Chronic 5-HT2-receptor blockade by ritanserin does not reduce blood pressure in patients with essential hypertension

The selective 5-HT2-receptor-blocking agent ritanserin is an analogue of the antihypertensive agent ketanserin. By evaluating the antihypertensive effects of ritanserin the aim of this investigation was to indirectly elucidate the mechanism of action of ketanserin. Thirteen patients with essential hypertension were treated with placebo and ritanserin, 10 mg b.i.d., in a double-blind, cross-over design (4-week periods). At the end of the treatment periods blood pressure as well as plasma concentrations of ritanserin were evaluated for 24 hours. Despite high steady state and peak plasma concentrations of ritanserin the compound did not lower the blood pressure compared with placebo. Since chronic selective 5-HT2-receptor blockade by means of ritanserin did not lower the blood pressure, it is concluded that the 5-HT2 blocking properties of ketanserin cannot alone be responsible for the antihypertensive effects of ketanserin.