Mechanism of antihypertensive action of ketanserin in man.

A randomised double blind crossover study was carried out to determine whether ketanserin, a serotonin antagonist with an antihypertensive action in animals, has an alpha 1 adrenergic mediated antihypertensive effect in man. Steady state plasma ketanserin concentrations (mean 88 (SD 19) micrograms/1) and cardiovascular responses measured in five healthy volunteers showed that therapeutic doses of ketanserin significantly antagonised the alpha 1 receptor mediated increase in arterial blood pressure after treatment with methoxamine. Thus the antihypertensive action of ketanserin in man appears to originate from a blockade of peripheral vascular alpha 1 receptors.