Antihypertensive Effect of Carteolol in Thiazide‐Treated Hypertensive Subjects

The antihypertensive effect of carteolol, a new potent nonselective beta‐adrenergic antagonist, was investigated in a double‐blind, parallel study of 35 patients with mild‐to‐moderate, essential hypertension whose blood pressures were not adequately controlled with a diuretic. Patients were randomly assigned to receive placebo, carteolol 5 mg, or carteolol 20 mg once a day in addition to hydrochlorothiazide 50 mg for six weeks. Thirty‐four patients completed the study: 11 patients received placebo (group 1), 12 patients received carteolol 5 mg (group 2), and 11 patients received carteolol 20 mg (group 3). After six weeks of treatment, the two groups that received carteolol had significant reductions in systolic (SBP) and diastolic (DBP) blood pressure from baseline in both the supine and standing positions. In group 2, mean SBP decreases for supine and standing positions were 11 ± 2.1 and 11 ± 1.9 mm Hg, respectively (P < .01) and 8 ± 1.2 and 9 ± 1.3 mm Hg, respectively, for DBP (P < .01); whereas in group 3, values were 8 ± 2.8 and 12 ± 3.0 mm Hg for SBP, in 5 ± 1.9 and 9 ± 3.1 mm Hg, respectively, for DBP (P < .01). The hypotensive effect was associated with slight but significant decreases in heart rate (P < .01 in group 2 andP < .05 in group 3). Reductions in SBP and DBP with the 20‐mg dose were not significantly different from those with the 5‐mg dose. With both carteolol regimens, the fall in mean blood pressure did not correlate with the initial level; but in the group taking the 5‐mg dose, it did correlate significantly with the decrease in heart rate (r = .72, P < .01). Side effects attributable to carteolol were infrequent and did not persist during continued therapy. It is concluded that carteolol, when combined with hydrochlorothiazide, is effective in reducing blood pressure in patients with mild to moderate hypertension.