Test Background Paracetamol (acetominophen) is an analgesic, antipyretic drug lacking significant anti-inflammatory activity. It is metabolised by the liver with a normal elimination half-life of <4 hours. In normal therapeutic doses, a minor metabolite readily reacts with glutathione in the liver to yield a detoxified product. In overdose situations, liver glutathione is consumed and the toxic metabolite (postulated metabolite: benzoquinone) reacts with cellular proteins resulting in hepatotoxicity and possible death if untreated. N-acetylcysteine can substitute for glutathione and serves as an antidote.
Clinical Indications Suspected overdose: symptoms include nausea and vomiting, right subcostal pain and tenderness (hepatic necrosis).
Reference Range See British National Formulary for overdose guidelines