Slow-release oxprenolol compared with oxprenolol in hypertensive patients: a multicenter clinical trial

Oxprenolol (OX) is a nonselective, beta-adrenergic blocking agent with intrinsic sympathomimetic activity. We studied 178 patients in five centers to determine whether a polymer-matrix-based, slow-release preparation of oxprenolol (SR-OX) given once daily was as effective as the standard preparation given twice daily for the treatment of patients with mild to moderate hypertension. After a placebo washout phase, patients were treated with OX until blood pressure was controlled. They were then randomized in a double-blind fashion to continue the same dose, given as either OX bid or SR-OX qd with a placebo as the second dose. All patients took hydrochlorothiazide 50-100 mg/d throughout the study. Blood pressure was reduced 23/15 mm Hg (p less than 0.001) and pulse 8 beats/min in the SR-OX group (n = 67) and 24/17 mm Hg (p less than 0.001) and 8 beats/min in the OX group (n = 72) by titrating standard OX. After randomization to SR-OX or OX, there were no further changes over six weeks. Home-determined blood pressures showed no loss of control in the evening. There were no unexpected adverse effects. We conclude that SR-OX given once daily is as effective as OX given twice daily for the treatment of hypertension.