How to target psychiatric symptoms of Huntington’s disease

Tetrabenazine, the only FDA-approved drug for treating Huntington’s disease (HD), is a dopamine-depleting agent given to control chorea. In a 12-week, randomized, double-blind, placebo-controlled clinical trial, tetrabenazine was shown to be effective in HD patients.^a Treatment with tetrabenazine results in symptomatic improvement of chorea, but does not slow or alter the course of the disease. Tetrabenazine can provide relief from choreiform movements, but these benefits should be balanced with the risks of depression and suicidality.^a Tetrabenazine is known to prolong QTc interval, and should be used with caution in combination with other drugs that have the potential to do the same (eg, antipsychotics).^a

Several case reports have found an association between tetrabenazine and development of neuroleptic malignant syndrome (NMS).^b-d Be aware of the clinical characteristics of NMS—mental status change, rigidity, fever, and dysautonomia—and use caution when starting patients taking tetrabenazine on antipsychotics or other agents known to cause NMS.

Amantadine also has been used to treat chorea in HD patients who are unable to tolerate tetrabenazine or antipsychotics. Our neurologists sometimes have found it to be beneficial in patients with juvenile-onset HD because these patients often have debilitating dystonia. Be aware that amantadine is known to precipitate or worsen psychosis.^e