Effects of ketanserin on microhemodynamics and hemorheology in patients with essential hypertension.

Ketanserin, a serotonin antagonist, has recently been developed. This agent produces antihemagglutination and dilation of blood vessels. Blood pressure is also lowered by ketanserin. We investigated the effect of ketanserin on microhemodynamics and hemorheology in essential hypertension. Twenty patients with essential hypertension (8 males; 12 females; average age +/- SE-56.2 +/- 2.5 years). A single dose of 10 mg ketanserin was given orally to each patient, without breakfast, on the experiment day. Ketanserin treatment resulted in: redution in systolic and diastolic blood pressure; significant decrease in heart rate; increase in arteriole and venule internal diameters; increase in blood flow velocities and blood flow volumes; significant decreases in whole blood viscosities at high shear rate (94.5 sec-1) and at low shear rate (0.376 sec-1), with no change in plasma viscosities; significant shortening of plasma passage times; and marked decreases in blood concentrations of total protein, albumin, and globulin. These data suggest that ketanserin beneficially affects microhemodynamics and hemorheology.