Many of the synthetical coal-tar products now so largely employed as analgesics are powerful toxic agents.
Phenazone, Antipyrine, or Analgesin, is a complex benzene derivative prepared from aniline, aceto-acetic ether, and methyl iodide. It is in colourless, inodorous, scaly crystals, which have a bitter taste. It is soluble in its own weight of water.
Tests.—Can be extracted from an alkaline solution of chloroform. The residue left on the evaporation of chloroform should be employed for testing. If heated with strong nitric acid and allowed to cool, a purple colour is produced. Ferric chloride gives a blood-red coloration, destroyed by the addition of mineral acids.
Treatment.—Stimulants freely, inhalation of oxygen, patient to be kept in the recumbent position.
Acetanilide, Antifebrin, Phenylacetamide (a constituent of 'Daisy' or 'headache' powders), is obtained by the interaction of acetic acid and aniline. It is in colourless, inodorous, lamellar crystals, which have a slight pungent taste. It is insoluble in water.
Tests.—May be extracted from acid solutions by ether or chloroform. If heated with solution of potassium hydroxide, odour of aniline is given off; if liquid, when it is warmed with a few drops of chloroform, a penetrating and unpleasant odour of isocyanide.
Treatment.—Emetics, stimulants, inhalation of ether, recumbent position.
Phenacetin, Phenacetinum, is produced by the interaction of glacial acetic acid and para-phenetidin. It is in white, tasteless, inodorous, glistening, scaly crystals, insoluble in water. Of all the members of the group, it most rarely produces toxic symptoms.
Treatment.—As for the other members of this group.
Exalgin, Aspirin, etc., as well as the above, may all act as poisons to certain persons, and even small medicinal doses may cause serious and even fatal consequences.