Abnormal drug metabolism after barbiturate and paracetamol overdose.

Drug-metabolizing capacity has been assessed by serial measurements of the plasma antipyrine half life in 11 patients with severe barbiturate intoxication and in 17 patients with acute hepatic necrosis due to paracetamol overdosage. Drug metabolism was strikingly enhanced after barbiturate over-dosage, and this effect was still present six weeks later. In contrast the antipyrine half life was greatly prolonged in patients with paracetamol-induced acute hepatic necrosis but returned to normal or near-normal values within seven to 21 days.