New AAN Guideline on Treatment of Chorea in Huntington's

Megan Brooks

July 18, 2012

July 18, 2012 — Tetrabenazine, amantadine, and riluzole can be helpful in easing chorea symptoms in patients with Huntington's disease (HD), and nabilone may also be considered to treat chorea, according to a new guideline from the American Academy of Neurology (AAN).

The jerky, random, uncontrollable movements characteristic of chorea can be disabling, worsen weight loss, and increase the risk of falls. "To date, there have been few evidenced-based guidelines for HD, so we chose to review treatment options for chorea, the HD symptom with the most pharmacologic studies," lead guideline author Melissa J. Armstrong, MD, from the Department of Neurology, University of Maryland, in Baltimore, told Medscape Medical News.

Melissa J. Armstrong, MD

The guideline — Pharmacologic Treatment of Chorea in Huntington's Disease — was published July 18 in Neurology.

Based on the evidence, the guideline recommends that if HD chorea requires treatment, "clinicians may prescribe tetrabenazine (up to 100 mg/day), amantadine (300 to 400 mg/day), or riluzole (200 mg/day) (Level B) for varying degrees of expected benefit."

The guideline also notes that treatment with nabilone may yield "modest decreases" in chorea (Level C), "but information is insufficient to recommend long-term use, particularly given abuse potential concerns (Level U)."

However, Dr. Armstrong commented that the drugs covered by this guideline are not often used clinically, whereas neuroleptics are used clinically but are not included in the guideline because little evidence is available from clinical trials to support their use.

Individual Decision

"Evidence suggests that if chorea requires treatment in HD, tetrabenazine can be helpful for achieving important reductions in chorea," Dr. Armstrong commented. "Tetrabenazine is the only drug with US Food and Drug Administration approval for treating HD chorea. Additionally, the drugs riluzole and amantadine can be helpful, and nabilone may be helpful for treating HD chorea to varying degrees. Each drug has limitations in terms of cost and adverse effects."

"When patients and physicians decide that chorea needs treatment, they need to individually weigh the evidence and each option's risks and benefits to decide what is right for them," Dr. Armstrong added. The guideline advises discussing and monitoring for possible adverse events, "particularly depression/suicidality and parkinsonism with tetrabenazine and elevated liver enzymes with riluzole."

The guideline also states that clinicians "should not prescribe riluzole 100 mg/day for moderate short-term benefits (Level B negative) or for any long-term (3-year) HD antichoreic goals (Level B negative)."

The guideline notes that ethyl-EPA, minocycline, creatine, and coenzyme Q10 are unlikely to be very helpful for HD chorea, and data are insufficient to make recommendations regarding the use of neuroleptics or donepezil for HD chorea treatment.

Some Surprises

Dr. Armstrong told Medscape Medical News, "Two things will come as a surprise to the average clinician: the lack of identified evidence for one of the most common drug classes used to treat chorea, and the positive evidence for drugs not commonly used."

"Typical and atypical neuroleptic agents," she explained, "are often prescribed for both behavioral symptoms and chorea in HD. However, no neuroleptic studies meeting the guideline process inclusion criteria were identified. Because the AAN uses a strict evidence-based methodology for its guidelines, we could not make a recommendation for or against the use of neuroleptic agents for chorea."

Additionally, Dr. Armstrong said that the 3 drugs for which the guideline makes a positive recommendation — amantadine, riluzole, and nabilone — are not often used for HD chorea clinically. "For the systematic review, we identified all HD studies with a pharmacologic intervention and chorea as a primary or secondary endpoint. Following the evidence-based process, we present the data that these drugs may have some antichoreic benefit regardless of their current degree of use."

Dr. Armstrong noted that "more research is needed to understand what change scores are clinically meaningful on chorea scales. It is possible that some of the improvements seen in studies of drugs for chorea were statistically significant but not clinically meaningful."

The guideline was developed with financial support from the American Academy of Neurology. None of the authors received reimbursement, honoraria, or stipends for their participation in its development.

Neurology. 2012;79:597-603. AAN Guidelines

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