Abstract
The inhibitory effect of famotidine, a new H2-receptor antagonist, on hepatic oxidative metabolism of cortisol in six healthy volunteers was compared with that of cimetidine by monitoring the change in urinary 6β-hydroxycortisol (6β-OHF), an oxidative metabolite of cortisol. The ratio of 6β-OHF to 17-hydroxycorticosteroids (17-OHCS) in urine was measured before, during, and after treatment with famotidine and cimetidine for 3 days in a cross-over study. The ratio was decreased by 25% -35% of the original level after 1-3 days of oral treatment with cimetidine (800 mg, b. i. d.). The reduction vanished within 2 days after the last dose of cimetidine. The ratio was not significantly changed during oral treatment with famotidine (40 mg, b. i. d.). These findings indicate that famotidine, in contrast to cimetidine, does not affect the hepatic oxidative metabolism of cortisol in man, and it is suggested that famotidine does not affect the hepatic drug-metabolizing capacity in humans.
