Examples

Hydralazine

Nitrates

How It Works

Vasodilators work on different substances in the body to help widen (dilate) blood vessels. It is easier for the heart to pump blood if the blood vessels are widened.

Why It Is Used

Vasodilators are often combined with other medicines to treat heart failure. Hydralazine taken with a nitrate may be used as an alternative to angiotensin-converting enzyme (ACE) inhibitors if ACE inhibitors cannot be tolerated.

How Well It Works

For heart failure, hydralazine is typically used along with a nitrate. But nitrates may be used alone, without hydralazine, if you are taking it to relieve angina symptoms.

If you take hydralazine with a nitrate, you will also take other medicines for heart failure such as ACE inhibitors and beta-blockers. This combination of medicines may help relieve symptoms and lower the risk of early death. This benefit has been shown in African Americans but has not been shown in other groups of people.¹

Side Effects

The most common side effect is low blood pressure, which may cause symptoms of dizziness, weakness, or fainting. People who have low blood pressure when they start therapy will generally be started with a low dose and may need close monitoring to avoid reducing blood pressure too much.

Long-term use of these medicines is associated with fluid retention (with hydralazine) and loss of effectiveness (development of tolerance) with nitrates. For these reasons, their use may be limited.

Nitrates may cause headaches.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Vasodilator drugs seldom are used alone to treat heart failure.

If you are taking nitrates, do not use erection-enhancing medicines such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra). Do not take a nitrate and an erection-enhancing medicine together because you can have very low blood pressure, which can lead to death.

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References

Citations

1. Hunt SA, et al. (2009). 2009 focused update incorporated into the ACC/AHA 2005 guidelines for the diagnosis and management of heart failure in adults. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation, 119(14): e391–e479.