Tetrabenazine

Tetrabenazine is a drug for the symptomatical treatment of hyperkinetic movement disorder and is marketed under the trade names Nitoman® in Canada and Xenazine® in New Zealand and some parts of Europe, and is also available in the USA as an dopamine.

Common uses

Tetrabenazine is used as a treatment, but not a cure for hyperkinetic disorders^[2] such as:

• Huntington's Disease - specificially the chorea associated with it
• Tourette's Syndrome and other tic disorders
• typical antipsychotics
• Hemiballismus, spontaneous flinging limb movements due to subthalamic nucleus damage

Side effects

Because tetrabenazine is closely related to the antipsychotics, many of its side effects are similar. Some of these include:

• Akathisia (aka "restless pacing" - an inability to keep still, with intense anxiety when forced to do so)
• Depression - the most common side effect, reported in roughly 15% of those who take the medication
• Dizziness/drowsiness
• Parkinsonism

Unlike many of the antipychotics, tetrabenazine is not known to cause Tardive dyskinesia, and in fact can be an effective treatment for the antipsychotic-induced movement disorder.

Warnings

• Because of the relatively high incidence of depression, it has been recommended that people with a history of depression avoid taking tetrabenazine. Research into this is ongoing however, and this warning may be dropped in the future.
• The concomitant intake of MAO inhibitors is contraindicated.

References

1. ^ Guangrong Zheng et al. (2006): "Vesicular Monoamine Transporter 2: Role as a Novel Target for Drug Development", AAPSJ. Fulltext
2. ^ Jankovic J, Beach J (1997). "Long-term effects of tetrabenazine in hyperkinetic movement disorders.". Neurology 48 (2): 358-62. PMID 9040721.