Comparison of ketanserin and slow-release nifedipine added to the treatment of hypertensive patients uncontrolled by a thiazide diuretic plus beta-adrenoceptor blocker.

1. Ketanserin or slow-release nifedipine were added to the treatment of 24 patients with hypertension uncontrolled by a thiazide diuretic plus beta-adrenoceptor antagonist in an observer-blind, randomised parallel-group study of 6 months duration. 2. At 6 months the mean falls in supine blood pressure were for ketanserin (mean daily dose 77 mg) 7/5 mm Hg and for nifedipine (mean daily dose 62 mg) 27/10 mm Hg. The difference between the treatments was significant for systolic blood pressure (P less than 0.02) and mean arterial pressure (P less than 0.05). Six nifedipine-treated patients reached target blood pressure, compared with one patient with ketanserin (P less than 0.02). 3. One patient taking nifedipine, and none taking ketanserin withdrew because of side-effects. The tolerability of the two drugs was broadly similar. 4. Ketanserin treatment was associated with significant changes in supine pulse rate (-8 beats min-1, P less than 0.05) and corrected QT interval (+27 ms, P less than 0.05). Nifedipine treatment had no effect on these variables. The change in pulse rate was significantly different between the groups. 5. In patients treated with a diuretic and beta-adrenoceptor blocker who required additional treatment ketanserin was significantly inferior to nifedipine.