Moderate essential hypertension control: a double-blind crossover study between a serotonin antagonist and a post-synaptic alpha-blocker.

The purpose of this study was to compare the effects of the serotonin antagonist ketanserin and the post-synaptic alpha-blocker prazosin on blood pressure in patients with essential hypertension. Both drugs lower blood pressure by a reduction in total peripheral vascular resistance and by reducing the pre- and afterload, apparently achieving these haemodynamic effects through different mechanisms. Ketanserin appears to have a greater effect on afterload. Six men and four women (mean age 47.2 years) with diastolic blood pressure greater than or equal to 100 mmHg were treated for 4 weeks with placebo and then randomized and treated for 8 weeks double-blind with either ketanserin or prazosin. A 4-week wash-out phase with placebo was then instituted followed by another 8 weeks of treatment in a crossover fashion with either ketanserin or prazosin. Blood pressure was measured on each occasion in the supine, sitting and standing positions. The results showed that both medications significantly lowered blood pressure (computed sitting values for all patients: ketanserin from 177/104 +/- 5/7 to 158/89 +/- 8/5 mmHg; prazosin from 176/103 +/- 11/8 to 156/88 +/- 6/4 mmHg). The data in this study show that ketanserin as an antihypertensive agent is as effective as prazosin, but in contrast requires no titration of dosage and better compliance can be expected with twice daily rather than three times daily dosing.