Botulinum toxin B

Botulinum Toxin B

Botulinum toxin B is one of the seven serotypes of botulinum toxin, a neurotoxic protein produced by the bacterium Clostridium botulinum. It is used in both medical and cosmetic applications to temporarily reduce muscle activity.

Mechanism of Action

Botulinum toxin B works by inhibiting the release of the neurotransmitter acetylcholine at the neuromuscular junction. This inhibition occurs through the cleavage of synaptobrevin, a protein essential for the fusion of synaptic vesicles with the presynaptic membrane. As a result, muscle contraction is reduced or eliminated, leading to the relaxation of the targeted muscles.

Medical Uses

Botulinum toxin B is primarily used in the treatment of cervical dystonia, a condition characterized by abnormal neck movements and postures. It is also used off-label for other conditions such as sialorrhea (excessive drooling) and spasticity.

Cervical Dystonia

In patients with cervical dystonia, botulinum toxin B is injected into the affected neck muscles to alleviate symptoms. The toxin's effect typically begins within a few days and can last for several months, after which repeat injections may be necessary.

Sialorrhea

Botulinum toxin B can be used to reduce excessive salivation by injecting it into the salivary glands. This application is particularly beneficial for patients with neurological disorders that cause drooling.

Cosmetic Uses

While botulinum toxin B is less commonly used for cosmetic purposes compared to botulinum toxin A, it can still be employed to reduce the appearance of facial wrinkles by relaxing facial muscles.

Side Effects

Common side effects of botulinum toxin B include dry mouth, dysphagia (difficulty swallowing), and injection site pain. More serious side effects, though rare, can include generalized muscle weakness and allergic reactions.

Comparison with Botulinum Toxin A

Botulinum toxin B differs from botulinum toxin A in its molecular structure and duration of action. While both serotypes are effective in reducing muscle activity, botulinum toxin A is more commonly used due to its longer duration of effect and broader range of approved indications.

History

Botulinum toxin B was first approved for medical use in the United States in 2000. It is marketed under the brand name Myobloc in the U.S. and NeuroBloc in Europe.

See Also

• Botulinum toxin
• Clostridium botulinum
• Neuromuscular junction

External Links

• FDA - Botulinum Toxin Products
• NCBI - Botulinum Toxin B