous basic compound with the composition C1 1122N,O. It forms colorless scaly crystals devoid of odor and with a slightly bitter taste. It is soluble in water, alcohol and chloroform. It is one of the first of the modern army of synthetic drugs, and is still one of the most valuable, though not so extensively lauded as formerly, the patent on its exclusive production by one manufacturer having expired in 1899. Its action locally is somewhat antisep tic, and solutions applied to mucous membranes render them slightly anmsthetic and contract the blood vessels. It therefore makes a good local application to catarrhal membranes. Taken internally it is readily absorbed, reduces the force and frequency of the heart action, causes a dilatation of the blood-vessels of the periph ery of the body, thus bringing about sweating and increased heat elimination (see ANIMAL HEAT). Its chief antipyretic action is due to the co-ordinating mechanism which lowers the heat at the point where the temperature is main tamed and accumulated (the slcin); the dilata tion of the capillaries brings about the dissipa tion of this accumulation, which vascular dilata tion is caused by the action of the heat-regulat ing mechanism possibly situated at the base of the cerebrum. Antipyrin is also an efficient and
valuable analgesic, particularly serviceable in headache, neuralgias, in dysmenorrhoea, in rheu matism and in affections of the peripheral nerves and joints generally. By its pain-reliev ing qualities it makes a valuable adjunct in hypnotic mixtures. It is also a good antispas modic.
Antipyrin is mainly eliminated by the kid neys. It may cause symptoms of poisoning. These are collapse, cold extremities and some degree of cyanosis and heart weakness. It is not one of the aniline (q.v.), analgesic antipyret ics and hence has not the characteristic blood poisoning properties of the anilines (acetanilide exalgen, mathacetin and similar bodies). It may produce a number of untoward symptoms, not ably skin eruptions, cramps of the intestine and of the bladder. It also may cause disturbances of sensation in the extremities. Doses of from 10 to 15 grains have caused serious symptoms of poisoning, particularly in children. See ANAL