BISOPROLOL AND ATENOLOL IN ESSENTIAL-HYPERTENSION - EFFECTS ON SYSTEMIC AND RENAL HEMODYNAMICS AND ON AMBULATORY BLOOD-PRESSURE

The acute and short-term responses to bisoprolol and to atenolol on sy stemic and renal hemodynamics and on ambulatory blood pressure (BP) we re compared in a randomized double-blind cross-over study including 14 patients with mild to moderate essential hypertension. After a 4-week placebo period, the patients received either bisoprolol (10 mg once d aily, o.d.) or atenolol (100 mg o.d.) for 4 weeks and were switched to the other drug after a new 4-week placebo period. Cardiac output (CO) was measured by Doppler echography, and renal blood flow (RBF) and gl omerular filtration rate (GFR) were measured by constant infusion tech niques using [I-123]iodohippurate and [Cr-53]EDTA, respectively. Bisop rolol and atenolol decreased diurnal and nocturnal blood pressure (BP) . Both drugs decreased heart rate (HR) and BP both acutely and after 4 weeks. During short-term treatment, CO was maintained with bisoprolol but reduced by atenolol (by 17%). RBF decreased after the first drug intake (by 9 and 12%, respectively) but returned to its baseline value after 4 weeks, so that calculated renal vascular resistance (RVR) was reduced (by 12 and 15%, respectively). Overall, GFR was not affected by treatment. Bisoprolol and atenolol are effective antihypertensive a gents that preserve renal hemodynamics during short-term treatment.