Combined effect of hydrochlorothiazide and atenolol in antihypertensive therapy on 42 patients

Forty-two patients with mild to moderate cssential hypertension were randomly divided int0 3 groups. Group A was treated orally with hydrochlorothiazide (HCT) 25 mg bid in the lst phase of 3 wks and atenolol 100 mg qd in the 2nd phase of 3 wks. In the 3rd phase of 3wks a combination of HCT and atenolol was given. Group B was treated with drugs in the sequence of atenolol, HCT. and combination of the 2 drugs, respectively for same courses. Group C was given the combination throughout the 3 phases. Results: Atenolol was superior to HCT in lowering blood pressure with a higher response rate(79%). and the combination of atenolol and HCT showed still higher efficacy (86%) than HCT. The % of efficacy of the combined therapy was quite close to the additive effect. The hypotensive action of the combined therapy was independent of the sequence of these drugs. The effects of the combined therapy on heart rate, sodium and potassium in blood and urine were more favorable than that given by any of the monotherapy used in this trial. We concluded that the combination of HCT and atenolol would be recommended as a basic regime in the treatment of mild to moderate hypertension.