Glyceryl trinitrate, or GTN, is a type of medicine called a nitrate. It's used to prevent and treat chest pain caused by angina.
It can help stop chest pain if an angina attack has already started. It can also help to prevent the chest pain starting.
It comes as tablets or as a spray that you put under your tongue. It also comes as patches that you put on your skin.
Sometimes GTN patches are used in hospital to make your veins easier to see if you need to have a drip (infusion).
GTN is also available as a rectal ointment used to treat tears in the skin around your bottom (anal fissures).
GTN rectal ointment is available on prescription. You can buy GTN tablets, spray and patches from a pharmacy.
Key facts
- You use GTN skin patches every day to help prevent chest pain caused by angina from starting. You use the tablets or spray during an angina attack, or before any activity that's likely to cause an attack.
- The most common side effects include headaches, feeling dizzy or facial flushing.
- If GTN makes you feel dizzy, sleepy or faint, do not drive, ride a bike or use tools or machinery until you feel better.
- It's best not to drink too much alcohol while taking GTN as this can make you feel dizzy, sleepy or faint.
- If you're having surgery, let the doctors know that you use GTN. They might ask you to stop using it before surgery.