Comparative efficacy of captopril and atenolol in moderately severe essential hypertension.

A randomized, double-blind study was undertaken to compare atenolol and captopril as second-step agents in the treatment of essential hypertension resistant to 5 mg bendrofluazide daily. Using a cross-over technique 28 patients were administered each drug sequentially for periods of 8 weeks with an intervening washout period of 2 weeks. Both drugs produced a significant reduction in both systolic and diastolic blood pressure (P less than 0.01). Captopril was more effective than atenolol at reducing diastolic pressure (P less than 0.05), but there was no significant difference in the systolic pressure. Neither drug produced side effects of a serious nature, but untoward symptoms were more frequent with atenolol. The effect of the drugs on myocardial function was assessed by comparing pre-treatment with post-treatment left ventricular ejection fractions, both at rest and with exercise, measured by MUGA scan. The resting ejection fraction was unaffected by either drug. During exercise, on captopril, the ejection fraction showed the normal increase over the resting baseline, but on atenolol there was no such increase.