Antiproteinuric effect of an N-type calcium channel blocker, cilnidipine

The objective of the present study was to determine antiproteinuric effect of an N-type calcium channel blocker - cilnidipine. Subjects were 43 essential or renal hypertensive subjects who had been taking calcium channel blockers other than cilnidipine for at least 6 months. All patients had proteinuria greater than 0.2 g/day in spite of fair blood pressure control (< 150/90 mmHg). Calcium channel blockers in 25 patients (62 ± 3 years) were switched to cilnidipine (cilnidipine group), whereas other 18 patients (58 ± 3 years) continued to take originally prescribed calcium channel blockers (control group). The 24-hr urine collections were done at baseline and after 6 months of the follow-up period. Baseline characteristics including age, blood pressure levels, body mass index and creatinine clearance were similar between cilnidipine and control groups. Urinary protein excretion also was comparable between cilnidipine (0.61 ± 0.10 g/day) and control (0.86 ± 0.17 g/day) groups. Urinary protein significantly decreased after 6 months in cilnidipine group (-0.21 ± 0.11 g/day, -36%, p < 0.01), whereas it did not change in control group (+0.01 ± 0.15 g/day, 0.4%, ns). There were no significant changes in blood pressure, serum creatinine, creatinine clearance, estimated protein intake, and urinary salt excretion during the follow-up period in either group. The reduction of urinary protein by cilnidipine was evident in essential hypertensives (-54 ± 9%, n = 18, p < 0.01) but not in renal hypertensives (+10 ± 35%, n = 7, ns). Results suggest that cilnidipine has an antiproteinuric effect especially in patients with essential hypertension.