Haemodynamic and humoral responses to chronic ketanserin treatment in essential hypertension.

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Abstract
Ketanserin (120 mg/day) or placebo was given orally to 14 patients with mild to moderate essential hypertension according to a double-blind crossover protocol, each treatment period lasting 6 wk. Resting intra-arterial pressure in the recumbent position was reduced from 150/84 to 141/77 mm Hg; the hypotensive effect persisted throughout an uninterrupted graded exercise test to the point of exhaustion. The hemodynamic effects were similar at rest and during exercise. Overall, systemic vascular resistance decreased by 14%, heart rate fell by 5%, but stroke volume and cardiac output increased. Mean pulmonary arterial pressure and capillary wedge pressure were not significantly affected, but pulmonary vascular resistance decreased by 15%. The pressor response to methoxamine was significantly reduced by ketanserin. Both plasma noradrenaline [norepinephrine] and adrenaline [epinephrine] concentrations increased, plasma renin activity and angiotensin II concentration decreased and plasma aldosterone concentration was unchanged. Evidently, ketanserin induces arteriolar dilatation, possibly related to an .alpha.-1-antagonistic action and to a reduced circulating angiotensin II concentration. The hemodynamic response is complex, and an increase in cardiac output limits the hypotensive effect. There is no firm evidence of an effect on venous tone as cardiac filling pressures do not change.