Pressure and humoral changes induced by atenolol and hydrochlorothiazide + amiloride, alone and in free combination. A comparative between-patient study.

The authors have performed a between-patient study in 76 patients with mild or moderate essential arterial hypertension, with the aim of comparing the results of atenolol 100 mg daily, hydrochlorothiazide 50 mg + amiloride 5 mg 1 tablet daily, and the combination of the above two agents at the same daily doses. Thirty-one patients received the free combination diuretic-beta-blocker throughout the study period; 26 patients non-responders to atenolol 100 mg daily (supine diastolic blood pressure greater than 90 mmHg) after a one-month treatment period received the above combination for a further four months; and 19 patients non-responders to hydrochlorothiazide 50 mg + amiloride 5 mg, 1 tablet daily, after a one-month treatment period received the above combination for a further four months. In the patients who were non-responders to either atenolol or the diuretic, supine and upright blood pressure showed a further and clinically consistent decrease as a result of the combination therapy. A similar consistent decrease was seen in the patients receiving the combination therapy throughout the study. Plasma levels of glucose, urea, creatinine, sodium, potassium and uric acid were not modified either by the single agents or during administration of the combination therapy. In particular, plasma potassium concentration did not show any statistical or clinical changes. Any side-effects were of little clinical importance and never required discontinuation of therapy. In conclusion, atenolol combined with hydrochlorothiazide + amiloride (100 mg + 50 mg + 5 mg) provides an effective and well tolerated blood pressure control in most patients with mild or moderate arterial hypertension, including non-responders to diuretic or beta-blocker alone.