Hepatic encephalopathy and altered cimetidine kinetics.
Cimetidine kinetics were followed in 16 cirrhotic patients after a single IV 300-mg dose. The patients were grouped according to a history of portal systemic encephalopathy (PSE). There were no differences among the groups in volume of distribution, biologic t 1/2, or distributional clearance. In cirrhotic patients with no history of PSE, cimetidine kinetics and metabolism were the same as in healthy subjects. Patients with a history of PSE (n = 8) had lower cimetidine total body clearance than cirrhotic patients without a history of PSE and healthy subjects. Cirrhotic patients with a history of PSE also had decreased formation of cimetidine sulfoxide (as judged by differences in the sulfoxide serum concentration-time AUC). Because of the 40% decrease in total clearance, dosage in cirrhotic patients with a history of PSE should be reduced to minimize the risk of CNS side effects associated with cimetidine.
D000328:Adult; D002927:Cimetidine / Q000009:adverse effects / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism*; D005260:Female; D006146:Guanidines / Q000378:metabolism*; D006501:Hepatic Encephalopathy / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008103:Liver Cirrhosis / Q000188:drug therapy / Q000378:metabolism; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged
D006146:Guanidines; D002927:Cimetidine; C034042:cimetidine sulfoxide