Comparison of the antihypertensive effect of propranolol and practolol combined with chlorthalidone

A double blind cross-over trial of fixed doses of propranolol (640 mg/day) and the cardioselective drug practolol (1600 mg/day) was performed in 28 patients with essential hypertension whose blood pressure was not adequately controlled by chlorthalidone (100 mg 3 times weekly) alone. Chlorthalidone alone was given during the first (control) period, and it was continued throughout the propranolol and practolol treatment periods, each of 10 weeks. The systolic and diastolic blood pressures were lowered significantly by both the beta blocking drugs. The changes in blood pressure caused by altering the patient's position were the same after both beta blockers. Propranolol produced slightly lower values than practolol, but the difference was significant only for diastolic blood pressure in the sitting and supine positions. In individual patients the final blood pressure after propranolol was correlated with the final blood pressure after practolol. Only minimal side-effects of either drug were noticed. It is concluded that the doses employed both of propranolol and practolol had a good and approximately equal antihypertensive effect when combined with chlorthalidone treatment. There was no correlation between the final blood pressure and plasma renin activity.