Nitrates for heart attack and unstable angina

Examples

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Brand Name	Generic Name
Isordil	isosorbide dinitrate

Brand Name	Generic Name
ISMO	isosorbide mononitrate

Brand Name	Generic Name
Nitrostat	nitroglycerin

Nitrates are taken as a pill or a liquid sprayed under the tongue (sublingual). Skin patches or paste are also available. Nitrates may be injected into a vein in emergency situations, such as during a heart attack.

How to use nitroglycerin under the tongue

How It Works

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Nitrates open up (dilate) the arteries to the heart, increasing blood flow, relieving chest pain (angina), and reducing the heart's workload.

Why It Is Used

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Nitrates prevent and relieve angina. They may be used:

• During angina attacks.
• Before stressful activities that can cause angina (such as having sexual intercourse or walking up stairs or a hill).
• Over the long term to prevent angina that occurs during daily activities.
• In people who have had angioplasty or a stent placed, but who continue to have angina.

Spray and sublingual forms of nitroglycerin are available to relieve angina. Longer-acting pill or patch forms may be used for long-term prevention of chest pain during daily activities.

How Well It Works

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Nitrates have been shown to relieve chest pain, but they may only slightly reduce the risk of death in people having a heart attack.¹

Advantages and disadvantages of nitroglycerin

Advantages	Disadvantages
Works quickly Easy to administer when given intravenously or in pill form under the tongue (sublingual)	Effects wear off after 24 hours Often causes severe headaches

Side Effects

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Side effects of nitrates may include:

• A feeling of pulsating fullness in the head (most common side effect) or headache.
• A drop in blood pressure, which can cause dizziness.
• A burning sensation under the tongue (with nitroglycerin that is placed under the tongue).

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

What To Think About

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Different nitrate preparations are often combined. Pills, patches, or paste may be used together with sublingual nitroglycerin to give maximum relief and prevent angina.

Some people develop a tolerance to nitrates if they use them constantly over a long period. Tolerance occurs when a medicine loses its effectiveness and may not seem to work as well. A doctor may prescribe a daily schedule of using nitroglycerin 12 to 18 hours on and 6 to 12 hours off to prevent the development of tolerance.

Long-term nitroglycerin medicine is often added to other medicine (such as beta-blockers or calcium channel blockers) when a person is still having episodes of angina despite medicine use.

Regardless of whether your chest pain was relieved with nitroglycerin, you should let your doctor know that you had an episode of angina. If this is unusual for you or if your angina episodes are occurring more frequently or lasting longer, or if you need more medicine to control them, tell your doctor.

Nitroglycerin can get old. And when it is old, it may not work. If your nitroglycerin supply is past its expiration date, get a new prescription as soon as possible. Keep your nitroglycerin in the container it came in and tightly closed. Do not open your sublingual nitroglycerin until you need a dose. Replace your tablets every 3 to 6 months. A nitroglycerin spray may last up to 2 years before it expires.

You may get a headache when you use nitroglycerin. Or you may feel burning or tingling under your tongue with nitroglycerin that is used under the tongue. But if you don't have a headache or feel burning or tingling under your tongue, it does not mean the medicine is not working.

Do not take the erection-enhancing medicines sildenafil (Viagra), vardenafil (Levitra), or tadalafil (Cialis) if you are taking nitrates. Combining these two drugs can cause a life-threatening drop in blood pressure. If you develop chest pain and have taken one of these erection-enhancing medicines, be sure to tell your health professionals so that they do not attempt to treat you with nitroglycerin or another nitrate medicine.

Do not take the pulmonary hypertension medicine sildenafil (Revatio) if you are taking nitroglycerin or another nitrate medicine.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. Danchin N, Durand E (2006). Acute myocardial infarction, search date August 2004. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.

Credits

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Author	Robin Parks, MS
Editor	Kathleen M. Ariss, MS
Associate Editor	Pat Truman, MATC
Primary Medical Reviewer	Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer	Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
Last Updated	May 14, 2007