Blinded randomized clinical trial of botulinum toxin versus isosorbide dinitrate ointment for treatment of anal fissure

Abstract

Abstract Background Nitric oxide donors such as isosorbide dinitrate (ISDN) are considered the first choice of treatment for anal fissure. After reports of the successful treatment of such fissures with botulinum toxin, this randomized blinded trial compared botulinum toxin with ISDN in the treatment of chronic anal fissure. Methods Patients were randomized to receive an injection of botulinum in the internal anal sphincter and a placebo ointment, or a placebo injection and ISDN ointment. The primary endpoint was macroscopic fissure healing after 4 months. Results After 4 months macroscopic healing of the fissures was noted in 14 of 37 patients in the botulinum group and 21 of 36 in the ISDN group. Pain scores were lower among patients who received ISDN, although the difference was not significant. Side-effects were similar in the two groups. Conclusion In contrast with previous reports on botulinum toxin as a therapeutic agent for anal fissure, this study found no advantage over treatment with a nitric oxide donor as regards fissure healing and fissure-related pain.