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

Aim Nitric 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 ( D ysport ® ) is more effective than ISDN in the primary treatment of chronic anal fissure. Method From A pril 2005 until O ctober 2009, 60 patients (32 men) with a median age of 42 (25–82) years were randomized to receive either ISDN 10 mg/ml (1%) ( n  = 33) or injection with 60 units of D ysport ® ( n  = 27). The primary end‐point was the percentage of complete fissure healing after 8 weeks. Results After a median of 9 weeks complete fissure healing was noted in 18 of 27 patients in the D ysport ® group and in 11 of 33 patients in the ISDN group ( P  = 0.010). Absolute improvement of pain scores after 9 weeks was similar in both groups ( P  = 0.733). Patients treated with D ysport ® had fewer side effects than patients treated with ISDN ( P  = 0.028). Of the patients with a healed fissure, 28% of the D ysport ® group and 50% of the ISDN group had a recurrence within 1 year ( P  = 0.286; hazard ratio 2.08; 95% CI  = 0.54–7.97). Conclusion Dysport ® is more effective than ISDN ointment and has fewer side effects in the primary treatment of chronic anal fissure. The recurrence rate within 1 year in both treatment groups is high.