Tetrabenazine

Tetrabenazine may increase the risk of depression or suicidal thoughts (thinking about harming or killing yourself or planning or trying to do so) in people with Huntington's disease (an inherited disease that causes the progressive breakdown of nerve cells in the brain). Tell your doctor if you have or have ever had depression and if you have or have ever had thoughts about harming or killing yourself. Your doctor will probably tell you not to take tetrabenazine. You, your family, or caregiver should call your doctor right away if you experience any of the following symptoms: new or worsening depression, thoughts about harming or killing yourself or planning or trying to do so, extreme worry, agitation, difficulty falling asleep or staying asleep, aggressive or hostile behavior, irritability, acting without thinking, severe restlessness, anxiety, changes in body weight, loss of interest in social interactions, difficulty paying attention, or any other unusual changes in behavior. Be sure that your family or caregiver checks on you regularly and knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.

Keep all appointments with your doctor. Your doctor will probably want to talk with you about your mental health while you are taking this medication.

Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with tetrabenazine and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (https://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer's website to obtain the Medication Guide.

Tetrabenazine is used to treat chorea (sudden movements that you cannot control) caused by Huntington's disease (an inherited disease that causes the progressive breakdown of nerve cells in the brain). Tetrabenazine is in a class of medications called vesicular monoamine transporter 2 (VMAT2) inhibitors. It works by changing the activity of certain natural substances in the brain that affect nerves and muscles.

Tetrabenazine comes as a tablet to take by mouth with or without food. It is usually taken once a day at first, then increased to twice a day one week later, and then increased to three times a day one week after that. Take tetrabenazine at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tetrabenazine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of tetrabenazine and gradually increase or decrease your dose, not more than once every week, depending on how well the medication works for you and the side effects you experience. Be sure to tell your doctor how you are feeling so that your doctor can prescribe the right amount of medication to treat your condition with the lowest risk of side effects.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking tetrabenazine,

• tell your doctor and pharmacist if you are allergic to tetrabenazine, any other medications, or any of the ingredients in tetrabenazine tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor or pharmacist if you are taking the following medications or have stopped taking them in within the past two weeks: reserpine, deutetrabenazine (Austedo), valbenazine (Ingrezza), or a monoamine oxidase (MAO) inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate).
• some medications should not be taken with tetrabenazine. Other medications may cause dosing changes or extra monitoring when taken with tetrabenazine. Make sure you have discussed any medications you are currently taking or plan to take before starting tetrabenazine with your doctor and pharmacist. Before starting, stopping, or changing any medications while taking tetrabenazine, please get the advice of your doctor or pharmacist.
• tell your doctor if you have liver disease. Your doctor will probably tell you not to take tetrabenazine.
• tell your doctor if you have recently had a heart attack or if you have or have ever had long QT syndrome (condition that increases the risk of developing an irregular heartbeat that may cause fainting or sudden death), another type of irregular heartbeat or heart rhythm problem, heart failure, or heart disease. Also tell your doctor if you have low blood levels of magnesium or potassium in your blood or breast cancer.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking tetrabenazine, call your doctor.
• you should know that tetrabenazine may make you drowsy or cause tiredness. Do not drive a car or operate machinery until you know how this medication affects you.
• you should know that alcohol can add to the drowsiness caused by this medication. Do not drink alcohol while taking tetrabenazine.
• you should know that tetrabenazine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.

Unless your doctor tells you otherwise, continue your normal diet.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

If you miss taking tetrabenazine for more than 5 days, talk to your doctor before starting to take it again. You will probably have to restart taking it at a lower dose.

Tetrabenazine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• diarrhea
• vomiting
• decreased appetite
• headache
• pain or burning upon urination
• bruising
• difficulty speaking or being understood

Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING section, stop taking tetrabenazine and call your doctor immediately:

• fever, sweating, confusion, fast or irregular heartbeat, and severe muscle stiffness
• difficulty moving, or keeping your balance
• muscle stiffness
• irregular heartbeat
• shortness of breath
• restlessness

Tetrabenazine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location — one that is up and away and out of their sight and reach. https://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (https://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• twisting or jerking movements
• rapid eye movement
• nausea
• vomiting
• sweating
• extreme tiredness
• confusion
• diarrhea
• hallucinations (seeing thing or hearing voices that do not exist)
• redness of the skin
• uncontrollable shaking

Keep all appointments with the laboratory. Your doctor may order certain lab tests to check your body's response to tetrabenazine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

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