Biogesic Overdosage

Paracetamol in massive overdosage may cause hepatic toxicity in some patients. In adults and children >12 years, hepatic toxicity may occur following ingestion of >7.5-10 g over a period of ≤8 hrs. Fatalities are infrequent (<3-4% of untreated cases) and have rarely been reported with overdoses of <15 g. In children <12 years old, acute overdosage with paracetamol <150 mg/kg body weight have not been associated with hepatic toxicity. Early symptoms following a potentially hepatotoxic overdose may include: Nausea, vomiting, diaphoresis and general malaise. Clinical and laboratory evidence of hepatic toxicity may not be apparent until 48-72 hrs after ingestion. In adults and children >12 years, any individual presenting with an unknown amount of paracetamol ingested or with a questionable or unreliable history about the time of ingestion should have a plasma paracetamol level drawn and be treated with N-acetylcysteine. Results of assays for plasma paracetamol levels should not be awaited before initiating treatment with N-acetylcysteine. The following additional procedures are recommended: Promptly initiate gastric decontamination of the stomach. A plasma paracetamol assay should be obtained as early as possible, but no sooner than 4 hrs following ingestion. Liver function studies should be obtained initially and repeated at 24-hr intervals.
Serious toxicity or fatalities have been extremely infrequent following acute paracetamol overdose in young children, possibly because of differences in the way children metabolize paracetamol. In children, the maximum potential amount ingested can be more easily estimated. If >150 mg/kg or if an unknown amount of paracetamol was ingested, obtain a plasma paracetamol level as soon as possible, but no sooner than 4 hrs following ingestion. If an assay cannot be obtained and the estimated paracetamol ingestion exceeds 150 mg/kg, dosing with N-acetylcysteine should be initiated and continued for a full course of therapy.