Cardiovascular effects of verapamil in essential hypertension.

Calcium antagonists may affect the regulation of body sodium and adrenergic-dependent mechanisms. Exchangeable sodium, blood volume, plasma norepinephrine, renin, aldosterone, pressor responsiveness to norepinephrine, heart rate responses to isoproterenol, and lipid metabolism were studied in 15 patients with essential hypertension after 8 weeks of treatment with verapamil (348 +/- 68 (SD) mg/day). Supine blood pressure decreased from 153/103 +/- 19/12 mm Hg to 140/95 +/- 14/12 mm Hg (P less than 0.01). Exchangeable sodium, blood volume, plasma norepinephrine, renin and aldosterone, serum total cholesterol, the lipoprotein fractions, and apoprotein levels were unchanged. The norepinephrine pressor and the isoproterenol chronotropic doses tended to increase, whereas the dose-response curve of blood pressure related to plasma norepinephrine was significantly displaced to the right (F = 5.34; P less than 0.05). The antihypertensive effect of verapamil is associated with a decreased cardiovascular pressor responsiveness to norepinephrine without changes in endogenous noradrenergic activity. Moreover, verapamil does not modify the sodium/fluid volume state, the activity of the renin-angiotensin aldosterone axis, or lipid metabolism.