Isosorbide dinitrate ointment vs botulinum toxin A (Dysport (R)) as the primary treatment for chronic anal fissure: a randomized multicentre study

AimNitric oxide donors, such as isosorbide dinitrate ointment (ISDN), are considered as first-choice agents in the treatment of chronic anal fissure. Injection with botulinum toxin A in the internal anal sphincter is often used as a second-line therapy, although it may give better results and fewer side effects than nitric oxide donors. The aim of this randomized clinical trial was to investigate whether botulinum toxin A (Dysport((R))) is more effective than ISDN in the primary treatment of chronic anal fissure.

MethodFrom April 2005 until October 2009, 60 patients (32 men) with a median age of 42 (25-82) years were randomized to receive either ISDN 10mg/ml (1%) (n=33) or injection with 60 units of Dysport((R)) (n=27). The primary end-point was the percentage of complete fissure healing after 8weeks.

ResultsAfter a median of 9weeks complete fissure healing was noted in 18 of 27 patients in the Dysport((R)) group and in 11 of 33 patients in the ISDN group (P=0.010). Absolute improvement of pain scores after 9weeks was similar in both groups (P=0.733). Patients treated with Dysport((R)) had fewer side effects than patients treated with ISDN (P=0.028). Of the patients with a healed fissure, 28% of the Dysport((R)) group and 50% of the ISDN group had a recurrence within 1year (P=0.286; hazard ratio 2.08; 95% CI=0.54-7.97).

ConclusionDysport((R)) is more effective than ISDN ointment and has fewer side effects in the primary treatment of chronic anal fissure. The recurrence rate within 1year in both treatment groups is high.