Medical Specialties: Cardiology, Family practice, Internal medicine

Clinical Definition

A vasodilator is a pharmacological agent that causes relaxation of the smooth muscle cells within the walls of the vessels. The relaxation results in dilation of the blood vessels. Vasodilators allow an increase in circulation and are used to treat conditions like hypertension.

In Our Own Words

Some types of medical conditions cause a narrowing of the vessels that carry blood throughout the body. A vasodilator is a class of drugs that dilates or opens up the blood vessels. Vasodilators are often used to treat high blood pressure.


Vasodilators relax the blood vessels and prevent them from tightening. As a result of the vessels being opened, blood flows easily through. Since blood is able to flow easily, the heart does not have to work as hard to pump blood throughout the body, and blood pressure is reduced.  

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  • University of North Carolina. UNC Invasive Cardiology Services. Vasodilator Challenges. Assessed September 2013.
  • Colbert, B., Mason, B., Gonzalez, L. “Integrated Cardiopulmonary Pharmacology (3rd Edition).” Prentice Hall 2011. Assessed September 2013.
  • Cleveland Clinic. Hydralazine-Nitrate Combination. Assessed September 2013.
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