Nitrates are a vasodilator. Vasodilators widen (dilate) the blood vessels, improving blood flow and allowing more oxygen-rich blood to reach the heart muscle.

Why do I need to take nitrates?

Nitrates are used to treat the chest pain associated with angina and to ease the symptoms of congestive heart failure (CHF).

How do nitrates work?

Nitrates are a vasodilator. Vasodilators widen (dilate) the blood vessels, improving blood flow and allowing more oxygen-rich blood to reach the heart muscle. Nitrates also relax the veins to ease the workload on the heart when blood is returning to the heart from the arms and legs.

How much do I take?

Nitrates come in different forms. Depending on the form you are taking, nitrates can be used to prevent an angina attack, limit the number of attacks that you have, or relieve the pain of a current attack.

  • Pill forms include oral (swallowed with liquid), chewable (chewed and held in the mouth before swallowing), sublingual (dissolved under the tongue), or buccal (held under the lip or in the cheek until they dissolve).
  • The topical (ointment) or transdermal (stick-on patch) forms send nitrates through the skin.
  • The translingual (spray) form is sprayed on or under the tongue.

The amount of medicine that you need to take may vary. Talk to your doctor or pharmacist for more information about how and when to take this medicine.

What if I am taking other medicines?

Other medicines that you may be taking can increase or decrease the effect of nitrates. These effects are called an interaction. Be sure to tell your doctor about every medicine and vitamin or herbal supplement that you are taking, so he or she can make you aware of any interactions.

The following are categories of medicines that can increase or decrease the effects of nitrates. Because there are so many kinds of medicines within each category, not every type of medicine is listed by name. Tell your doctor about every medicine that you are taking, even if it is not listed below.

  • Viagra (sildenafil), Levitra (vardenafil), or Cialis (tadalafil). Do not take Viagra, Levitra, or Cialis within 24 hours of taking nitrates. When these erectile dysfunction medicines are mixed with nitrates, the combination can lower your blood pressure and make you dizzy, lightheaded, or faint. In some cases, patients have died after mixing erectile dysfunction medicines with nitrates.
  • Medicines to treat high blood pressure
  • Certain heart medicines
  • Over-the-counter cough, cold, and flu medicines
  • Over-the-counter herbal supplements for treating cough, cold, and flu

While taking nitrates, you should avoid smoking. Smoking can decrease the effect of the medicine. You should also avoid alcohol, because it can increase the effect of the medicine.

What else should I tell my doctor?

Talk to your doctor about your medical history before you start taking nitrates. The risks of taking the medicine need to be weighed against the good it will do. Here are some things to consider if you and your doctor are deciding whether you should take a nitrate.

  • You are thinking of becoming pregnant, you are pregnant, or you are breast-feeding your baby.
  • You are over 60. Dizziness is more common in older patients.
  • You have recently had a stroke.
  • You have recently had a heart attack.
  • You have kidney or liver disease.
  • You have an overactive thyroid.
  • You often have severe headaches.
  • You have anemia.
  • You have glaucoma.

What are the side effects?

Sometimes a medicine causes unwanted effects. These are called side effects. Not all of the side effects for nitrates are listed here. If you feel these or any other effects, you should check with your doctor.

Common side effects:

  • Dizziness
  • Headaches
  • Flushing of your face and neck
  • Upset stomach or throwing up
  • Low blood pressure (hypotension)
  • Irregular heart rhythms (arrhythmia)

Less common side effects:

  • Fainting
  • Restlessness

Rare side effects:

  • Dry mouth
  • Skin rash and peeling
  • Blurry vision

Again, tell your doctor right away if you have any of these side effects. Do not stop taking your medicine unless your doctor tells you to. If you stop taking your medicine without checking with your doctor, it can make your condition worse.



The information in this Medicines for Cardiovascular Disease section has been taken from a number of sources. It is meant to give you information about certain medicines, but it does not cover all of the possible uses, warnings, side effects, or interactions with other medicines and vitamin or herbal supplements. This information should not be used as medical advice for individual problems. Please talk to your doctor and/or your pharmacist for prescription instructions.
A consumer-based site by the American Society of Health-System Pharmacists that provides information about all types of medicines as well as safety tips for their proper use. The site’s search feature lets users search medicines by the brand or generic name.