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Glyceryl trinitrate (tablet)

glis-er-ril try-nye-trate

What does it do?

Glyceryl trinitrate is used to relieve angina. It relaxes the blood vessels, allowing more blood to flow to the heart.

How should you take it?

Glyceryl trinitrate tablets should be placed under the tongue and allowed to dissolve. Do not crush, chew or swallow glyceryl trinitrate tablets.

Stop what you are doing. Sit down and place 1 tablet under your tongue.
If your angina is relieved by rest or your tablet, you can resume your activities gently.
If after 5 minutes you still have angina, place 1 more tablet under your tongue.
If you still have angina after 5 more minutes, treat as a heart attack – call an ambulance (dial 111) immediately.

Can you take other medicines?

Some medicines available without a prescription may react with glyceryl trinitrate including:

  • sildenafil (e.g. Viagra®) or similar medicines. Taking these and glyceryl trinitrate together may cause severe side effects - discuss this with your health professional.

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Flushing, headache

Fast heartbeat

Fainting, lightheaded

Lie down until these effects pass – tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Tell your doctor if you have a history of fainting, or sometimes feel lightheaded.
  • Taking alcohol and glyceryl trinitrate at the same time may increase side-effects.
  • The tablets can be used for up to 3 months after the bottle is first opened. After this time they may not work, so you will need to get a new supply. Always keep the tablets in their original bottle with the lid firmly closed.
  • You may feel a slight tingling in your mouth when you use glyceryl trinitrate. This is harmless.
  • You may use glyceryl trinitrate before an activity that sometimes causes your angina. Discuss this with your doctor.
  • Keep your glyceryl trinitrate handy at all times, so you know where it is when you need it.
  • If you feel lightheaded or faint after using your glyceryl trinitrate, do not drive or operate machinery until this feeling goes away.

This leaflet contains important, but not all, information about this medicine.

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. December 2017

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at the Canterbury District Health Board. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed