Systemic and Regional Hemodynamic Effects of Gallopamil in Patients with Essential Hypertension

Systemic and regional hemodynamics were assessed in 10 patients with uncomplicated mild to moderate essential hypertension before and during gallopamil therapy. Cardiac output was measured in triplicate with indocyanine dye. Plasma volume and renal blood flow were measured radioisotopically. Immediately following the initial dose of a slow-release (SR) formulation of gallopamil, a significant fall in arterial pressure associated with a decreased total peripheral resistance and a reflex increase in heart rate and cardiac output were seen. Then, after 8–12 weeks of treatment, arterial pressure and total peripheral resistance remained reduced, but heart rate and cardiac output returned to pretreatment levels. Gallopamil also produced significant reductions in renal and splanchnic vascular resistance. Plasma volume and total blood volume did not change. Thus, gallopamil reduced arterial pressure and vascular resistances without fluid retention or prolonged reflexive changes.