A diuretic is more effective than a beta-blocker in hypertensive patients not controlled on amlodipine and lisinopril

The combination of an angiotensin-converting enzyme inhibitor and a calcium antagonist has a synergistic effect in patients with more severe hypertension. However. when this combination fails to control blood pressure, it is not clear which drug is then additive. The aim of this work was to study in a double blind; randomized, crossover design the effect on blood pressure of the addition of either a thiazide diuretic (bendrofluazide, 5 mg once daily) or a beta-blocker (atenolol, 100 mg once daily) or placebo each for a month in hypertensive patients who are not adequately controlled on the combined treatment of amlodipine 5 mg once daily and lisinopril 5 mg twice daily. Eighteen patients with a supine diastolic pressure of more than 90 mm Hg after at least 1 month on the combined treatment of amlodipine and lisinopril were enrolled in the study. The results show thar in patients whose blood pressures are not controlled by the combination of amlodipine and lisinopril, the addition of bendrofluazide 5 mg once daily causes a significant fall in blood pressure compared with placebo and a significantly greater fall than 100 mg atenolol once daily.