['Antipyrine metabolism is a "gold standard" measure of mixed cytochrome P450 (CYP) mediated drug metabolism in humans. Cytokines (e.g., interleukin-6) and nitric oxide reduce CYP 450 activity in vitro and in vivo. Because interleukin-6 and nitric oxide production increases in children with sepsis-induced multiple organ failure, we hypothesized impaired CYP 450 mediated drug metabolism in this population.', 'Fifty-one consecutive children with sepsis and six critically ill children without sepsis were enrolled and given 18 mg/kg antipyrine per NG. Plasma antipyrine elimination rate, elimination half-life, and apparent oral clearance were measured and calculated. Plasma interleukin-6 and nitrite plus nitrate levels were measured and organs failing scored on days 1-3 of sepsis.', 'Children with sepsis had a twofold reduction in antipyrine clearance. Children with persistent failure of three or more organs had a fourfold reduction in antipyrine clearance. Antipyrine clearance was inversely correlated to circulating interleukin-6 and nitrite plus nitrate levels and to number of organ failures.'] Is cytochrome P450 mediated-drug metabolism reduced in children with sepsis-induced multiple organ failure?