Sustained
proteinuria is an important risk factor for not only renal but also cardiovascular morbidity and mortality. Although inhibitors of the renin-angiotensin system (RAS) have been shown to reduce
proteinuria. Monotherapy with those drugs is often insufficient for optimal blood pressure (BP)-lowering and therefore, combined
therapy is needed. Recent reports suggested that
cilnidipine, a dual L-/
N-type calcium channel blocker, has renoprotective effect by dilating both efferent and afferent arterioles. In this study, a multicenter, open, randomized trial was designed to compare the antiproteinuric effect between
cilnidipine and
amlodipine when coupled with RAS inhibitors in hypertensive patients with significant
proteinuria.
Proteinuria was evaluated by 24-h home urine collection for all patients. A total of 35 proteinuric (>0.1 g/day) patients with uncontrolled BP (>135/85 mmHg) were randomized to receive either
cilnidipine (n = 18) or
amlodipine (n = 17) after a 6-month treatment with RAS inhibitors and were followed for 48 weeks. At baseline, the
cilnidipine group was older and had lower body mass index (BMI) compared to the
amlodipine group. After 32 weeks of treatment, diastolic blood pressure (DBP) was slightly, but significantly reduced, in the
cilnidipine group, although systolic blood pressure (SBP) and mean BP did not differ. The urinary
protein did not differ at baseline (
cilnidipine group 0.48 g/day,
amlodipine group 0.52 g/day); however, it significantly decreased in the
cilnidipine group (0.22 g/day) compared to the
amlodipine group (0.50 g/day) after 48 weeks of treatment. Our findings suggest that
cilnidipine is superior to
amlodipine in preventing the progression of
proteinuria in hypertensive patients even undergoing treatment with RAS inhibitors.