Inadequacy of reported intake in assessing the potential hepatotoxicity of acetaminophen overdose

No evidence of liver damage was found in a series of 22 patients with acute acetaminophen overdose, 13 of whom reported ingesting doses of 10 to 25 g, which is within the accepted hepatotoxic range. Serum acetaminophen concentrations did not exceed 160 micrograms/ml, an amount well below the minimal hepatotoxic level. Moreover, mean serum concentrations of acetaminophen in patients reporting the ingestion of less than 10 g [74 +/- 48 (SD) micrograms/ml) were similar. Throughout the study, no correlation was found between serum concentrations and the reported dose ingested. Poor bioavailability of local acetaminophen formulations was ruled out as a factor in the dose-concentration discrepancy by comparison with a British formulation ingested by four volunteers. We conclude that information regarding dose ingestion given by patients admitted to hospital for self-poisoning is inaccurate and often exaggerated. Management of acute acetaminophen overdose must be based on serum concentrations of acetaminophen and not on the reported dose.