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

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.

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). They were offered a local nitroglycerin treatment. In failure cases patients received the greater doses of BT-A (50 U of Botox).

In all 11 patients with chronic anal fissure who applied nitroglycerin after BT-A injection, an effect on the internal anal sphincter relaxation was observed but fissure healing after topical nitroglycerin occurred only in 1 case. Of 13 patients with chronic anal fissure who received 50 U of BT-A no healing was reported in 6 cases. One male from this group received a greater dose (100 U of Botox) and then the fissure healed.

The effect of topical nitrates on internal anal sphincter relaxation after botulinum toxin injection is not the last line for nonsurgical treatment of chronic anal fissure. Always we ought to consider using the next greater dose of BT-A before surgical treatment.