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Glyceryl trinitrate rectal ointment


Glyceryl trinitrate rectal ointment can ease the pain associated with small tears of skin around the back passage (anal fissures).

Use the ointment twice daily at 12-hourly intervals. You can use it for up to eight weeks if necessary.

The most common side-effect is a headache.

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About glyceryl trinitrate rectal ointment

Type of medicine

A nitrate

Used for

Pain relief for anal fissures (in adults)

Also called

Nitroglycerin (in US); Rectogesic®

Available as

Rectal ointment

An anal fissure is a small tear of the skin around your back passage (anus). Glyceryl trinitrate (GTN) rectal ointment (Rectogesic®) works by relaxing the muscle just inside your back passage. Relaxing this muscle increases the flow of blood to the area, which eases pain. It can be helpful where other treatments have not been effective.

A different brand of glyceryl trinitrate ointment (Percutol®) is used to relieve angina pain. For information on this product please see our medicine leaflet Glyceryl trinitrate for angina.

Before using glyceryl trinitrate rectal ointment

To make sure that this is the right treatment for you, before you start using GTN rectal ointment it is important that your doctor knows:

  • If you are pregnant or breastfeeding.

  • If you have any problems with the way your liver works, or any problems with the way your kidneys work.

  • If you have migraines or severe headaches.

  • If you have low blood pressure, or a heart condition.

  • If you have been told by a doctor you have low levels of iron in your blood (anaemia), or low levels of oxygen in your blood (hypoxaemia).

  • If you have an underactive thyroid gland.

  • If you have an eye condition called glaucoma.

  • If you have recently had a head injury or a heart attack.

  • If you have ever had an allergic reaction to a medicine.

  • If you are taking other medicines, including those available to buy without a prescription, as well as herbal or complementary medicines. It is particularly important that you tell your doctor if you are using any medicines to help treat erectile dysfunction.

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How to use glyceryl trinitrate rectal ointment

  • Before you use the ointment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about using the ointment, and it will also provide you with a full list of side-effects which you could experience.

  • Cover your finger with a finger cot (available from pharmacies), or a piece of cling film, or use a disposable glove. Then measure out 2.5 cm of the ointment from the tube on to your finger (there is a measuring line on the packaging to help you). Then, using your finger, gently insert the ointment just inside your back passage. To make sure that the ointment gets to the correct place, insert your finger to the first finger joint. Apply the ointment this way every 12 hours until the pain goes away. You can continue to use the ointment for up to eight weeks, if needed.

Getting the most from your treatment

  • Remember to follow any lifestyle or dietary advice you have been given by your doctor. Try to avoid becoming constipated, by eating a high-fibre diet and drinking several glasses of water each day.

  • It is best not to drink alcohol while you are using GTN rectal ointment. Alcohol will increase the chance that you experience side-effects such as feeling dizzy and light-headed.

  • If you experience any bleeding from your back passage, or if your symptoms do not improve, you should discuss this with your doctor.

  • If you buy any medicines, check with a pharmacist that they are suitable for you to take while you are using GTN rectal ointment.

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Can glyceryl trinitrate rectal ointment cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with GTN rectal ointment. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Very common glyceryl trinitrate rectal ointment side-effects (these affect more than 1 in 10 people)

What can I do if I experience this?


Ask your pharmacist to recommend a suitable painkiller. If the headache is severe or if it continues, please ask your doctor for further advice

Common glyceryl trinitrate rectal ointment side-effects (these affect fewer than 1 in 10 people)

What can I do if I experience this?

Feeling light-headed or dizzy

Do not drive and do not use tools or machines while affected

Feeling sick (nausea)

Try to stick to simple meals (avoid rich or spicy foods). If it becomes troublesome, please speak with your doctor

Less common glyceryl trinitrate rectal ointment side-effects

What can I do if I experience this?

Blurred vision, diarrhoea, local burning or itching

If any become troublesome, please speak with your doctor

If you experience any other symptoms which you think may be due to the ointment, please speak with your doctor or pharmacist for further advice.

How to store glyceryl trinitrate rectal ointment

  • Once opened, do not store or use the ointment for longer than eight weeks.

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

Never use more than the prescribed dose. If you suspect that someone might have swallowed some of the ointment by accident, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or dental treatment, please remember to tell the person carrying out the treatment which medicines you are taking/using.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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