[Optimal dose of acetaminophen in children]

Acetaminophen is an antipyretic and analgesic drug frequently prescribed in children. Unlike aspirin, the recommended doses for acetaminophen are different in France (20-30 mg/kg/24 h) and in the USA (65 mg/kg/24 h). The authors reviewed literature data, looking for the scientific basis of these recommendations in children. The antipyretic effect of a 7-20 mg/kg single oral dose was demonstrated versus placebo. A dose-effect relationship was established: 20 mg/kg as a single oral dose was more effective than 10 mg/kg while 5 mg/kg had little antipyretic effect. More than 10 mg/kg were required to keep on average the temperature 1.5 degrees C below the starting point for 6 hours. There was no significant difference regarding the antipyretic effects of a single 10-15 mg/kg dose using suppositories or oral suspension, although there was a greater consistency of response with the oral suspension. There was no significant difference concerning the antipyretic effect between a 10-15 mg/kg acetaminophen oral dose and the same dose of aspirin. The analgesic effect of a single 10-15 mg/kg oral dose was also demonstrated versus placebo in children. Plasma concentrations between 4 and 18 mg/l seem appropriate to obtain an antipyretic effect. Half-life is 1-3.5 h. Based on these data different dose regimens including an initial loading dose have been proposed. The simplest one is as follows: 25 mg/kg loading dose and 12.5 mg/kg every 6 h as maintenance dose.