Generic name: Glyceryl trinitrate.

Other brand names: Ang-O-Span, Deponit, Klavikordal, N-G-C, Niong, Nitro-Bid, Nitro-Dur, Nitroglyn, Nitroguard, Nitrolingual Spray, Nitronet, Nitrong, Nitrostat Tablets, NTS, Transaerm-Nitro.

Nitroglycerin is an anti-anginal agent, or vasodilator. It increases the amount of oxygen that reaches the heart muscle. 

Quick Facts About Nitroglycerin


Used to prevent and treat angina pectoris (crushing chest pain).

Nitroglycerin Dosage

Follow doctor’s instructions carefully for the brand prescribed; never interchange brands. If used excessively, at risk for acute headaches or tolerance. However, daily headaches indicate the drug’s activity; do not reduce dosage unless instructed by your doctor. Do not open sublingual tablet container until you need a dose. Do not put cotton plug or objects into container. Keep sublingual tablets accessible at all times.

  • Usual adult dose: sublingual or buccal tablets — at onset of chest pain, dissolve 1 tablet under tongue or inside cheek. May repeat every 5 minutes until pain subsides. If pain does not subside after 15 minutes or 3 tablets, immediately contact your doctor. May take tablets 5 to 10 minutes prior to activities that may cause chest pain. Patch — applied to skin for 12 to 14 hours, off for 10 to 12 hours, then new patch applied, per doctor’s instructions. Spray — at onset of chest pain, spray 1 or 2 premeasured doses onto or under tongue. If pain does not subside after 15 minutes or 3 doses, immediately contact your doctor. May use spray 5 to 10 minutes prior to activities that may cause chest pain. Ointment — total of 1 inch of ointment per day, 1/2 inch in the morning and 1/2 inch 6 hours later. Chest is the site with highest absorption. Must have 10-to-12-hour period with no ointment on skin. Sustained-release capsules or tablets — doctor will prescribe smallest amount to take 2 or 3 times per day at 8-to-12-hour intervals. Seniors — lower doses are prescribed.
  • Usual child dose: not generally prescribed for children.
  • Missed dose: skin patch or ointment — apply as soon as possible, unless almost time for next dose. If so, skip missed dose, go back to regular schedule. Do not apply 2 skin patches at the same time. Oral tablets or capsules — take as soon as possible, unless within 2 hours of next dose. If so, skip missed dose; go back to regular schedule. Do not double doses.

Nitroglycerin Side Effects

Overdose symptoms:

bluish skin, clammy skin, colic, coma, confusion, diarrhea (possibly bloody), difficulty and/or slow breathing, dizziness, feinting, fever, flushed skin, headache (persistent and throbbing), increased pressure within skull, irregular pulse, loss of appetite, nausea, palpitations, paralysis, rapid decrease in blood pressure, seizures, slow pulse/heartbeat, sweating, vertigo, visual disturbances, vomiting. If you suspect an overdose, immediately seek medical attention.

Severe overdose can result in death.

More common side effects: dizziness, flushed neck and fece, headache, light-headedness, worsened angina.

Less common or rare Nitroglycerin side effects: diarrhea, feinting, heart pounding, low blood pressure, nausea, numbness, pallor, restlessness, skin rashes, sweating, vertigo, vomiting, weakness.


Inform your doctor before combining Nitroglycerin with:

blood vessel dilators such as Loniten; calcium channel blockers such as Calan and Procardia; Dihydroergotamine (D.H.E.); high blood pressure medications (may cause extremely low blood pressure); isorbide mononitrate (Ismo); isosorbide dinitrate (Sorbitrate or Isordil); Tenormin.

Avoid alcohol; may cause sudden drop in blood pressure resulting in dizziness and fainting.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Not known if nitroglycerin appears in breast milk.

To avoid low blood pressure and headaches, lower doses are prescribed for seniors.

Not generally prescribed for children.

  • May cause drowsiness and impair your ability to drive a car or operate machinery. Do not take part in any activity that requires alertness.
  • Should not use if you have: head injury or condition causing increased fluid pressure in the head; severe anemia; recent heart attack; kidney, liver, or thyroid disease. Avoid using capsule form if you have dosed-angle glaucoma or suffer from dizziness when standing.
  • Immediately stop taking this medication and inform your doctor if you experience blurred vision or dry mouth.
  • Use with caution if you have low systolic blood pressure (less than 90 mm Hg).
  • Nitroglycerin increases risk of severe low blood pressure, slowed heart rate, and increased chest pain.
  • Should not use if sensitive to or allergic to nitroglycerin or adhesive used in the patch.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Nitroglycerin side effects, please contact your healthcare provider