Twice-daily pindolol and alprenolol in essential hypertension of moderate severity

A double-blind cross-over comparison of the antihypertensive actions of alprenolol and pindolol in equipotent doses was carried out in 22 patients with moderately severe essential hypertension. No other drugs were allowed. Ten patients were in WHO grade I, and 12 in grade II. The average initial pressures, similar after both the first and second 4-week placebo periods, were 175/116 mm Hg standing and 175/109 mm Hg supine. These pressures were decreased significantly by each beta-blocking drug, and about equally in both positions. An average reduction, using both 2-month treatment periods, was -13/-7 mm Hg with alprenolol, and with pindolol it was -23/-13 mm Hg. Both systolic and diastolic normotension (less than 160/100) in the supine position occurred in 45% of the patients when treated with alprenolol and in 64% with pindolol. With diastolic normotension alone the figures were 59% and 82% respectively. Rather low daily doses of 400 mg alprenolol and 20 mg pindolol were effective; increasing the doses to the average final levels of 533 mg alprenolol and 25 mg pindolol resulted in just negligible further pressure reductions. There were no serious side effects or complete resistance. Pindolol reduced the resting heart rate significantly in spite of its intrinsic sympathomimetic activity. Two aspects emerging from this study have clear practical implications. The twice-daily dosage, used here purposefully, of both alprenolol and of pindolol reduces effectively blood pressure, and increases patient convenience. Heat failure was not induced even in those 12 patients with cardiac involvement, including 5 with clear-cut radiological left ventricular enlargement.