Background: Immunosuppressive treatment with cyclosporin A (CsA) improves the survival of renal allografts, but is associated with renal vasoconstriction and hypertension. Previous reports suggest that the calcium-channel blockers nifedipine and amlodipine may improve graft function in CsA-treated patients. We have compared the effects of amlodipine (5-10 mg once daily) and nifedipine retard (10-40 mg twice daily) on renal function and blood pressure in renal transplant recipients treated with CsA.
Methods: This was a multicentre, two-way, crossover study in 27 evaluable hypertensive patients with renal insufficiency following renal transplantation, who were maintained on a stable dose of CsA. Patients received either amlodipine (5-10 mg once daily) or nifedipine retard (10-40 mg twice daily) for 8 weeks, and were then crossed over to the other treatment for a further 8 weeks.
Results: Trends were seen during amlodipine treatment towards larger improvements, in serum creatinine (by 8% of baseline on amlodipine vs 4% on nifedipine), lithium clearance (13% vs 2%), and glomerular filtration rate 11% vs 7%). Effective renal plasma flow was increased by 11% of baseline on nifedipine vs 9% on amlodipine. There were no significant differences between treatments. Amlodipine and nifedipine lowered systolic blood pressure to a similar extent (21 mmHg vs 15 mmHg respectively, P=0.25), but amlodipine was more effective than nifedipine in lowering diastolic blood 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 does not adversely affect graft function in hypertensive renal allograft recipients.