Current status and prospects of medical therapy for dystonia]

The goal of medical therapy for primary dystonia is conservative. While botulinum toxin (BTX) therapy is a first choice for blepharospasm and cervical dystonia, medical therapy is selected as such for other types of dystonia. As oral medications, trihexyphenidyl and benzodiazepines are most frequently used. Muscle relaxants are also commonly used, but dopamine antagonists are not recommended because of the risk of inducing tardive dyskinesia. For childhood-onset generalized dystonia, levodopa should be considered to rule out levodopa-responsive dystonia. Mexiletine is reported to be effective not only for bleharospasm and cervical dystonia but for focal limb dystonia. To improve the therapeutic performance of BTX therapy for blepharospasm, it is recommended that corrugator supercilii and procerus muscles, as well as orbicularis oculi muscle, be added as target muscles. To improve the therapeutic performance of BTX therapy for cervical dystonia, it is recommended that this therapy be started as early as possible, especially within one year of illness, and that levator scapulae muscle be added as target if necessary. To improve usefulness of medical therapy for dystonia, its strategy must be standardized, and more useful therapies must be positively adopted. Algorithm for treatment of dystonia must also be established and generalized.