Botulinum toxin (Botox)

Abstract

Botulinum toxin (Botox) is a neurotoxin produced by the bacterium Clostridium botulinum. There are seven types of Botox (A–G) which bind and cleaves one of several neuronal cellular proteins including SNAP-25, syntaxin or VAMP/synaptobrevin. The net result is the inhibition of the release of acetylcholine (Ach) from the terminal bouton of motor neurons resulting in muscle weakness or paralysis. The duration of action of Botox depends on the time taken for cellular mechanisms to regenerate the cleaved proteins and restore the ability for neuronal Ach release, typically 3–6 months. Botox has several medical indications and is effective in reducing pain and/or muscle activity in chronic migraine, myofascial pain, orofacial movement disorders, neuropathic pain, trigeminal neuralgia (TN) and bruxism. Additionally it can be used to treat sialorrhea and Frey syndrome. The injection technique is very simple and can be performed with or without electromyography depending on the indication. Complications relating to the use of Botox are extremely rare and include allergic reaction and unanticipated weakness/paralysis of adjacent muscles.