Influence of nicardipine on the blood pressure at rest and on the pressor responses to cold, isometric exertion, and dynamic exercise in hypertensive patients.

The dose-response effects of a new slow-calcium-channel blocker, nicardipine, on the resting blood pressure and on the pressor responses induced by skin cold, isometric exertion, and dynamic exercise were examined in a single-blind placebo-controlled study in six male patients with stable uncomplicated essential hypertension. Nicardipine was administered orally in doses of 5 mg, 10 mg, 20 mg, and 20 mg each given three times daily consecutively for 1 week. At the end of each dose period the effects on blood pressure and heart rate at rest and during the three pressor stimuli were measured. There was a significant dose-related reduction in the resting diastolic blood pressure without change in pulse pressure, accompanied by an increase in heart rate. No postural effects on blood pressure were observed. There was a small reduction in the pressor response to hand cold, which was statistically significant at the higher doses. There was no attenuation of the increases in pressure and heart rate induced by handgrip contraction or submaximal treadmill walking at any dose of nicardipine. These results are compatible with direct relaxing effect of the drug on the smooth muscle of the arteriolar resistance vessels without substantial impairment of the sympathetic influences responsible for postural control of the systemic blood pressure or those involved in the pressor responses to the three stimuli tested.