Chronic anal fissure: 0.2% topical glyceryl trinitrate ointment

About topical glyceryl trinitrate

A topical 0.4% gylceryl trinitrate ointment (also called Rectogesic 4 mg/g Rectal Ointment) is licensed in the UK to treat chronic anal fissure in adults, but not children or young people. Glyceryl trinitrate is commonly abbreviated to GTN and is also sometimes call nitroglycerin. The 0.4% figure gives an indication of the strength of the medicine because it tells us the amount of active ingredient present in the ointment (in this case, the amount of glyceryl trinitrate).

A small amount of the ointment is applied to the affected area twice a day and is used to relieve pain caused by the fissure. The glyceryl trinitrate helps the ring muscle (sphincter) that goes around the anus (back passage) to relax which allows more blood to flow to the lining of the anus (back passage). This may aid the healing process and may relieve the pain.

Treatment with glyceryl trinitrate often causes headache and about 20 in every 100 people using the 0.4% ointment have very bad headaches. These can sometimes be treated successfully with painkillers such as paracetamol but the headache causes some people to stop using the medicine. Some healthcare professionals consider prescribing a 0.2% strength of glyceryl trinitrate ointment (the 0.2% ointment is half as strong as the 0.4% ointment) in the hope it may reduce the number or severity of headaches associated with the 0.4% strength, but still provide pain relief or help heal the fissure. The 0.2% glyceryl trinitrate ointment is not licensed in the UK to treat any medical condition in any age group and is known as an 'unlicensed' medicine.

The 0.2% strength of the ointment is also sometimes used in children and young people because there are no licensed medicines available for treating chronic anal fissure in this age group.