Haemodynamic effects of long-term oral labetalol.

1 The haemodynamic effects of labetalol have been studied in 11 hypertensive patients after 1 month of oral administration at a fixed dose of 800 mg/d. 2 Heart rate blood pressure and cardiac output were measured at rest and at two levels of exercise. 3 Labetalol significantly reduced heart rate and blood pressure at rest and after exercise but cardiac output remained unchanged. 4 The results suggest that labetalol is an effective anti-hypertensive agent acting by competitive adrenoreceptor blockade.