Persistently elevated acetaminophen concentrations for two days after an initial four-hour non-toxic concentration

The decision to treat patients who overdose with n-acetylcysteine is routinely made with a single APAP concentration drawn 4 or more hours post-ingestion. However, in cases where there are co-ingestants that may delay gastric emptying, there have been recommendations for additional concentrations to determine peak APAP concentrations. This report is of a case of acetaminophen overdose involving narcotic co-ingestants with persistenty elevated acetaminophen concentrations for 2 d, suggesting delayed gastric emptying and/or bezoar formation. A second striking feature of this case was the persistently elevated acetaminophen concentrations without evidence of liver injury despite antidotal therapy not being employed.