Phenytoin toxicity and hepatic encephalopathy: simulation or stimulation?
Two cases of phenytoin toxicity in patients with chronic liver disease who were taking 300 mg phenytoin daily are described. Each patient developed encephalopathy, characterized by confusion, disturbed conscious state, asterixis, and nystagmus, which was resistant to treatment with protein restriction, lactulose, and neomycin, but responsive to withdrawal of phenytoin. We suggest that the phenytoin did not precipitate hepatic encephalopathy, but caused an encephalopathy that mimicked it. We recommend that phenytoin be used cautiously in patients with liver disease, and that the drug's unbound serum level be measured if encephalopathy occurs.
D003951:Diagnostic Errors; D005260:Female; D006501:Hepatic Encephalopathy / Q000139:chemically induced* / Q000175:diagnosis; D006801:Humans; D008108:Liver Diseases, Alcoholic / Q000150:complications; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000009:adverse effects* / Q000627:therapeutic use; D012640:Seizures / Q000188:drug therapy / Q000209:etiology
D010672:Phenytoin