PMC9107358_01
Acetaminophen concentrations, ALT, and AST vs. time post-ingestion. Note: 16 h acetaminophen concentration was measured retrospectively after the patient developed hepatotoxicity.
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The acetaminophen level was well below the treatment nomogram line, timed from the earliest possible time of ingestion of 4.5 h (Figure 1). This remained well below the nomogram line at 8.5 h (presumed earliest possible time of ingestion) (Figure 1). Repeated pathology at 38 hours post-ingestion revealed an acute liver injury (ALI) with an ALT of 489 U/L, INR of 1.5, and acetaminophen level of 85 mg/L (560 mumol/L) (Figure 1).
Acetaminophen and metabolite concentrations vs. time post-ingestion.
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fig2
These included nontoxic glucuronide (APAP-Glu) and sulfate (APAP-Sul) conjugates and adducts of the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), including acetaminophen-cysteine (APAP-Cys) and acetaminophen-mercapturate (APAP-Mer) (Figure 2). AUC for each metabolite was compared to the sum of AUC of all metabolites. APAP-Glu and APAP-Sul accounted for 68% (AUC 8663 (mumol/L)*hr) and 22% (AUC 2733 (mumol/L)*hr) of the total metabolites, respectively, while the metabolites APAP-Cys and APAP-Mer reflect the metabolism of acetaminophen by the cytochrome P450 (CYP) enzyme system, combined accounted for 10% (AUC 1254 (mumol/L)*hr) of the total metabolites (Figure 2).