The treatment of cervical dystonia with botulinum toxins.

Botulinum neurotoxin (BoNT) treatment has been used extensively for the treatment of cervical dystonia. There are three established brands and two serotypes of BoNT commercially available in most of the world, and several additional brands are available in selected geographic regions. In most controlled studies, there is significant improvement following treatment for head posture, pain and disability. The common side effects of treatment include dysphagia, dry mouth, and neck weakness. Each brand and serotype is pharmacologically distinct. The dosing of each type differs, and no simple dose equivalency has been established. With repeated treatment, the development of immunoresistance is observed in a percentage of patients. However, it is likely that each brand and serotype may differ in immunogenic potential and occurrence of secondary unresponsiveness, an issue that is currently under active investigation.