Optimal therapeutic regimen of famotidine based on plasma concentrations in patients with chronic renal failure.

An oral therapeutic regimen of famotidine, a histamine H2-receptor antagonist, was evaluated in patients with chronic renal failure who were receiving dialysis three times a week. Measurements of the half-life, bioavailability, and dialysis elimination rate were performed. The half-life of famotidine after oral administration in patients with renal failure was 22.5 hours as opposed to 2.5 hours in control subjects: after intravenous injection, it was 14.6 hours as compared with 2.2 hours. The bioavailability after oral administration was 49.4% in patients with renal failure and 55.2% in control subjects. The dialysis elimination rate was stable and independent of its plasma level, with an average of 41.9%. The oral administration of famotidine (20 mg) immediately after dialysis (60 mg/week) was found optimal and safe. There were no significant side effects with this regimen.