Nitroglycerin is used to prevent attacks of chest pain (angina).

Nitroglycerin may also be used for purposes not listed in this medication guide.

You should not use this medicine if you are also using medicine to treat pulmonary arterial hypertension or erectile dysfunction.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Nitroglycerin topical is usually applied 2 times daily. Follow your doctor's instructions carefully.

Wash your hands after applying nitroglycerin.

Do not take by mouth. Topical medicine is for use only on the skin.

Nitroglycerin topical will not work fast enough to treat an angina attack that has already begun. Your doctor may prescribe an oral form of nitroglycerin (tablet, capsule, spray) to treat an angina attack. Talk with your doctor if any of your medicines do not seem to work as well in treating or preventing angina attacks.

If you need to have any type of surgery or dental work, tell the surgeon or dentist ahead of time that you are using nitroglycerin topical.

Store this medicine at room temperature, away from moisture and heat.

You should not use nitroglycerin if you are allergic to it.

Do not take erectile dysfunction medicine (Viagra, Cialis, Levitra, Stendra, Staxyn, sildenafil, avanafil, tadalafil, vardenafil) while you are using nitroglycerin topical. Using erectile dysfunction medicine with nitroglycerin can cause a sudden and serious decrease in blood pressure.

Tell your doctor if you have ever had:

• a heart attack or other heart problems;

• a stroke or head injury; or

• low blood pressure.

Tell your doctor if you are pregnant or breastfeeding.

Apply the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not apply two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of nitroglycerin can be fatal.

Overdose symptoms may include a severe throbbing headache, confusion, fever, fast or pounding heartbeats, dizziness, vision problems, vomiting, bloody diarrhea, trouble breathing, cold or clammy skin, fainting, and seizures.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Drinking alcohol can increase certain side effects such as dizziness, drowsiness, feeling light-headed, or fainting.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Nitroglycerin may cause serious side effects. Call your doctor at once if you have:

• pounding heartbeats or fluttering in your chest;

• slow heart rate;

• a light-headed feeling, like you might pass out; or

• heart attack symptoms--chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating.

Nitroglycerin can cause severe headaches. These headaches may gradually become less severe as you continue to use nitroglycerin. Do not stop taking nitroglycerin. Ask your doctor before using any headache pain medication.

Common side effects of nitroglycerin may include:

• flushing (warmth, redness, or tingly feeling);

• headache; or

• dizziness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your current medicines, especially:

• aspirin, heparin;

• medicine used to treat blood clots;

• blood pressure medication; or

• ergot medicine--dihydroergotamine, ergotamine, ergonovine, methylergonovine.

This list is not complete and many other drugs may affect nitroglycerin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.