Effect of efonidipine and ACE inhibitors on proteinuria in human hypertension with renal impairment

Background: Although several lines of recent studies fail to demonstrate the beneficial action of calcium antagonists, a novel dihydropyridine efonidipine, which possesses dilatory action of both afferent and efferent arterioles and, therefore, shares the renal microvascular action with angiotensin converting enzyme (ACE) inhibitors, is reported to exhibit renal protection in experimental animals. Methods: The present study evaluated the effect of efonidipine and ACE inhibitors on blood pressure (BP) and proteinuria. Sixty-eight hypertensive patients with renal impairment (serum creatinine, > 1.5 mg/dL) or chronic renal parenchymal disease were randomly assigned to efonidipine or ACE inhibitor treatment. Of the 68 patients, 23 were treated with efonidipine and 20 with ACE inhibitors; these patients were analyzed for the 48-week study. Results: Both efonidipine and ACE inhibitors produced a similar degree of reductions in BP (efonidipine, from 161 ± 2/93 ± 2 to 142 ± 5/82 ± 2 mm Hg; ACE inhibitor, from 163 ± 3/95 ± 2 to 141 ± 5/83 ± 2 mm Hg), and maintained creatinine clearance for 48 weeks. Proteinuria tended to decrease in both groups, and a significant reduction was observed in proteinuric patients (> 1 g/day) (efonidipine, from 2.7 ± 0.3 to 2.1 ± 0.3 g/day; ACE inhibitor, from 3.0 ± 0.4 to 2.0 ± 0.5 g/day). Of interest, efonidipine decreased proteinuria in proteinuric patients who failed to manifest decreases in systemic BP. Finally, the incidence of adverse effects, including hyperkalemia and cough, was less in the efonidipine-treated group. Conclusions: Both efonidipine and ACE inhibitors preserved renal function in hypertensive patients with renal impairment. The antiproteinuric effect was apparent in patients with greater proteinuria. The beneficial action of efonidipine, along with fewer side effects, may favor the use of this agent in the treatment of hypertension with renal impairment.