A p-aminophenol derivative with analgesic and antipyretic activities.
Although the exact mechanism through which acetaminophen exerts its effects has yet to be fully determined, acetaminophen may inhibit the nitric oxide (NO) pathway mediated by a variety of neurotransmitter receptors including N-methyl-D-aspartate (NMDA) and substance P, resulting in elevation of the pain threshold.
The antipyretic activity may result from inhibition of prostaglandin synthesis and release in the central nervous system (CNS) and prostaglandin-mediated effects on the heat-regulating center in the anterior hypothalamus.
PO: 0.5-1 g 4-6 hrly. Max: 4 g/day.
PR supp: 0.5-1 g 4-6 hrly. Max: 4 g/day.
IV: 33-50 kg: 15 mg/kg as a single dose, at least 4 hrly. Max: 60 mg/kg/day up to 3 g/day; >50 kg: 1 g as a single dose, at least 4 hrly. Max: 4 g/day. Admin by infusion over 15 min.
Adverse drug reactions: thrombocytopenia, leucopenia, pancytopenia, neutropenia, agranulocytosis, pain and burning sensation at inj site, acute renal tubular necrosis and hepatotoxicity. See reference for details.