Health Library Using Nitroglycerin for Sudden Chest PainFrom Healthwise

What is nitroglycerin?

Nitroglycerin is a vasodilator, a medicine that opens blood vessels to improve blood flow. It is used to treat angina—a type of chest pain—that happens when there is not enough blood flowing to the heart. To improve blood flow to the heart, nitroglycerin opens up (dilates) the arteries in the heart ( coronary arteries), which improves symptoms and reduces how hard the heart has to work.

Nitroglycerin comes in a quick-acting tablet or spray form, or as a long-acting pill. The quick-acting pill or spray forms are used under the tongue (sublingually). Your health professional will prescribe the right amount for you. Do not use another person's nitroglycerin.

When do I use nitroglycerin under the tongue?

Your health professional will advise you when to use your nitroglycerin. Generally, nitroglycerin under the tongue is used:

• To relieve sudden angina.
• Before stressful activities that can cause angina, such as walking uphill or having sexual intercourse.

How do I use nitroglycerin under the tongue?

• Sit or lie down to take your nitroglycerin. If you are driving, pull over and park the car. Taking nitroglycerin can lower your blood pressure, which could cause you to pass out if you are standing up.
• For sudden episodes of angina, use nitroglycerin in a tablet or liquid spray form.
  • The tablet should be placed under your tongue and left until it dissolves. If you accidentally swallow the tablet, take another. The medicine won't work if it is swallowed.
  • To use the spray, lift your tongue and depress the spray canister button once.
• Take one tablet or spray dose. If after 5 minutes the chest pain is not better or gets worse, call 911 or other emergency services immediately.
• After calling 911 , continue to stay on the phone with the emergency operator—he or she will give you further instructions.
• Regardless of what happens, you should let your health professional know that you had an episode of angina. If this is unusual for you, your angina episodes are occurring more frequently or lasting longer, or you need more medicine to control them, tell your health professional. Report any change in your chest pain (unstable angina) to your health professional.

A fresh tablet should taste bitter and sting when you put it under your tongue. If it does not, it probably is not effective and you should take another.

Are there side effects or interactions with other drugs I should be aware of?

Normal, temporary side effects of nitroglycerin include a warm or flushed feeling, headache, dizziness, or lightheadedness. You may also feel a burning sensation under your tongue.

Do not take the erection-enhancing medicine sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis) if you are taking nitroglycerin. Combining nitroglycerin with any of these medicines 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 professional so that you are not given nitroglycerin or another nitrate medicine.

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

How should I store nitroglycerin?

Store nitroglycerin pills in a dark-colored (such as brown), airtight, glass container that you cannot see through. Keep nitroglycerin pills and liquid spray away from heat or moisture.

Can nitroglycerin get old and lose potency?

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.

• Coronary Artery Disease
• Heart Attack and Unstable Angina

Author:	Robin Parks, MS	Last Updated: April 23, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
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