Acute and chronic effects of nifedipine in arterial hypertension.

Abstract

Sublingual administration of nifedipine 10 mg to 11 patients and 20 mg to 6 patients with arterial hypertension caused a rapid and significant decrease in blood pressure in both groups. The average maximal reductions in the two groups were 21/16 mm Hg and 27/21 mm Hg. A concomitant rise in heart rate was found. Forearm blood flow showed a significant increase and the calculated vascular resistance a significant decrease 15–60 min after administration of both the 10 mg and the 20 mg doses. There was a negative correlation between basal vascular resistance and the maximal change of this parameter (r=−0.72, p<0.01). Plasma concentrations of nifedipine showed considerable individual variation, with slow absorption in some patients, which indicated failure of sublingual absorption in them. The difference between the mean plasma concentration in the two dose groups was statistically significant after 45 min. A negative correlation was present between the plasma concentration of nifedipine and the observed change in calculated vascular resistance (r=−0.74 at t=30 min). Treatment of 10 hypertensive patients with nifedipine 30–60 mg daily for 6 weeks reduced mean blood pressure from 175/115 mm Hg to 151/96 mm Hg (p<0.001). Heart rate and forearm blood flow rose, whereas the forearm vascular resistance showed a significant decrease. Side effects of a sensation of heat and reddening of face were noted in some patients. It is suggested that nifedipine may be useful both in the acute and chronic treatment of arterial hypertension.