[Antipyretic activity of 3-amino-4-mercapto-6-methylpyridazine and some standard pharmaca]

The induction of fever in the rat by means of yeast homogenates was used to evaluate the antipyretic activity of several pharmaca. Apart from 3-amino-4-mercapto-6-methylpyridazine (1; pyridazine S1), the author tested acetylsalicylic acid, phenacetin, aminophenazone, phenylbutazone and indometacin. The antipyretic activity of 1 was almost equal to that of aminophenazone. Dose-response relationships provided security for the comparison of the activities of these two pharmaca. The relatively low toxicity of 1 (nearly five times less than that of aminophenazone) was noteworthy. The antipyretic activity of 1 was not inhibited by atropine. The possible central attack mechanisms of pyridazine (which produce a decline of fever) are discussed in connexion with data from the literature.