Cimetidine or ranitidine in renal transplant patients receiving cyclosporine.

While H2-receptor antagonists are commonly used in renal transplant patients to prevent peptic ulcer disease, they have been associated with immunostimulation, interference with cyclosporine (CsA) metabolism, and inhibition of tubular secretion of creatinine. In renal transplant patients, cimetidine in high doses has been shown to cause a sustained rise in serum creatinine (SCr) and to reduce creatinine clearance (CrCl) with no change in inulin clearance. In this short-term prospective study, we evaluated the effects of single daily doses of cimetidine or ranitidine on renal function, and CsA serum concentration. Fourteen renal transplant patients with stable renal function were assigned to receive either cimetidine 400 mg daily or ranitidine 150 mg daily for 7 days. In patients who received cimetidine, a slight rise in SCr was observed at days 2 and 5 which was not statistically significant, but no significant change in CsA trough level was noted. No changes in SCr or CsA level were noted in the patients who received ranitidine. No changes in GFR were observed in either cimetidine- or ranitidine-treated patients. We conclude that, in our short-term study, cimetidine or ranitidine in the doses used in this study did not affect the GFR or CsA level, or SCr.