Cardiovascular effects of ketanserin during cold pressure and during isometric and dynamic exercise in hypertensive patients.

Ketanserin is an arteriolar vasodilator, acting on serotoninergic (5-HT2) and adrenergic (alpha 1) receptors. In animals, ketanserin exerts a centrally mediated inhibition of sympathetic nerve activity. In humans it is not established whether ketanserin reduces basal or reflex increases in sympathetic outflow. In different groups of patients, we have investigated the cardiovascular response as well as plasma noradrenaline (pNA) during rest, during the cold pressure test (0 degree C for 3 min), and during isometric (handgrip), and/or dynamic exercise in order to see whether ketanserin reduces the normal increase in sympathetic tone during these maneuvers. Twenty-one patients with essential hypertension were given oral ketanserin (40 mg) once or twice daily for 4 weeks after a 2-4-week single-blind control period. Ketanserin significantly lowered systolic and diastolic blood pressure as well as heart rate during rest. Resting pNA was not significantly reduced, but the change in pNA was significantly correlated to the reduction in blood pressure and heart rate. During exercise, blood pressure and heart rate remained reduced. Moreover, the relative increase in systolic blood pressure during handgrip and the relative increase in heart rate during bicycle ergometry were significantly reduced during ketanserin therapy. During isometric exercise the relative reduction in blood pressure was significantly correlated to the relative reduction in pNA.