Comparison of labetalol and dihydralazine in hypertensive emergencies of pregnancy.

Labetalol (Trandate; Allen & Hanburys), a combined alpha- and beta-adrenergic blocking agent, was compared with the more commonly used peripheral vasodilator, dihydrallazine (Nepresol; Ciba), each administered as an infusion, in the treatment of severe hypertension in 20 primigravidas at greater than or equal to 32 weeks' gestation. With the dosage regimen used in this study there was a tendency towards more effective blood pressure control with dihydrallazine. The pulse rate was unaffected by labetalol therapy and there were no harmful effects on the neonate or fetus directly attributable to either drug.