Botulinum toxin
The most commonly used treatment for spasmodic torticollis is the use of botulinum toxin injection in the dystonic musculature. Botulinum toxin type A is most often used; it prevents the release of acetylcholine from the presynaptic axon of the motor end plate, paralyzing the dystonic muscle. By disabling the movement of the antagonist muscle, the agonist muscle is allowed to move freely. With botulinum toxin injections, patients experience relief from spasmodic torticollis for approximately 12 to 16 weeks. There are several type A preparations available worldwide; however Botox and Dysport are the only preparations approved by the U.S. Food and Drug Administration (FDA) for clinical use in the United States.