RENAL AND HEMODYNAMIC-EFFECTS OF AMLODIPINE AND NIFEDIPINE IN HYPERTENSIVE RENAL-TRANSPLANT RECIPIENTS

Background. Immunosuppressive treatment with cyclosporin A (CsA) impro ves the survival of renal allografts, but is associated with renal vas oconstriction and hypertension. Previous reports suggest that the calc ium-channel blockers nifedipine and amlodipine may improve graft funct ion in CsA-treated patients. We have compared the effects of amlodipin e (5-10 mg once daily) and nifedipine retard (10-40 mg twice daily) on renal function and blood pressure in renal transplant recipients trea ted with CsA. Methods. This was a multicentre, two-way, crossover stud y in 27 evaluable hypertensive patients with renal insufficiency follo wing renal transplantation, who were maintained on a stable dose of Cs A. Patients received either amlodipine (5-10 mg once daily) or nifedip ine retard (10-40 mg twice daily) for 8 weeks, and were then crossed o ver to the other treatment for a further 8 weeks. Results. Trends were seen during amlodipine treatment towards larger improvements, in seru m creatinine (by 8% of baseline on amlodipine vs 4% on nifedipine), li thium clearance (13% vs 2%), and glomerular filtration rate 11% vs 7%) . Effective renal plasma flow was increased by 11% of baseline on nife dipine vs 9% on amlodipine. There were no significant differences betw een treatments. Amlodipine and nifedipine lowered systolic blood press ure to a similar extent (21 mmHg vs 15 mmHg respectively, P=0.25), but amlodipine was more effective than nifedipine in lowering diastolic b lood pressure (13 mmHg vs 8 mmHg, P=0.006). Both treatments were well tolerated. Conclusion. Once-daily amlodipine is at least as effective as twice-daily nifedipine retard in controlling blood pressure and doe s not adversely affect graft function in hypertensive renal allograft recipients.