Blockade of 5-HT2 receptors as a mechanism of antihypertensive action of ketanserin

Ketanserin is a selective 5-HT2-receptor antagonist. The drug blocks 5-HT2-mediated effects of serotonin on blood vessels and platelets, both in experimental animals as well as in humans. Ketanserin is a useful antihypertensive drug especially in elderly patients. Its precise mechanism of antihypertensive action in humans is unknown. This effect cannot be only explained by 5-HT2- or alpha1-receptor antagonistic properties (higher doses) of the drug. Ketanserin may also be used in the treatment of some peripheral vascular diseases (e.g. Raynaud's phenomenon) as well as of carcinoid syndrome. The drug has a few, usually mild side effects. The usual dosage of ketanserin in the treatment of hypertension or vasospastic diseases is 40 to 80 mg per day, in two divided doses. Doses higher than 80 mg per day should be avoided, because of the side effects, therapeutic efficacy remaining unchanged.