Comparison of the effectiveness of a beta blocker (atenolol) and a diuretic (chlorthalidone) in black hypertensive patients

A double-blind crossover trial of atenolol and chlorthalidone was done in black Jamaican hypertensive patients. After an initial four weeks of single drug therapy, the beta blocker and thiazide diuretic were used in combination. Chlorthalidone at a daily dose of 25 mg produced a significant (P <.05) fall in the mean systolic and diastolic pressures (19.4 mm Hg and 12.2 mm Hg, respectively); atenolol produced a significant fall in the diastolic blood pressure (6.5 mm Hg); and combination therapy produced a reduction in systolic and diastolic blood pressures (27.8 mm Hg and 17.8 mm Hg, respectively). The study showed that combination therapy using a low dose of thiazide diuretic and a beta blocker was synergetic, but that a thiazide was more effective than a beta blocker in lowering the blood pressure in black hypertensive patients.