Acetaminophen Acetaminophen is believed to produce its antipyretic effect through central inhibition of the cyclo-oxygenase pathway, blocking the production of prostaglandins which stimulate elevation of the hypothalamic temperature set point. The pharmacokinetics of acetaminophen have been studied in several groups of children. 1,7 Peak serum concentrations occur 30 minutes to 1 hour after ingestion of liquid dosage forms. Maximum antipyretic effect usually lags behind the time of maximum concentration, occurring in most patients at 1-1.5 hours. Acetaminophen is primarily eliminated via hepatic metabolism to water-soluble compounds which are then excreted in the urine.
Metabolic pathways differ with age.
Adverse reactions are rare following appropriate acetaminophen use. Hypersensitivity reactions, hematologic abnormalities, and impaired renal function have been reported. The most serious risk associated with acetaminophen use is hepatotoxicity associated with an overdose. For those readers interested in further information on the management of acetaminophen toxicity, Kiebler and Mowry 6 provide a more in-depth review. Accurate dosing by care providers is an area of concern.