Effects of indenolol on blood pressure, lower limb blood flow, adrenergic reflexes, and plasma renin activity

The antihypertensive effects of indenolol, a new not-cardioselective beta-blocking agent, were evaluated in patients with WHO grades I and II essential hypertension (range 160/95 to 200/115 mm Hg) in a double-blind, placebo-controlled study after acute (12 patients) and 2-week treatment (seven patients). Indenolol (30 to 120 mg) reduced blood pressure in a dose-dependent fashion. Maximum reduction was 26 mm Hg for systolic and 17 mm Hg for diastolic pressure. Hypotensive activity commenced within 10 minutes, peaked in 60 minutes, and persisted for about 7 hours. Lower limb vascular resistance (strain-gauge plethysmography) was significantly lowered, thus suggesting an intrinsic sympathomimetic activity. Heart rate was progressively reduced at 30 and 60 mg without any additional effect at 120 mg. Indenolol did not alter adrenergic reflexes (standing, cold application, and hand-grip) and did not induce any side effect. In conclusion, indenolol possesses an antihypertensive activity associated with reduction of vascular resistance.