Botulinum toxin was introduced as a therapeutic medication in the late 1980s. It revolutionized the treatment of dystonia by offering a localized method to relieve overactive muscle contractions. Botulinum toxin is injected directly into specific muscles where it acts to relax those muscles and reduce excessive muscle contractions.
Botulinum toxin is a biological product derived from the Clostridium botulinum bacterium. It binds to the nerves that lead to the muscle and prevents the release of acetylcholine which is a neurotransmitter that activates muscle contractions. When that messenger is blocked, muscle spasms are significantly reduced or eliminated.
Botulinum toxin is not a cure. Conditions with overactive muscles such as cervical dystonia and blepharospasm often require long term treatment. The benefits of each treatment may begin within 3 days to 2 weeks depending on the condition. The effects will usually last about 3 months. Treatments can continue as long as the condition continues to respond and you don’t experience an allergic reaction or any significant side effects.
The most frequent adverse reactions reported when using botulinum toxin to treat cervical dystonia include dysphagia (trouble swallowing 19%), cold or flu (12%), neck pain (11%) and headache (11%). When treating blepharospasm the most commonly reported adverse reactions were ptosis (droopy eyelids, 21%), inflammation of the cornea (6%) and dry eyes (6%).