Atenolol improves blood pressure control in patients taking captopril and frusemide.

In a double-blind randomised cross-over study atenolol 100 mg daily and matching placebo were given to 14 patients whose blood pressure (BP) was uncontrolled on a fixed dose of captopril and frusemide. Atenolol produced a further reduction in both supine (170/105 mmHg to 163/94 mmHg) and standing (171/114 mmHg to 160/96 mmHg) BP and a significant fall in pulse rate and plasma renin activity (PRA). This fall in BP showed a highly significant correlation with pre-treatment plasma renin levels. No adverse side effects were encountered during the study. Previous suggestions that beta-blockade had no additional hypotensive effect in patients receiving captopril were not substantiated. For patients whose BP was poorly controlled with captopril and a diuretic, a selective beta-blocker is suggested as a useful third line agent.