Last reviewed 2026-05-13 · How we verify

Xenazine (TETRABENAZINE)

Xenazine works by blocking the reuptake of dopamine and other neurotransmitters into synaptic vesicles, reducing their release and alleviating symptoms of Huntington's chorea.

Xenazine (Tetrabenazine) is a small molecule Vesicular Monoamine Transporter 2 Inhibitor developed by Valeant Pharms North and currently owned by Bausch. It targets the synaptic vesicular amine transporter to treat Huntington's chorea, a disorder characterized by involuntary movements. Approved by the FDA in 2008, Xenazine is available as a generic medication with 11 manufacturers. As an off-patent medication, it is no longer protected by active patents. Key safety considerations include the risk of depression, anxiety, and sleep disorders.

At a glance

Mechanism of action

The precise mechanism by which tetrabenazine tablets exerts its anti-chorea effects is unknown but is believed to be related to its effect as reversible depletor of monoamines (such as dopamine, serotonin, norepinephrine, and histamine) from nerve terminals. Tetrabenazine reversibly inhibits the human vesicular monoamine transporter type (VMAT2) (Ki 100 nM), resulting in decreased uptake of monoamines into synaptic vesicles and depletion of monoamine stores. Human VMAT2 is also inhibited by dihydrotetrabenazine (HTBZ), mixture of -HTBZ and -HTBZ. and -HTBZ, major circulating metabolites in humans, exhibit high in vitro binding affinity to bovine VMAT2. Tetrabenazine exhibits weak in vitro binding affinity at the dopamine D2 receptor (Ki 2100 nM).

Approved indications

• Huntington's chorea

Boxed warnings

• WARNING: DEPRESSION AND SUICIDALITY Tetrabenazine can increase the risk of depression and suicidal thoughts and behavior (suicidality) in patients with Huntington’s disease. Anyone considering the use of tetrabenazine must balance the risks of depression and suicidality with the clinical need for control of chorea. Close observation of patients for the emergence or worsening of depression, suicidality, or unusual changes in behavior should accompany therapy. Patients, their caregivers, and families should be informed of the risk of depression and suicidality and should be instructed to report behaviors of concern promptly to the treating physician. Particular caution should be exercised in treating patients with a history of depression or prior suicide attempts or ideation, which are increased in frequency in Huntington’s disease. Tetrabenazine is contraindicated in patients who are actively suicidal, and in patients with untreated or inadequately treated depression [see Contraindications ( 4 ), Warnings and Precautions ( 5.1 )]. WARNING: DEPRESSION AND SUICIDALITY See full prescribing information for complete boxed warning . Increases the risk of depression and suicidal thoughts and behavior (suicidality) in patients with Huntington’s disease ( 5.1 ) Balance risks of depression and suicidality with the clinical need for control of chorea when considering the use of tetrabenazine tablets ( 5.2 ) Monitor patients for the emergence or worsening of depression, suicidality, or unusual changes in behavior ( 5.1 ) Inform patients, caregivers and families of the risk of depression and suicidality and instruct to report behaviors of concern promptly to the treating physician ( 5.1 ) Exercise caution when treating patients with a history of depression or prior suicide attempts or ideation ( 5.1 ) Tetrabenazine tablets are contraindicated in patients who are actively suicidal, and in patients with untreated or inadequately treated depression ( 4 , 5.1 )

Common side effects

• Sedation/somnolence
• Fatigue
• Insomnia
• Depression
• Akathisia
• Anxiety/anxiety aggravated
• Nausea
• Irritability
• Decreased appetite
• Obsessive reaction
• Parkinsonism/bradykinesia
• Dizziness

Drug interactions

• High Risk QT Prolonging Agents
• tranylcypromine

Key clinical trials

• Xenazine in Late Dyskinetic Syndrome With Neuroleptics (PHASE3)
• Effect of Tetrabenazine on Stroop Interference in HD (PHASE4)
• Efficacy, Safety, and Tolerability of Valbenazine for the Treatment of Chorea Associated With Huntington Disease (PHASE3)
• Compassionate Use of Tetrabenazine in the Treatment of Abnormal Movements
• A Pilot Study Assessing Impulsivity in Patients With Huntington's Disease on Xenazine (Tetrabenazine) (PHASE4)
• Alternatives for Reducing Chorea in Huntington Disease (PHASE3)
• Excessive Crying in Children With Cerebral Palsy and Communication Deficits (PHASE4)
• A Study of the Effectiveness and Safety of Tetrabenazine MR in Pediatric Subjects With Tourette's Syndrome (PHASE2)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Xenazine CI brief — competitive landscape report
• Xenazine updates RSS · CI watch RSS
• Bausch Health portfolio CI