[The antipyretic effects of aminopyrine and sodium acetylsalicylate on endotoxin-induced fever in rabbits (author's transl)].

The antipyretic effects of aminopyrine and sodium acetylsalicylate on endotoxin-induced fever in rabbits were studied relative to the route and dose of administration. Intravenous administration of aminopyrine produced a marked antipyretic effect, intracisternal administration produced a lesser effect and i.v. was the effective route. Similar results were obtained in the nonfebrile rabbits. On the contrary, the intracisternal administration of sodium acetylsalicylate reduced the body temperature to the same degree both in febrile and nonfebrile rabbits, but sodium acetylsalicylate given i.v. to nonfebrile rabbits did not reduce the body temperature. 4-aminoantipyrine and N-acetyl-4-aminoantipyrine, the major metabolites of aminopyrine had a lesser effect in the febrile rabbits. Antipyretic effects of sodium salicylate, the metabolite of sodium acetylsalicylate were similar to the effects of sodium acetylsalicylate. These data suggest that the antipyretic effects of aminopyrine may not be involved in the CNS, while the antipyretic effects of salicylate may be due to a direct action on the CNS.