Nitroglycerin is used in adults to treat or prevent attacks of chest pain (angina).

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

Get emergency medical help if you still have chest pain after using a total of 3 doses in 15 minutes, or if you have chest pain that seems unusual.

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

You may use nitroglycerin sublingual within 5 to 10 minutes before an activity that might cause chest pain.

Use nitroglycerin sublingual at the first sign of chest pain. Use another dose every 5 minutes as needed, up to a total of 3 doses within a 15-minute period.

Sublingual spray:

• Before your first use, prime with 5 to 10 sprays into the air, away from your face. Prime again if has not been used within 6 weeks with one to two sprays, or if it has not been used within 3 months with up to 5 sprays.

• Spray one or two sprays on or under the tongue and avoid swallowing. Do not rinse your mouth or spit out nitroglycerin for 5 to 10 minutes after use. The spray should not be inhaled.

Sublingual tablet: Place one tablet under the tongue and allow it to dissolve without swallowing. Do not swallow, chew, or suck the sublingual tablet.

Sublingual powder: Empty one or two packet contents under your tongue, allowing the powder to dissolve without swallowing. Do not rinse your mouth or spit for 5 minutes after use.

Capsule: Take by mouth as directed by your doctor, usually 3 to 4 times a day. Do not take the capsule to treat sudden chest pain.

Get emergency medical help if you still have chest pain after using a total of 3 doses in 15 minutes, or if your chest pain seems unusual.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using nitroglycerin.

Your condition may get worse if you stop using nitroglycerin suddenly. Ask your doctor before stopping the medicine.

Store this medicine in the original container at room temperature away from moisture and heat.

Keep the spray away from open flame or high heat. Do not puncture or burn an empty canister.

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

You may not be able to use nitroglycerin if you have:

• severe anemia (very low red blood cells);

• increased pressure inside the skull;

• blood circulation problems or if your heart cannot pump blood properly; or

• if you also take riociguat, vericiguat, or medicines such as avanafil (Strendra), sildenafil (Revatio, Viagra), tadalafil (Adcirca, Cialis) o vardenafil (Levitra, Staxyn).

Tell your doctor if you have or have ever had:

• a heart attack or other heart problems; or

• low blood pressure.

Tell your doctor if you are pregnant or breastfeeding.

Nitroglycerin is used when needed. If you are on a dosing schedule, skip any missed dose. Do not use two doses at one time.

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

Overdose symptoms may include a throbbing headache, confusion, pounding heartbeats, vision problems, vomiting, bloody diarrhea, sweating, clammy skin, blue lips, weak or shallow breathing, loss of movement, seizure, or fainting.

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

Drinking alcohol with nitroglycerin can cause side effects.

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:

• severe or throbbing headaches that do not become less severe with continued use of nitroglycerin;

• pounding heartbeats or fluttering in your chest;

• slow heart rate;

• feeling like you might pass out; or

• new or worsening chest pain.

Common side effects of nitroglycerin may include:

• headache, dizziness; or

• numbness, tingling, burning pain.

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 other medicines, especially:

• heart or blood pressure medication; or

• migraine headache medicine such as dihydroergotamine, ergotamine, ergonovine, methylergonovine.

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