Botulinum might be more effective than nitroglycerine in anal fissure


Clinical Question:
Is type A botulinum toxin more effective than nitroglycerine ointment in treating chronic anal fissure?

Bottom Line:
In this study, botulinum toxin (Botox, Dysport) appeared slightly more effective than topical nitroglycerine in managing chronic anal fissures. (LOE = 2b)

Brisinda G, Cadeddu F, Brandara F, Marniga G, Maria G. Randomized clinical trial comparing botulinum toxin injections with 0.2 per cent nitroglycerin ointment for chronic anal fissure. Br J Surg 2007;94:162-167.  [PMID:17256809]

Study Design:
Randomized controlled trial (single-blinded)

Unknown/not stated


Outpatient (specialty)

These authors randomly assigned 100 patients with anal fissure of at least 2 months duration to receive type A botulinum (30 units Botox or 90 units Dysport; administered as 2 injections of equal volume, one on each side of the anterior midline of the internal anal sphincter) or topical nitroglycerine (2 grams of 2% nitroglycerine diluted in 100 grams of soft paraffin) applied to the anus and anal canal 3 times daily for 8 weeks. The patients, who were aware of the treatment administered, were evaluated every month by physicians unaware of the treatment. Patients who had persisting fissures after 8 weeks were offered a sphincterotomy or the alternate treatment. The authors don't describe using an intention-to-treat analysis. No patients were lost to follow-up. At the end of 8 weeks, 92% of patients treated with botulinum toxin were healed compared with 70% of those treated with nitroglycerine (number needed to treat = 5; 95% CI, 3-16). Since the lack of an intention-to-treat analysis tends to magnify treatment effects, it is possible that the real benefit may be smaller. Patients treated with botulinum were more likely to experience 3 weeks of "mild incontinence to flatus," while those treated with nitroglycerine were more likely to experience transient headaches.

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