Antihypertensive response to ketanserin: influence of race and weight.

The antihypertensive effects of the 5-HT2 receptor antagonist ketanserin were evaluated in 16 patients with uncomplicated essential hypertension. Following a three week single-blind placebo treatment period, patients were randomized to receive in a double-blind manner oral ketanserin 20 mg or 40 mg twice a day for 10 weeks. In the racially mixed patient population, mean (+/- SD) seated blood pressure 12 hours after the last dose of placebo was 161 +/- 11/99 +/- 9 mm Hg and 155 +/- 19/98 +/- 10 mm Hg after ketanserin (P greater than .05). Ketanserin 20 mg twice a day did not lower blood pressure significantly. In contrast, 40 mg twice a day significantly decreased systolic blood pressure (P less than .02), and lowered diastolic blood pressure (P = .06). White patients (N = 7) showed a significant decrease in blood pressure (BP) with ketanserin treatment (158 +/- 5/98 +/- 8 vs. 147 +/- 13/92 +/- 6 mm Hg, P less than .05) while black patients (N = 9) did not (165 +/- 13/100 +/- 9 vs. 161 +/- 21/102 +/- 10 mm Hg, P greater than .05). For black patients only, significant correlations were observed between body weight and the change in diastolic BP (r = -.86, P less than .005). The racial difference in response to ketanserin could not be attributed to differences between the two groups in age, sex, body weight, pretreatment blood pressure or ketanserin dose. The nature of the racial difference in the chronic antihypertensive response to ketanserin warrants further evaluation.