Tetrabenazine

Tetrabenazine tablets are used to treat involuntary movements (chorea) caused by Huntington's disease, which is a rare, inherited disease that causes nerve cells in the brain to breakdown and die. Tetrabenazine helps control involuntary body movement of Huntington’s disease, but does not help the psychiatric and thinking (cognitive) symptoms, and it does not cure the disease.

Tetrabenazine is thought to work by changing the level of natural substances in the brain that control muscle movement.

Tetrabenazine (Brand name: Xenazine) is from the class of medications called vesicular monoamine transporter 2 (VMAT2) inhibitors. Tetrabenazine has its effect by blocking the protein VMAT2 which lowers the amount of messenger chemicals (dopamine, serotonin, norepinephrine, and histamine) in the nerve cells, which is how it is thought to help control involuntary body movements.

Take tetrabenzaine exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use tetrabenazine in larger or smaller amounts or for longer than recommended.

You may take tetrabenazine tablets with or without food.

Call your doctor if your symptoms do not improve, or if they get worse.

You should not stop using tetrabenazine suddenly or your symptoms may return. Talk to your doctor before you stop taking this medicine.

You may have depression or thoughts about suicide while taking tetrabenazine. Stay alert to changes in your mood or symptoms. Report any new or worsening symptoms to your doctor.

You should not use tetrabenazine if you have severe or untreated depression, suicidal thoughts, liver disease, or if you have taken reserpine in the past 20 days.

Do not use tetrabenazine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

You should not use tetrabenazine if you are allergic to it or any of the inactive ingredients, or if you have:

• severe or untreated depression;
• suicidal thoughts;
• liver disease; or
• if you have taken reserpine in the past 20 days.

Do not use tetrabenazine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

To make sure tetrabenazine is safe for you, tell your doctor if you have:

• depression, an emotional disorder, or mental illness;
• a history of suicidal thoughts or actions;
• past or present breast cancer;
• heart disease or heart rhythm disorder;
• a personal or family history of long QT syndrome; or
• if you recently had a heart attack.

Taking tetrabenazine may increase your risk of depression or thoughts about suicide. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Pregnancy

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Breastfeeding

It is not known whether tetrabenazine passes into breast milk or if it could harm a nursing baby. You should not breastfeed while using this medicine.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Tetrabenazine may cause serious side effects. Call your doctor at once if you have:

• tremors, shaking, restless movement, problems with balance;
• uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
• trouble swallowing;
• fast or pounding heartbeats;
• a light-headed feeling, like you might pass out; or
• severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats.

Common side effects of tetrabenazine may include:

• drowsiness, tiredness;
• depressed mood;
• nausea; or
• feeling anxious, agitated, or restless.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

When first prescribed tetrabenazine should be increased slowly over several weeks to identify a dose that reduces chorea and is tolerated.

Usual Tetrabenazine Adult Dose for Huntington Disease:

Initial dose: First week: 12.5 mg orally daily Second week: 12.5 mg orally 2 times daily Maintenance dose: Increase by 12.5 mg orally weekly to tolerated dose that reduces chorea. Doses of 37.5mg to 50 mg daily should be administered in 3 divided doses. Maximum recommended single dose: 25 mg

Comments: Determine CYP450 2D6 metabolizer status in patients who require doses of greater than 50 mg per day.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

If you miss your doses for more than 5 days in a row, ask your doctor before you start taking tetrabenazine again.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Tetrabenazine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Drinking alcohol with this medicine can cause side effects.

Other drugs may interact with tetrabenazine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

It is important to tell your doctor if you take:

• reserpine
• monoamine oxidase inhibitors (MAOIs);
• alcohol or other sedating drugs;
• Drugs that cause QTc prolongation 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;
• neuroleptic drugs (e.g., chlorpromazine, haloperidol, olanzapine, risperidone, thioridazine, ziprasidone);
• strong CYP2D6 inhibitors;
• deutetrabenazine or valbenazine.

For more information on interactions with tetrabenazine click on the link below.

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

Xenazine Brand

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

Manufactured for: Lundbeck Deerfield, IL 60015 USA.

Xenazine is a trademark of Bausch Health Companies Inc. or its affiliates.

Active ingredient: tetrabenazine

Inactive Ingredients:

• Xenazine 12.5 mg tablet: lactose, magnesium stearate, maize starch, and talc.
• Xenazine 25mg tablet: lactose, magnesium stearate, maize starch, talc, and yellow iron oxide. as an inactive ingredient.