Rectogesic rectal ointment

Rectogesic rectal ointment contains the active ingredient glyceryl trinitrate, which is a type of medicine called a nitrate. It is used to relieve pain associated with anal fissures.
An anal fissure is a tear in the lining of the back passage (anus). It is often caused by passing hard stools when you are constipated. The tear is painful and often bleeds when you pass a stool.
The tear may also be caused in part by spasm (tightening) of the muscle around the anus (the internal sphincter). Spasm of this muscle also causes pain, because if the muscle around the anus is tight, the blood supply to the anus is reduced.