Dystonia

Pharmacologic Treatment of Dystonia

There are a number of treatment options available to treat dystonia. Drugs may be used alone or in combination. In addition, they may be combined with other forms of treatment.

Botulinum toxin (BoNT)
Botulinum toxin (BoNT) is a biological therapeutic agent that acts against dystonia. Botulinum toxin is a toxic protein that is produced by the bacterium Clostridium botulinum. The use of botulinum toxin (BoNT) represents a significant advance in the treatment of dystonia. This toxin is known to cause botulism, a deadly form of food poisoning that is contracted through the ingestion of contaminated food products. However, when a minute amount of commercially prepared BoNT is injected directly into an overactive muscle, it relaxes that muscle.

BoNT acts to block the release of acetylcholine, a neurotransmitter responsible for activation of muscle contraction. Thus, BoNT decreases inappropriate or excessive muscle contractions, allowing the affected area (e.g., arm, neck, leg, eyelid, etc.) to assume a more normal position or posture.

There are seven forms (serotypes) of botulinum toxin; namely, types A, B, C, D, E, F, and G. Each serotype of has a distinct structure and mechanism of action. In the United States, four BoNT products have been approved by the U.S. Food and Drug Administration (FDA). They are BOTOX® (a BoNT-A product produced by Allergan, Inc.), Dysport (a BoNT-A product produced by Ipsen, Ltd.), Xeomin (a BoNT-A product produced by Merz Pharmaceuticals), and Myobloc™ (a BoNT-B product produced by Solstice Neurosciences). Each BoNT product is unique, with its own safety, efficacy, and immunogenicity profile.