Glyceryl trinitrate is an effective treatment for anal fissure

It has been suggested that chronic anal fissure is ischemic in origin because of poor blood supply and spasm of the internal anal sphincter. Nitric oxide donors such as glyceryl trinitrate (GTN) cause a chemical sphincterotomy leading to healing of the fissure. This study addresses the hypothesis that topical GTN ointment may be an effective nonsurgical treatment for chronic anal fissure.

Thirty-nine consecutive patients (23 women; median age, 34 (range, 16-54) years) with chronic anal fissure presenting to the surgical outpatient department were treated for four to six weeks with 0.2 percent GTN ointment applied twice daily to the anoderm. Maximum anal resting pressure was measured at steady state before and after application of the ointment at the first visit. Patients were assessed at two weekly intervals.

Previous surgery for fissure had been performed in seven patients. There were 30 posterior and 9 anterior fissures. Resting maximum anal resting pressure fell from 122.1 +/- 44 to 72.5 +/- 33.3 cm of water (mean +/- standard deviation) by 20 minutes after application of ointment (P < 0.0001; paired t-test). Healing was complete in 14 patients at four weeks and in 33 patients at six weeks. Fissures recurred in five patients after treatment had been stopped. Four recurrences were successfully treated by further GTN ointment and one by sphincterotomy.

This study shows that most anal fissures can be treated nonsurgically with topically applied 0.2 percent GTN ointment. Prospective, randomized controlled trials are now needed, because nonsurgical treatment of anal fissure avoids permanent division of part of the sphincter and the consequent disturbance of continence mechanisms.