Other Medications Used to Treat Dystonia
Benzodiazepines
Benzodiazepines are a class of drugs that interfere with chemical activities in the nervous system and brain, serving to reduce communication between nerve cells. Consequently, such medications may relax muscles and ease symptoms associated with dystonia. Benzodiazepines are oral medications that may be used to treat focal, segmental, and generalized dystonias. Diazepam (Valium®) and clonazepam (Klonopin®) are two types of benzodiazepines that are most commonly used to treat dystonia. The major side effect of these drugs is drowsiness, which may be controlled by lowering the dose. At relatively high doses, side effects may include depression, personality changes, or, in severe cases, psychosis.
Baclofen
Baclofen (Lioresal®) is a drug that is used to treat individuals with spasticity. In addition, this drug has been administered to some patients with dystonia. Baclofen's primary site of action is the spinal cord where it reduces the release of neurotransmitters that stimulate muscle activity (GABA agonist stimulating GABAB autoreceptor). Baclofen has been used to treat both primary and secondary dystonias. This drug may be administered orally or via a surgically implanted pump that delivers the drug directly to the spinal cord (intrathecal baclofen).
Anticholinergics
Anticholinergic drugs block the action of the neurotransmitter acetylcholine, thereby deactivating muscle contractions. These drugs are administered orally and used to treat focal, segmental, and generalized dystonias. Trihexyphenidyl (Artane®) and diphenhydramine (Benadryl®) are the most common anticholinergic agents used to treat dystonia. This form of therapy may be more beneficial in children, as they are frequently able to tolerate higher doses of trihexphenidyl than adults. Greater therapeutic benefits may also occur in those patients who initiate drug therapy early during the course of their disease. Side effects may be severe, particularly at higher doses. These may include confusion, drowsiness, hallucinations, forgetfulness, personality changes, dry mouth, blurred vision, and urinary retention.
Dopamine-blocking agents/Dopamine-depleting agents
Dopamine-blocking or dopamine-depleting agents may be used to treat some patients with dystonia. The possible positive effect of these agents is a paradox since dopamine blockers may also cause dystonia. Nonetheless, these agents have been shown to be effective in some patients. Although not available in the United States, tetrabenazine is the most widely used dopamine-blocking agent. In some patients, tetrabenazine may be combined with lithium, which may help to lessen side effects such as slowed movements and depression. Other dopamine blockers are not as commonly used, since they may be more likely to evoke tardive dystonia. The neuroleptic drugs clozapine and olanzapine may be useful for the treatment of dystonia and may be less likely to cause tardive dystonia. See E-MOVE Article: Cervical dystonia: mixed results for clozapine.
