Recent developments in the management of paracetamol (acetaminophen) poisoning

Abstract

Paracetamol (acetaminophen) poisoning accounts for almost a third of admissions to our district poisons unit, and is the commonest cause of death in such patients. Antidotal treatment may be effective up to 10h after overdose with oral methionine or up to 24h with acetylcysteine (not 15h as previously suggested for the latter). Patients taking paracetamol overdose while also receiving drugs which induce hepatic enzymes are more susceptible to liver damage, and antidotal treatment may be necessary at lower plasma paracetamol concentrations (50% of the normal treatment line). As survival following liver transplantation is now increasing, it is important to identify early prognostic indicators in fulminant hepatic failure, so that those patients with a high chance of fatal outcome can be considered for transplantation. Useful indicators are the presence of acidosis, marked prolongation of prothrombin time or a continued rise in prothrombin time on day 4 after the overdose. There is no evidence that paracetamol or acetylcysteine are teratogenic in pregnancy. Delays in administering acetylcysteine after paracetamol poisoning in pregnancy have been shown to increase the risk of spontaneous abortion and fetal death. Thus, acetylcysteine should be started as early as possible where treatment is indicated.