Double-blind comparison of ketanserin with atenolol: antihypertensive activity and effect on platelet function

In a randomized double-blind study with parallel design involving 20 hypertensive patients, the antihypertensive activity and effect on platelet function of ketanserin have been compared with those of atenolol. Patients in both treatment groups were matched for age, body weight, duration of hypertension and blood pressure values on placebo. After 12 weeks of oral treatment, both ketanserin and atenolol significantly reduced blood pressure from 183/113 and 187/111 mmHg, at the end of the placebo run-in period, to 159/91 and 169/99 mmHg, respectively (P less than 0.05). No significant differences were noted between the hypotensive effect of both drugs. In contrast to ketanserin, atenolol significantly reduced the heart rate after 12 weeks of therapy (P = 0.025). Ketanserin significantly inhibited serotonin-induced platelet aggregation and serotonin uptake by thrombocytes, whereas atenolol failed to alter these variables. The results indicate that the antihypertensive activity of the serotonin antagonist ketanserin is comparable with that of the beta-receptor blocker atenolol.