Effect of nitrendipine on renal function in renal-transplant patients treated with cyclosporin: a randomised trial

Background Calcium antagonists such as nitrendipine reduce the effects of c yclosporin on renal haemodynamics, however, their long-term efficacy has no t been established. We did a randomised trial to investigate the effects of nitrendipine on renal function in renal-transplant patients treated with c yclosporin. Methods 253 renal-transplant patients were recruited: 52 normotensive patie nts (diastolic blood pressure <90 mm Hg) were assigned placebo and 57 nitre ndipine 5 mg twice daily; 71 hypertensive patients (diastolic blood pressur e >90 to <115 mm Hg) were assigned placebo and 73 nitrendipine 10 mg twice daily. Nitrendipine was increased to 20 mg twice daily if the target diasto lic blood pressure (<90 mm Hg) was not achieved. The patients were seen onc e a month for 24 months; blood pressure and serum creatinine concentration were recorded at each visit. Analysis was by intention to treat. Findings 63 patients were withdrawn (35 nitrendipine, 28 placebo). The mean serum creatinine concentration at baseline was slightly higher in the nitr endipine group (146.7 mu mol/L [SE 4.42]) than in the placebo group (137.0 mu mol/L [3.54]. At the 24-month endpoint or at dropout, serum creatinine c oncentration was significantly higher in the 123 patients in the placebo gr oup than the 130 patients in the nitrendipine group (160.8 [7.1] vs 148.5 [ 5.3], p for effect of treatment=0.025, analysis of covariance in a two-way classification; 95% CI for difference -1.77 to -22.98). At study entry, the blood pressures of the placebo and the nitrendipine groups were almost ide ntical. At 24 months, blood pressure was higher in the normotensive patient s given a placebo than in those patients given nitrendipine. By contrast, b lood-pressure values were similar in those hypertensive patients given a pl acebo and those given nitrendipine at the end of treatment. Interpretation The calcium antagonist nitrendipine has no adverse effects o n kidney function In renal-transplant patients with cyclosporin. The drug h as a small but significant nephroprotective effect, that is independent of the drug's antihypertensive action.