Lack of effect of multiple doses of cimetidine on estimated hepatic blood flow.

Conflicting data exists regarding the effect of the H2-receptor blocking agent cimetidine on hepatic blood flow (HBF). The variance in the results of these studies may be due in part to differences in the duration of cimetidine administration, the posture of the volunteers during their course of study, and the method used to estimate HBF. To assess the effects of chronic cimetidine (300 mg q.i.d. X 4 days) on estimated HBF while controlling posture (supine and standing), a double-blind, placebo-controlled, repeated measures study was performed in 9 healthy males. Indocyanine green (ICG) plasma clearance after an i.v. dose of 0.5 mg kg-1 was used to calculate HBF. ICG plasma concentrations were measured by HPLC. Compared to placebo treatment, cimetidine had no effect on mean (SD) estimated HBF (ml min-1 m-2) in either the supine (497 (64) vs 494 (80] or the standing (443 (117) vs 404 (89] posture. These data had a power greater than 0.8 to detect a treatment effect of 20 per cent. Standing produced a significant decrease in estimated HBF (496 (70) vs 424 (102); p less than 0.01). In contrast to previous reports, chronic cimetidine treatment had no apparent effect on hepatic blood flow.

RCT Entities:   Population Interventions Outcomes