Botulinum Toxin for Anal Fissure

Anal fissure may become a chronic problem leading to a significant negative effect on quality of life. To date, surgical intervention (lateral sphincterotomy) has been used to some advantage, but it is compromised by the not infrequent complication of incontinence (8-30%), which may be permanent.

The authors studied the efficacy of local injection of botulinum toxin, divided as two injections of 0.4 mL containing 20 U botulinum toxin A (Botox, Allergan) administered on a single visit, vs. placebo (saline) in 30 patients. All injections were done as an outpatient procedure into the internal rectal sphincter with a 27 gauge needle, without local anesthesia, and were reportedly "painless."

All of the patients who received active drug demonstrated healed fissures by four months time, though a few required retreatment with a higher dose of Botox. Symptomatic relief paralleled macroscopic fissure healing. There were no significant local or systemic consequences of Botox therapy.

Topical nitroglycerin ointment has also recently been advocated for treatment of anal fissure; however, success rates for fissure resolution are not as great (47-85% resolution by 6 weeks), and side effects typical of nitroglycerin applied at other body sites may be problematic. A head-to-head trial of nitroglycerin with botulinum toxin A is suggested. Botulinum toxin A is a promising new therapy for anal fissure.

Maria G, et al. N Engl J Med 1998; 338:217-220.