Simulated acetaminophen overdose: pharmacokinetics and effectiveness of activated charcoal.

Study Objective: To determine the absorption rate of a supratherapeutic dose of acetaminophen elixir and compare the effect of activated charcoal (AC) given at different time intervals on preventing acetaminophen absorption.

Design: Randomized, nonblinded, crossover controlled study.

Setting: A certified regional poison control center.

Participants: Ten healthy, adult male volunteers from 21 to 39 years old.

Interventions: Each subject received 5 g acetaminophen (elixir) on four occasions: a control phase plus 30 g of AC administered 15, 30, or 120 minutes after acetaminophen. Serum acetaminophen levels were obtained during the control phase only, and 24-hour urine collections were obtained during all four phases.

Measurements And Main Results: The highest serum acetaminophen levels were measured 1.4 +/- 0.52 hours after ingestion, and absorption was 97% complete by a mean of 2.05 hours. The administration of AC at 15, 30, and 120 minutes after acetaminophen reduced urinary recovery of acetaminophen and metabolites by 48%, 44%, and 33%, respectively.

Conclusion: AC significantly reduces urinary recovery but not absorption of acetaminophen when administered two hours after acetaminophen elixir.