Clinical aspects during therapy with the serotonin antagonist ketanserin

Ketanserin, a selective S2-serotoninergic antagonist with an additional alpha 1-receptor-blocking effect and a central component of action, represents a new type of antihypertensive drug. It decreases blood pressure by reducing total peripheral resistance. Cardiac output and heart rate remain practically unaltered. The antihypertensive effect of 2 x 20 to 2 x 40 mg/day corresponds to that of therapeutic doses of metoprolol, nifedipine, hydrochlorothiazide or captopril. The main subjective side effects are somnolence, dizziness and dryness of the mouth. No serious metabolic side effects have been observed. Ketanserin can lead to a prolongation of the QTc interval and therefore should not be given to patients with preexisting QTc prolongation, atrioventricular or sinoauricular block of higher degree or with severe bradycardia (less than 50/min). If a diuretic is to be prescribed simultaneously, it must contain a potassium-sparing component. Since its antihypertensive effect is more pronounced in older age, ketanserin should preferentially be given to patients over 60 years of age.