Penbutolol in hypertension, alone and in combination with furosemide. A long-term multicentre study.

Penbutolol is a new, potent and long-acting non-cardioselective beta-adrenergic blocker which has been evaluated in a 6-month open study of patients with moderate essential or renal hypertension. Eighty-two patients entered the study and 69 completed at least 3 months of treatment. Two-thirds of these showed a good response to penbutolol given alone as a single daily dose of either 40 mg or 80 mg. The major reduction in blood pressure occurred within the first 2 weeks of active therapy. This response was maintained for the entire study period. Blood pressure reduction after penbutolol did not correlate wtih the small reduction in heart rate observed. The remaining patients were treated with a combination of penbutolol and furosemide and most had achieved satisfactory control of their blood pressure by the end of the study. Penbutolol was well tolerated and produced no serious adverse effects. Some patients developed gastro-intestinal side-effects at the beginning of treatment which subsequently resolved. One patient with chronic glomerulonephritis showed a marked deterioration in renal function during the study. This may well have been related to disease progression. No other significant changes in biochemical or haematological parameters were observed.