Topical nitrates and the higher doses of botulinum toxin for chronic anal fissure.

Background/aims: Combined BT-A (botulinum toxin A) therapy and local application of nitrates can be more effective than BT-A alone for chronic anal fissure treatment, but so far the optimal dose of BT-A is not known. The aim of our study was to learn if BT-A doses higher than those used so far could change the outcome of fissure treatment.

Methodology: We enrolled 14 consecutive patients suffering from idiopathic chronic anal fissure who did not respond to previous local treatment of nitric oxide donor and subsequent BT-A therapy (25 U of Botox).