Hyperpyrexia and antipyresis owing to sodium acetylsalicylate in intact and decapitate cats.

Sodium acetylsalicylate (100 mg/kg) intravenously injected into anaesthetized intact or decapitate cats caused an increase in body temperature. At a dosage of 30 mg per kilogram it caused a lowering of body temperature in the intact preparations, but again an increase in decapitate preparations. At a dosage of 10 mg per kilogram, no significant temperature change occurred in either type of preparation. Aspirin (in the form of sodium acetylsalicylate) is a systemic pyrogen and a centrally acting antipyretic. When it occurs, aspirin antipyresis must take place in the face of systemic pyrogenesis. Notable is the fact that aspirin (30 mg/kg) in the intact preparation lowers body temperature not only from fever levels, but also from normal and subnormal levels.