Effects of Chronic Antihypertensive Treatment with Ketanserin Versus Metoprolol on Blood Pressure and Large Arteries' Compliance in Humans: A Cross‐Over Double‐Blind Study

The antihypertensive efficacy of a serotonin-receptor antagonist, ketanserin, was compared with that of a well-established antihypertensive drug, metoprolol, and their cardiac and forearm hemodynamic effects were investigated using echocardiography and bidimensional pulsed Doppler flowmetry, respectively. Twenty hypertensive subjects completed a double-blind, cross-over, randomized study using ketanserin and metoprolol. Two 5-week courses with ketanserin or metoprolol were preceded by a placebo period; the total duration of the study was 15 weeks. Despite a comparable efficacy in reducing systolic and diastolic blood pressure (about 10% of the basal value), the two drugs showed quite different effects on forearm hemodynamics. Ketanserin increased forearm blood flow and induced a significant decrease in forearm vascular resistance (from 141 +/- 16 to 75 +/- 11 mm Hg/mL/sec, P less than .01). Furthermore, this treatment was able to improve brachial artery compliance (from 1.89 +/- .3 to 3.2 +/- .3 cm4/dyne 10(-7), P less than .01). On the contrary, metoprolol did not modify forearm hemodynamics. Both drugs did not significantly modify cardiac performance, as evaluated by left ventricle circumferential fiber shortening. Cardiac output was increased by ketanserin (from 5.9 +/- .3 to 6.6 +/- .5 L/min, P less than .05) and fell during treatment with metoprolol (from 5.9 +/- .4 to 4.9 +/- .3 L/min P less than .01). Thus, the two drugs reduce blood pressure through different hemodynamic mechanisms and the effects of ketanserin on systemic and peripheral circulation seem more favorable.