Renal Effects of Nicardipine, a Calcium Entry Blocker, in Hypertensive Type II Diabetic Patients With Nephropathy

We studied the renal effects of nicardipine, a calcium entry blocker, in eight patients with essential hypertension (group A, WHO I or II), six hypertensive type II diabetics with mild-to-moderate nephropathy (group B, urinary albumin 200–789 mg/day), and six hypertensive type II diabetics with severe or advanced nephropathy (group C, urinary albumin 1,596–4,300 mg/day). The patients received an intravenous dose of nicardipine hydrochloride (0.5 mg) or saline placebo in a random order. Glomerular filtration rate (GFR) and renal blood flow (RBF) were measured by means of thiosulfate sodium and p-aminohippurate, respectively, during the 30 min after the nicardipine or saline injection. Blood pressures were serially monitored during the study. Nicardipine reduced both systolic and diastolic blood pressures significantly (P < .05 to .01) at all measurement periods in all study groups compared with the respective placebo. Nicardipine increased RBF (P < .01), GFR (P < .05), and urinary Na⁺ excretion (P < .01) and decreased total renal vascular resistance (P < .01) in groups A and B, but these parameters remain unchanged in group C. The filtration fraction remained unaltered in all groups. The results indicate that nicardipine has several favorable renal effects with a concomitant hypotensive action in hypertensive type II diabetics with mild-to-moderate nephropathy, as observed in patients with uncomplicated essential hypertension, and the renal pharmacological responsiveness appears to be related to the severity of nephropathy. Nevertheless, nicardipine can be a useful agent in lowering blood pressure without deteriorating renal function in hypertensive type II diabetics with advanced nephropathy.