[Study of the serum concentrations of acetaminophen overdose]

Acetaminophen (APAP) is a commonly used nonsteroidal analgesic because it is considered safe. However, APAP is a major cause of acute poisoning because of its easy availability. APAP overdose causes hepatic failure. A previous study reported a case of death occurring 3-4 days after APAP overdose. Serum APAP level is an index for administration of N-acetyl-L-cysteine (NAC). We investigated cases of APAP overdose to determine the correlation between serum APAP level and estimated APAP dosage, NAC medication, hepatic failure, etc. In one case, we found that the use of estimated APAP dosage alone led to inappropriate NAC medication. Moreover, there were cases in which serum APAP level increased 4 hr after APAP overdose. Repeated cases of APAP overdose suggested that the presence of NAC medication caused a difference in liver function test values.