Hydralazine

Abstract

Hydralazine (1-hydrazinophthalazine) (Fig. 1) has been used in the therapy of hypertension for 25 years. In combination with other drugs it is very useful for treating chronically hypertensive patients. The role of hydralazine in antihypertensive therapy has expanded during recent years since it was demonstrated that the drug is particularly effective when combined with propranolol or other beta-adrenergic antagonists.^{1 2 3 4 5 6} Closely related phthalazine derivatives, particularly 1,4-dihydrazinophthalazine, are employed outside the United States, but they offer no apparent advantage over hydralazine.Mechanism of ActionHydralazine exerts its hypotensive action by reducing vascular resistance through direct relaxation of arteriolar smooth muscle.^{7 8 9 10 11} The cellular . . .