Combined alpha- and beta-adrenoreceptors blockade with oral labetalol in hypertensive patients with reference to haemodynamic effects at rest and during exercise.

Twelve hypertensive patients received oral labetalol treatment (average final dose 1,200 mg/d) over a period of 16 months. 2 Satisfactory blood pressure control was maintained both at rest and after exercise. 3 Plasma renin activity was significantly reduced. 4 Postural hypotension measured in this group of patients after a single dose of labetalol 50 mg intravenously was considerably reduced during long-term oral treatment. 5 No serious side-effects were observed nor were there any significant changes in haematological and biochemical variables during the period. 6 Haemodynamic data obtained in two of the patients after 16 months' treatment suggests that the haemodynamic profile observed after acute intravenous administration is maintained after prolonged oral treatment.