McNeil Consumer Available as 160 mg of acetaminophen. McNeil Consumer Available as 160 mg of acetaminophen per 5 ml. McNeil Consumer Available as 80 mg of acetaminophen in a chewable formulation. Acetaminophen's exact mechanism of action is unknown. The antipyretic activity is exerted by blocking the effects of endogenous pyrogen on the hypothalamic heat-regulating center, possibly by inhibiting PG synthesis.
Heat is dissipated by vasodilation, increased peripheral blood flow, and sweating.
An analgesic effect may be produced by a direct action on the pain threshold. This effect is believed to be due to inhibition of PG synthesis or inhibition of the synthesis or actions of chemical mediators or other substances that sensitize the pain receptors to mechanical or chemical stimulation. Acetaminophen does not possess peripheral antiinflammatory activity. Chronic ingestion of acetaminophen may lead to hepatotoxicity or nephrotoxicity. The mechanism of either toxicity may be similar.