Clinicians should prescribe as much as 100 mg of tetrabenazine per day, between 300 and 400 mg of amantadine per day, or 200 mg of riluzole per day to treat patients with Huntington’s disease chorea, according to a new American Academy of Neurology (AAN) guideline published in the July 18 issue of Neurology. The drugs bring varying levels of benefit, and neurologists should discuss each medicine’s potential adverse events with patients, according to the guidelines. In particular, tetrabenazine entails risks of depression, suicidality, and parkinsonism, and riluzole may cause elevated liver enzymes.
Melissa J. Armstrong, MD, Assistant Professor of Neurology at the University of Maryland in Baltimore, and Janis M. Miyasaki, MD, Assistant Professor of Neurology at the University of Toronto, found 33 articles published through February 2011 regarding treatments for Huntington’s disease chorea in the MEDLINE and EMBASE databases. The investigators rated the articles using the AAN criteria for therapeutic classification.
The recommendations are based on the strength of the available evidence. The Unified Huntington’s Disease Rating Scale was the studies’ main outcome measure, but the studies did not define a clinically important change on this scale.
The investigators observed no difference in video-rated chorea scores between amantadine and placebo, but concluded that a modest effect of amantadine on chorea could not be excluded.
“Clinicians may prescribe nabilone for modest decreases in Huntington’s disease chorea … but information is insufficient to recommend long-term use, particularly given abuse potential concerns,” said the researchers. Ethyl-EPA, minocycline, and creatine are not recommended for very important improvements in Huntington’s disease chorea, but may provide moderate benefits. Coenzyme Q10 is not recommended for moderate improvements, but may provide modest benefits, according to the investigators. “Data are insufficient to make recommendations regarding use of clozapine, other neuroleptics, or donepezil for Huntington’s disease chorea treatment,” the researchers concluded.
Armstrong MJ, Miyasaki JM. Evidence-based guideline: Pharmacologic treatment of chorea in Huntington disease. Neurology. 2012 Jul 18; [Epub ahead of print].