Vasodilators: Definition, Uses, Side Effects, and More
Wellness & SelfcareDrugs

What Are Vasodilators?

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Updated on January 31, 2025
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Vasodilators are a group of medicines used to treat, manage, or prevent many cardiovascular conditions, including high blood pressure and heart attacks.

Vasodilators open or widen blood vessels, which allows blood to flow more easily. This can help treat high blood pressure, improve blood flow, or prevent blockages in the veins, which are often the cause of cardiovascular events.

What Conditions Do Vasodilators Treat?

By dilating arteries and veins, vasodilators improve blood flow and help manage or prevent many conditions affecting the heart and cardiovascular system.

Vasodilators Condition List

Vasodilators are used to treat or prevent:

Vasodilators are also used in hypertensive emergencies that may occur in the following conditions:

  • Acute renal failure or acute kidney injury (a condition where the kidneys suddenly stop working well)
  • Acute pulmonary edema (when the lungs fill with fluid)
  • Aortic dissection (a tear in the inner layer of your aorta that can be life-threatening)

Types of Vasodilators

Different vasodilators are usually grouped into different types based on the way they work. You and your healthcare professional will decide together which vasodilator is right for your condition.

Below are some of the most common types of vasodilators.

Angiotensin-Converting Enzyme (ACE) Inhibitors

Common examples of ACE inhibitors include:

  • benazepril (Lotensin)
  • lisinopril ( Zestril)
  • enalapril (Vasotec)
  • captopril
  • fosinopril
  • moexipril
  • perindopril
  • quinapril
  • ramipril (Altace)
  • trandolapril

Angiotensin Receptor Blockers (ARBs)

Common examples of ARBs include:

  • azilsartan (Edarbi)
  • candesartan (Atacand)
  • irbesartan (Avapro)
  • losartan (Cozaar)
  • olmesartan (Benicar)
  • telmisartan (Micardis)
  • valsartan (Diovan)

Calcium Channel Blockers (CCBs)

Common examples of CCBs include:

  • amlodipine (Norvasc)
  • diltiazem (Cardizem, Tiazac, others)
  • felodipine
  • isradipine
  • nicardipine
  • nifedipine (Procardia)
  • nisoldipine (Sular)
  • verapamil (Verelan)

Direct-Acting Vasodilators

Examples of direct vasodilators include:

  • hydralazine (Apresoline)
  • minoxidil (Loniten)
  • nitroglycerin (Nitrostat)

How Do Vasodilators Work?

Vasodilators work by opening blood vessels or preventing them from being narrowed. How they do that depends on the type of vasodilator.

ACE inhibitors are a type of direct vasodilator because they work directly on the cells that line artery walls. They decrease enzymes that contribute to the process that narrows blood vessels. Reducing these enzymes prevents the narrowing of blood vessels and improves blood flow.

ARBs are a type of indirect vasodilator. They work by acting on chemicals involved in narrowing blood vessels. ARBs work by blocking angiotensin — a chemical that narrows the blood vessels — from attaching to the walls of your blood vessels.

CCBs are also an indirect vasodilator. They block calcium from reaching the walls inside your arteries. Among other chemicals, blood vessels also need calcium to narrow.

Other direct-acting vasodilators affect the smooth muscle cells inside your blood vessel walls directly, ‘telling’ them to relax. This quickly causes the blood vessels to widen.

What Are the Possible Side Effects of Vasodilators?

The side effects of vasodilators vary based on their type. However, overall, the side effects of vasodilators include:

  • Chest pain
  • Heart palpitations (fluttering or pounding heartbeat)
  • Rapid heartbeat (also called tachycardia)
  • Fluid retention
  • Nausea or vomiting
  • Dizziness
  • Headache
  • Flushing
  • Excessive hair growth
  • Joint pain
  • Dry cough
  • Inflammation of the pancreas (acute pancreatitis)
  • High potassium levels (hyperkalemia)
  • Low blood pressure (hypotension)
  • Constipation
Direct vasodilators like ACE inhibitors act quickly and cause more side effects. Indirect vasodilators cause fewer side effects but act more slowly.

Are There Any Risks Related to Vasodilators?

Vasodilators are powerful drugs. It’s important that you take them as prescribed, as misuse can have serious health consequences. CCBs, for example, are one of the main contributors to drug-related fatalities in the United States.

Tell your doctor about any other medical conditions you have before starting on a vasodilator. Some preexisting conditions could mean that vasodilators are not the right treatment for you or that only some vasodilators are safe.

For example, CCBs are not recommended if you’ve had severe hypotension, and nitrates may not be the right choice if you’ve had a heart attack in your right ventricle.

Vasodilators and Pregnancy

Tell your doctor if you're pregnant or might become pregnant while taking a vasodilator.

Some of these medicines — such as ACE inhibitors or ARBs — can cause unwanted effects and are therefore not indicated for pregnant people. Others, like CCBs or hydralazine, may be suited for treating conditions that occur during pregnancy, such as preeclampsia.

You and your healthcare professional will discuss the risks and benefits of taking certain vasodilators during pregnancy.

Diet, Lifestyle, and Other Precautions

  • Your doctor may suggest that you follow a special diet while taking vasodilators. Follow these instructions carefully.
  • Vasodilators can cause dizziness. Don't drive or perform activities that require alertness until you know how these medicines affect you.
  • Tell your healthcare provider that you're taking a vasodilator before having any type of medical procedure, including dental procedures.
  • Your doctor will want to perform frequent tests to monitor your body's response to these medicines. Keep all appointments with your doctor's office and laboratory.
Avoid excessive drinking, as alcohol may interfere with how vasodilators work in your body.

The Takeaway

  • Vasodilators are drugs that open or dilate your blood vessels. They’re used to manage or prevent many cardiovascular conditions, including high blood pressure.
  • There are many types of vasodilators, each with its own set of side effects and mechanism of action.
  • Vasodilators are potent drugs, so it’s important you discuss how suitable they are for you with your healthcare professional and take them as instructed.
  • Let your doctor know about all prescription, nonprescription, illegal, recreational, herbal, nutritional, or dietary drugs you're taking before starting on a vasodilator.
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Chung Yoon, MD

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Chung Yoon, MD, is a noninvasive cardiologist with a passion for diagnosis, prevention, intervention, and treatment of a wide range of heart and cardiovascular disorders. He enjoys clinical decision-making and providing patient care in both hospital and outpatient settings. He excels at analytical and decision-making skills and building connection and trust with patients and their families.
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