Hemodynamic, Renal, and Humoral Effects of the Calcium Entry Blocker Nicardipine and Converting Enzyme Inhibitor Captopril in Hypertensive Type II Diabetic Patients with Nephropathy

We compared the effect of nicardipine, a dihydropiridine derivative calcium entry blocker (CEB), with that of captopril (CAP), a converting-enzyme inhibitor (CEI), and that of the two drugs combined, on blood pressure (BP), heart rate (HR), and renal function in 12 hypertensive type II diabetic outpatients with nephropathy (persistent proteinuria >500 mg/24 h) according to a 2 × 2 factorial design. For 4-week treatments, the patients received nicardipine (NIC) 20 mg t.i.d., CAP 50 mg b.i.d., NIC plus CAP, and matched placebo. Each active treatment significantly reduced BP, with an additive effect of NIC and CAP combined versus either drug alone. HR did not change. Effective renal plasma flow (RPF) and glomerular filtration rate (GFR) were unmodified, but renal vascular resistances (RVRs) were significantly reduced by the three active treatments. Filtration fraction (FF) did not change with NIC or with NIC plus CAP and was significantly reduced with CAP. Urinary albumin excretion (UAE) was significantly reduced by each active treatment to a similar extent. Plasma renin activity (PRA) increased significantly with NIC plus CAP only and did not change when the drugs were administered singly. Plasma aldosterone, glucose, potassium, fructosamine, and urinary sodium and volume did not change during the trial. We conclude that the two drugs singly and combined are useful for treatment of hypertensive non-insulin–dependent diabetes (NIDD) patients with persistent proteinuria.