The Right Way to Use Nitroglycerin Under Your Tongue

Nitroglycerin sublingual tablets work by dissolving under your tongue, where blood vessels absorb the medication directly into your bloodstream. You do not swallow them. Place one tablet under your tongue at the first sign of chest pain, sit or lie down, and let it dissolve completely — this usually takes 3 to 5 minutes. If the pain does not ease after 5 minutes, take a second dose. If pain continues 5 minutes after the second dose, call 911 when ready.

The medication reaches your heart faster this way than if you swallowed it, because the tissue under your tongue has many blood vessels and bypasses your digestive system. Speed matters when you are having chest pain. Keep your nitroglycerin tablets with you at all times, in their original brown or amber bottle — the bottle protects them from light and air, which break down the medication.

Key Takeaways

  • Place one tablet under your tongue at the first sign of chest pain and sit down when ready.
  • Let the tablet dissolve completely without chewing or swallowing it — this takes 3 to 5 minutes.
  • If pain does not ease after 5 minutes, take a second tablet and wait another 5 minutes.
  • Call 911 if chest pain continues 5 minutes after your second dose, or if the pain feels different from usual.
  • Store tablets in their original brown bottle away from heat and moisture, and check the expiration date monthly.

Step-by-Step Instructions for Taking a Dose

Stop what you are doing and sit down or lie down as soon as you feel chest pain. Remaining upright can lower your blood pressure too quickly and cause dizziness. Reach for your nitroglycerin bottle and remove one tablet.

Place the tablet under your tongue, in the pocket of tissue between your tongue and the floor of your mouth. Close your mouth and breathe normally. Do not chew the tablet, do not swallow it, and do not drink water. The tablet will begin to tingle or burn slightly as it dissolves — this is normal and means the medication is working. Most tablets dissolve in 3 to 5 minutes.

Sit or lie still while you wait. Your chest pain should begin to ease within a few minutes. If it does not, take a second tablet under your tongue and wait another 5 minutes. If the pain is still there after 10 minutes total (5 minutes for the first tablet, 5 minutes for the second), call 911 when ready. Do not drive yourself to the hospital.

When to Call 911 Instead of Taking a Tablet

Call 911 right away if your chest pain feels different from the pain you usually get, if it is more severe than usual, or if it lasts longer than 15 minutes even after taking two tablets. Call 911 if you have chest pain along with shortness of breath, nausea, sweating, or pain in your arm, jaw, or back. These can be signs of a heart attack, not just angina.

Do not wait to see if a tablet will work if something feels wrong. Emergency responders can begin treatment in the ambulance and have you at a hospital faster than you can drive. If you are unsure whether to call 911, call anyway — it is better to be cautious.

Storage and Shelf Life

Keep your nitroglycerin tablets in their original brown or amber bottle with the cap tightly closed. Light and air break down the medication, so do not transfer the tablets to a clear bottle or a pill organizer. Store the bottle at room temperature, away from heat, moisture, and direct sunlight. A bathroom medicine cabinet is not ideal because of humidity from showers — a bedroom drawer or kitchen cupboard away from the stove works better.

Check the expiration date on your bottle once a month. Nitroglycerin loses strength over time, especially if the bottle has been opened many times or stored in the wrong place. If your tablets have expired, ask your doctor or pharmacist for a new prescription. Do not use expired tablets during a chest pain emergency — they may not work.

Keep a fresh bottle with you when you travel. If you carry a purse or bag, keep one bottle there. If you exercise or spend time away from home, keep another bottle in a jacket pocket or gym bag. The goal is to have a tablet within reach whenever chest pain starts.

Side Effects and What to Expect

Nitroglycerin commonly causes a headache, especially the first few times you use it. This headache usually fades within 30 minutes. You may also feel a slight flushing or warmth in your face and neck, or a mild dizziness. These effects are normal and do not mean the medication is not working — in fact, they often mean it is.

If you feel very dizzy or faint after taking a tablet, lie down with your legs raised. This helps blood flow back to your heart and brain. If dizziness is severe or does not pass within a few minutes, call your doctor. Some people develop a tolerance to nitroglycerin if they use it too often — your doctor may recommend a schedule that includes a period each day when you do not use it, to keep the medication effective.

Interactions and Medications to Avoid

Do not take nitroglycerin if you have used certain medications for erectile dysfunction — sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra) — in the past 24 to 48 hours. The combination can cause a dangerous drop in blood pressure. Tell your doctor about all medications you take, including over-the-counter drugs and supplements, before you start using nitroglycerin.

Some blood pressure medications and pain relievers can interact with nitroglycerin. Your pharmacist can review your full medication list and let you know if there are any conflicts. If you start a new medication, mention to your doctor that you use nitroglycerin sublingual tablets.

When to Contact Your Doctor

Contact your doctor if you are using nitroglycerin more than once or twice a week, or if the pattern of your chest pain has changed. An increase in how often you need the medication can signal that your heart condition is worsening and your treatment plan may need to change. Do not straightforward use more tablets — call your doctor instead.

Also contact your doctor if you develop a persistent headache after using nitroglycerin, if you feel faint or very dizzy, or if the tablets no longer seem to relieve your chest pain. Your doctor may adjust your dose, switch you to a different form of the medication, or add another heart medication to your routine.

Frequently Asked Questions

Can I chew or swallow nitroglycerin tablets?

No. Chewing or swallowing nitroglycerin tablets slows how fast the medication reaches your bloodstream and makes it less effective during a chest pain emergency. The sublingual route — under the tongue — is the only correct way to use these tablets. If you have trouble letting a tablet dissolve without swallowing, talk to your doctor about other forms of nitroglycerin.

What should I do if I accidentally swallow a tablet?

Do not take another tablet right away. The medication will still work, just more slowly. If your chest pain does not ease within 10 minutes, take a second tablet under your tongue as directed. If you swallow tablets regularly by accident, tell your doctor — there may be a better form of the medication for you.

How long does nitroglycerin take to work?

Most people feel relief from chest pain within 3 to 5 minutes of placing a tablet under their tongue. If pain does not ease by the 5-minute mark, take a second tablet. If pain continues 5 minutes after the second dose, call 911.

Can I use an old bottle of nitroglycerin tablets?

No. Check the expiration date before every use. Nitroglycerin loses potency over time and may not work when you need it. If your tablets have expired, get a new prescription from your doctor or pharmacist right away.

What if I feel dizzy after taking nitroglycerin?

Lie down when ready with your legs raised higher than your heart. This helps blood flow back to your brain. Dizziness usually passes within a few minutes. If it is severe or does not improve, call your doctor. Dizziness can mean your blood pressure dropped too much, and your doctor may need to adjust your dose.