Nitrates for heart attack and unstable angina

Examples

Generic Name	Brand Name
isosorbide dinitrate	Cedocard
isosorbide mononitrate	Imdur
nitroglycerin	Nitro-Dur, Nitrolingual, Nitrostat, Transderm-Nitro

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

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

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

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

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

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.

If nitroglycerin is old, the tablets may not work well. Get a new prescription as soon as possible if your supply is past the expiration date. Usually you should replace your tablets every 3 to 6 months. A nitroglycerin spray may last up to 2 years before it expires.

There are ways to tell whether your nitroglycerin is still effective. You should have a headache when you use it. Or if you use nitroglycerin under your tongue, you should feel a slight tingle or burn when you place it there. If you do not notice these signs, your nitroglycerin is probably old. In this case, contact your health professional to get a new prescription. Fill the prescription as soon as possible, and discard your out-of-date nitroglycerin.

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.

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Author:	Douglas Dana Robin Parks, MS	Last Updated: August 15, 2007
Medical Review:	Anne C. Poinier, MD - Internal Medicine Caroline S. Rhoads, MD - Internal Medicine Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
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