Tetrabenazine

What is Tetrabenazine?

Tetrabenazine (XENAZINE) is a vesicular monoamine transporter 2 (VMAT) inhibitor used to treat the involuntary movements (chorea) of Huntington’s disease.

What are the uses of this medicine?

• This medicine used used to treat the involuntary movements (chorea) of Huntington’s disease.
• XENAZINE does not cure the cause of the involuntary movements, and it does not treat other symptoms of Huntington’s disease, such as problems with thinking or emotions.

How does this medicine work?

• Tetrabenazine (tet" ra ben' a zeen) is an inhibitor of synaptic vesicular monoamine transporter 2 (VMAT2), the inhibition of which causes a depletion of neuroactive monoamines (serotonin, norepinephrine and particularly dopamine) in nerve terminals.
• The reduction in these active neurotransmitters results in a decrease in spontaneous jerk-like movements of the extremities, trunk, face and neck (chorea) that are typical of patients with degenerative neurologic conditions such as Huntington disease.
• Tetrabenazine, however, does not prevent the progression or alter the outcome of these diseases.

Who Should Not Use this medicine ?

This medicine cannot be used in patients who:

• are depressed or have thoughts of suicide.
• have liver problems.
• are taking a monoamine oxidase inhibitor (MAOI) medicine.
• are taking reserpine. Do not take medicines that contain reserpine (such as Serpalan and Renese-R) with XENAZINE. If your doctor plans to switch you from taking reserpine to XENAZINE, you must wait at least 20 days after your last dose of reserpine before you start taking XENAZINE.

What drug interactions can this medicine cause?

• A reduction in XENAZINE dose may be necessary when adding a strong CYP2D6 inhibitor (e.g., fluoxetine, paroxetine, quinidine) in patients maintained on a stable dose of XENAZINE. The daily dose of XENAZINE should not exceed 50 mg/day and the maximum single dose of XENAZINE should not exceed 25 mg in patients taking strong CYP2D6 inhibitors.
• XENAZINE and reserpine should not be used concomitantly.
• XENAZINE should not be used in combination with an MAOI, or within a minimum of 14 days of discontinuing therapy with an MAOI.
• Avoid use of alcohol or other sedating drugs may have additive effects and worsen sedation and somnolence.
• XENAZINE causes a small prolongation of QTc (about 8 msec), concomitant use with other drugs that are known to cause QTc prolongation should be avoided, these including antipsychotic medications (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone), antibiotics (e.g., moxifloxacin), Class 1A (e.g., quinidine, procainamide) and Class III (e.g., amiodarone, sotalol) antiarrhythmic medications or any other medications known to prolong the QTc interval.
• Avoid concomitant use of XENAZINE and dopamine antagonists or antipsychotics (e.g., chlorpromazine, haloperidol, olanzapine, risperidone, thioridazine, ziprasidone).
• XENAZINE is contraindicated in patients currently taking deutetrabenazine or valbenazine.

Is this medicine FDA approved?

• It was approved for use in the United States in 2017.

How should this medicine be used?

Recommended Dosageː

• Individualization of dose with careful weekly titration is required. The 1st week’s starting dose is 12.5 mg daily; 2nd week, 25 mg (12.5 mg twice daily); then slowly titrate at weekly intervals by 12.5 mg to a tolerated dose that reduces chorea.
• Doses of 37.5 mg and up to 50 mg/day should be administered in three divided doses per day with a maximum recommended single dose not to exceed 25 mg.

Patients requiring doses above 50 mg/day should be genotyped for the drug metabolizing enzyme CYP2D6 to determine if the patient is a poor metabolizer (PM) or an extensive metabolizer (EM).

• Maximum daily dose in PMs: 50 mg with a maximum single dose of 25 mg.
• Maximum daily dose in EMs and intermediate metabolizers (IMs): 100 mg with a maximum single dose of 37.5 mg.

Administration

• XENAZINE is a tablet that you take by mouth.
• Take XENAZINE exactly as prescribed by your doctor.
• You may take XENAZINE with or without food.
• Your doctor will increase your dose of XENAZINE each week for several weeks, until you and your doctor find the best dose for you.
• If you stop taking XENAZINE or miss a dose, your involuntary movements may return or worsen in 12 to 18 hours after the last dose.
• Before starting XENAZINE, you should talk to your healthcare provider about what to do if you miss a dose. If you miss a dose and it is time for your next dose, do not double the dose.
• Tell your doctor if you stop taking XENAZINE for more than 5 days. Do not take another dose until you talk to your doctor.
• If your doctor thinks you need to take more than 50 mg of XENAZINE each day, you will need to have a blood test to see if it is safe for you.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As Tablets: 12.5 mg non-scored and 25 mg scored

This medicine is available in fallowing brand namesː

• XENAZINE

What side effects can this medication cause?

The most common side effects of this medicine include:

• sleepiness (sedation)
• trouble sleeping
• depression
• tiredness (fatigue)
• anxiety
• restlessness
• agitation
• nausea

XENAZINE can cause serious side effects, including:

• Depression, suicidal thoughts, or actions
• Neuroleptic Malignant Syndrome (NMS)
• Parkinsonism
• Restlessness
• Irregular heartbeat
• Dizziness due to blood pressure changes when you change position (orthostatic hypotension)

What special precautions should I follow?

• Sleepiness (sedation) is a common side effect of XENAZINE. While taking XENAZINE, do not drive a car or operate dangerous machinery until you know how XENAZINE affects you.
• Drinking alcohol and taking other drugs that may also cause sleepiness while you are taking XENAZINE may increase any sleepiness caused by XENAZINE.
• Patients with Huntington’s disease are at increased risk for depression, suicidal ideation or behaviors (suicidality). XENAZINE increases the risk for suicidality in patients with HD. Periodically reevaluate the benefit and potential for adverse effects such as worsening mood, cognition, rigidity, and functional capacity.
• Do not exceed 50 mg/day and the maximum single dose should not exceed 25 mg if administered in conjunction with a strong CYP2D6 inhibitor (e.g., fluoxetine, paroxetine).
• A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with XENAZINE. Discontinue if this occurs.
• XENAZINE may increase the risk of akathisia, restlessness, and agitation. Reduce dose or discontinue if occurs.
• XENAZINE causes a small increase (about 8 msec) in the corrected QT (QTc) interval. Not recommended in combination with other drugs that prolong QTc.

What to do in case of emergency/overdose?

• Adverse reactions associated with XENAZINE overdose include acute dystonia, oculogyric crisis, nausea and vomiting, sweating, sedation, hypotension, confusion, diarrhea, hallucinations, rubor, and tremor.

Management for overdosage:

• Treatment should consist of those general measures employed in the management of overdosage with any CNS-active drug.
• General supportive and symptomatic measures are recommended.
• Cardiac rhythm and vital signs should be monitored.
• In managing overdosage, the possibility of multiple drug involvement should always be considered.
• The physician should consider contacting a poison control center on the treatment of any overdose.

Can this medicine be used in pregnancy?

• There are no adequate data on the developmental risk associated with the use of XENAZINE in pregnant women.

Can this medicine be used in children?

• Safety and effectiveness in pediatric patients have not been established.

What are the active and inactive ingredients in this medicine?

Active ingredient:

• TETRABENAZINE

Inactive ingredients:

• LACTOSE, UNSPECIFIED FORM
• magnesium stearate
• starch, corn
• talc

Who manufactures and distributes this medicine?

Manufactured by: Recipharm Fontaine SAS Rue des Prés Potets 21121 Fontaine-lés-Dijon, France

Manufactured for: Lundbeck Deerfield, IL 60015 USA

What should I know about storage and disposal of this medication?

• Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F).

• Dailymed label info on Tetrabenazine
• FDA Tetrabenazine

Tetrabenazine Resources
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