|Trade names||Xenazine, Xentra, Nitoman, others|
|AHFS/Drugs.com||Consumer Drug Information|
|By mouth (tablets)|
|Bioavailability||Low, extensive first pass effect|
|Elimination half-life||10 hours parent compound (2 to 8 hours active metabolites)|
|Excretion||Renal (~75%) and fecal (7–16%)|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||317.429 g·mol−1|
|3D model (JSmol)|
Tetrabenazine is a drug for the symptomatic treatment of hyperkinetic movement disorders. It is sold under the brand names Nitoman and Xenazine among others. On August 15, 2008, the U.S. Food and Drug Administration approved the use of tetrabenazine to treat chorea associated with Huntington's disease. Although other drugs had been used "off label," tetrabenazine was the first approved treatment for Huntington's disease in the U.S. The compound has been known since the 1950s.
Tetrabenazine is used as a treatment, but not as a cure, for hyperkinetic disorders such as:
Tetrabenazine has been used as an antipsychotic in the treatment of schizophrenia, both in the past and in modern times.
The most common adverse reactions, which have occurred in at least 10% of subjects in studies and at least 5% greater than in subjects who received placebo, have been: sedation or somnolence, fatigue, insomnia, depression, suicidal thoughts, akathisia, anxiety and nausea.
There is a boxed warning associated with the use of tetrabenazine:
See also: Monoamine-depleting agent
The precise mechanism of action of tetrabenazine is unknown. Its anti-chorea effect is believed to be due to a reversible depletion of monoamines such as dopamine, serotonin, norepinephrine, and histamine from nerve terminals. Tetrabenazine reversibly inhibits vesicular monoamine transporter 2, resulting in decreased uptake of monoamines into synaptic vesicles, as well as depletion of monoamine storage.