How does botulinum toxin work?

Author: SCIRE Community Team | Reviewer: Patricia Mills | Published: 10 November 2017 | Updated: ~

A black and white cartoon diagram of a neural synapse

When botulinum toxin is injected into a muscle, it blocks the nerves to the muscles from releasing a chemical called acetylcholine. Acetylcholine makes muscles contract (tense). When its release is blocked, the muscles are unable to contract, causing weakness or paralysis. In a muscle with spasticity, botulinum toxin can help to decrease muscle spasms.

Illustration accompanying How does botulinum toxin work?

Botulinum toxin can be used to treat overactive (reflex) bladder problems for similar reasons. These bladder problems happen when the bladder muscle or the bladder sphincters spasm, preventing emptying or causing random emptying of urine (detrusor hyperreflexia). The injection of botulinum toxin into these muscles reduces muscle spasms, which may help to treat these problems.