Early prediction oftheoutcome ofaparacetamol overdose based onananalysis of163patients

Summary Clinical andbiochemical dataobtained from163 patients whohadtaken anoverdose ofparacetamol wereexamined todetermine which factors ormeasurementswereofvalue inpredicting theseverity of ensuing liver damage early after ingestion oftablets. Although theoverall severity ofhepatic necrosis was found toincrease withthedoseofparacetamol ingested, correlation wasnotsufficiently close toprovide anaccurate prognostic index inindividuals. Severe hepatic damage waslesslikely ifthepatient had vomited orhadastomach wash-out within 6hrof overdose. Theplasma concentrations ofparacetamol, measured atknowntimes after overdose, distinguished those whodeveloped hepatic dysfunction fromthose whodidnot, butthere wasapoor correlation, particularly inthefirst 6hrafter ingestion oftablets, between these values andtheseverity ofensuing liver damage. Estimates ofearly plasma paracetamol half-lives from three ormoresamples taken within 4hrofadmission showed that allpatients developing moderate orsevere liver damage hadhalf-lives greater than4hr, butthis wasalsothecaseinnearly one-third ofthose with minimal liver lesions only. Itisconcluded thatthere isnocompletely reliable early prognostic testforindividual patients with paracetamol overdose. Ifeachpatient isselected for treatment withcysteamine (mercaptamine) orother agents onthebasis ofplasma paracetamol levels, upto 30%mayreceive thisagent whoareatriskfrom trivial hepatic damage only.