Departments: Ask the Experts
Answers to reader questions about advances in treatment for peripheral neuropathy and tardive dyskinesia.
Theresa A. Zesiewicz, M.D., is director of University of South Florida Ataxia Research Center, founder of The Frances J. Zesiewicz Center and Foundation for Parkinson's Disease at USF, the director of the Parkinson's Disease and Movement Disorders Clinic at the James A. Haley Veteran's Administration Hospital in Tampa, FL, and a Fellow of the AAN.
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Your Questions Answered
Q What are the current treatments for tardive dyskinesia caused by long-term use of medications?
DR. THERESA A. ZESIEWICZ RESPONDS:
A Tardive dyskinesia is characterized by involuntary body movements commonly associated with therapeutic use of dopamine receptor blocking agents (DRBAs) for psychiatric conditions such as schizophrenia. Approximately 30 percent of people with psychiatric disorders who take DRBAs, also known as neuroleptics or antipsychotics, experience tardive dyskinesia.
The American Academy of Neurology (AAN) recently reviewed all the published studies on treatment of tardive dyskinesia (bit.ly/1hyurZE). The drug clonazepam and the supplement ginkgo biloba each appeared to improve tardive syndromes in several studies. Both treatments received a Level B recommendation (“should be considered as treatment”) at least over the course of three months. One antipsychotic medication, risperidone (Risperdal) was noted to improve symptoms of tardive dyskinesia in at least two studies, but it could not be recommended as treatment because it can worsen the underlying condition.
Other medications that may have some benefit in treating tardive dyskinesia include amantadine (Symmetrel), used to treat Parkinson's disease, and tetrabenazine (Xenazine), a drug approved by the U.S. Food and Drug Administration to treat chorea (another involuntary movement disorder) associated with Huntington's disease.
Switching from antipsychotic medications to atypical antipsychotics, thought to have a lower risk of causing tardive dyskinesia, could not be recommended due to conflicting study results.
Patients should consult with their healthcare providers before considering these medications, because of their possible side effects. For example, ginkgo biloba prevents blood from clotting and may interfere with the use of warfarin (Coumadin) and other blood thinners. Gingko biloba can also interact with some antidepressants. Clonazepam may cause fatigue and can be addictive. Potential side effects of tetrabenazine include depression and parkinsonism (tremors and muscular weakness associated with Parkinson's disease).
More clinical trials are needed to evaluate treatment of tardive dyskinesia. But conducting randomized controlled trials comparing an experimental drug with a sham (or placebo) therapy—the gold standard for research—can be challenging because patients taking an inactive medication could experience a relapse of their underlying psychiatric condition. Consultation with a healthcare provider, including a neurologist and movement disorder expert, is important to secure an accurate diagnosis and discuss possible treatments.