Long term treatment of moderate hypertension with penbutolol (Hoe 893d). I. Effects on blood pressure, pulse rate, catecholamines in blood and urine, plasma renin activity and urinary aldosterone under basal conditions and following exercise.

The effects of penbutolol (Hoe 893 d), a new non-selective beta-receptor blocking agent, were studied in 5 patients with moderate hypertension. Initially, it was shown that 2-4 mg given orally once or twice daily tended to lower blood pressure and pulse rate, both at rest and following submaximal work. In prolonged trials (3-8 months) 4-60 mg/day were required to produce an acceptable antihypertensive effect. Penbutolol had no effect on the normal increase in plasma noradrenaline and adrenaline on standing, nor did it alter basal urinary catecholamine excretion. Submaximal work caused no significant change in plasma catecholamines before treatment, but there was a marked rise both in plasma noradrenaline and adrenaline during treatment with penbutolol. In short term studies there was a fall in plasma renin by 4 hours after oral administration of penbutolol 2-4 mg, which persisted for 24 hours. Prolonged treatment with penbutolol 20-30 mg twice daily inhibited renin production under basal conditions and following submaximal work, as well as lowered basal urinary aldosterone excretion. In one patient slight asthmatic symptoms appeared after treatment for 3 months with penbutolol. In other respects penbutolol was well tolerated.