Vasodilators are medicines that act directly on muscles in blood vessel walls to make blood vessels widen (dilate).

Vasodilators are used to treat high blood pressure (hypertension). By widening the arteries, these drugs allow blood to flow through more easily, reducing blood pressure. Controlling high blood pressure is important because the condition puts a burden on the heart and the arteries, which can lead to permanent damage over time. If untreated, high blood pressure increases the risk of heart attacks, heart failure, stroke, or kidney failure. Vasodilators usually are prescribed with other types of blood pressure drugs and rarely are used alone.

Examples of vasodilators are hydralazine (Apresoline) and minoxidil (Loniten). The vasodilator hydralazine also may be used to control high blood pressure in pregnant women or to bring down extremely high blood pressure in emergency situations. In the forms used for treating high blood pressure (tablets or...