Long-term effects of felodipine on blood pressure and renal hemodynamics in severe hypertension.

Felodipine, a dihydropyridine calcium antagonist, was used to treat eight patients with severe uncontrolled hypertension: five had essential hypertension, two had renovascular disease, and one chronic pyelonephritis. Mean blood pressure (BP) was 221 +/- 14/120 +/- 4 mm Hg despite treatment with three or more antihypertensive drugs. All patients experienced an immediate and pronounced lowering of BP after adding felodipine, which persisted during long-term treatment in combination with previous medication except for vasodilating drugs. In all cases, an increase in glomerular filtration rate (51Cr-EDTA clearance) after 6 and 12 months of felodipine treatment was seen (59 +/- 10 to 63 +/- 7 and 70 +/- 6 ml/min, respectively, p less than 0.05). Renal plasma flow (PAH clearance) exhibited only a slight increase (315 +/- 68 to 340 +/- 63 and 314 +/- 69 ml/min), giving a nonsignificant rise in filtration fraction (18 +/- 1 to 21 +/- 1 and 20 +/- 1%, respectively). It is concluded that felodipine decreases BP dramatically in patients with previously refractory hypertension and that the drug causes an improved renal function in these patients.