What effect do vasodilators have on blood pressure?

Vasodilators are medications or substances that cause the dilation, or widening, of blood vessels. This dilation leads to a reduction in vascular resistance, which subsequently decreases blood pressure. By relaxing the smooth muscles in the walls of the blood vessels, vasodilators allow blood to flow more freely and reduce the overall pressure exerted on the vessel walls.

The primary therapeutic goal of vasodilators is often to lower blood pressure in conditions such as hypertension or heart failure, where reducing the afterload on the heart can improve cardiac output and decrease symptoms. Therefore, the fundamental effect of vasodilators is to decrease blood pressure, making this the correct answer. While there are various functions that other substances or interventions may have on blood pressure and cardiovascular function, the specific role of vasodilators firmly aligns with a decrease in blood pressure.