Chronic anal fissure: botulinum toxin type A injection

About botulinum toxin type A injection

When used to treat chronic anal fissure, botulinum toxin type A is usually injected into the muscle around the anus (back passage). The aim is to help reduce excess muscle tension in this muscle, which is thought to help the fissure to heal naturally.

There are 6 brands of botulinum toxin type A (Azzalure, Bocouture, Botox, Dysport, Vistabel and Xeomin) currently licensed in the UK to treat many different medical conditions, including a lot of conditions associated with muscle spasms (uncontrolled muscle contractions). However, no brand of botulinum toxin type A has a UK licence to treat chronic anal fissure. So when it is used to treat chronic anal fissure it is described as being used 'off-label'.

Various different amounts of botulinum toxin type A have been used in studies of chronic anal fissure, injected at various places around the fissure. This usually involves 1 or 2 injections into either only one side of the fissure or in both sides. In the UK, the injections are usually given under a local or general anaesthetic in an operating theatre.