Xenazine (Generic)

Tetrabenazine is used to decrease the uncontrollable movements (chorea) caused by Huntington's disease. However, it is not a cure for the disease. Reducing the chorea will help you take part in more of your normal daily activities. This medication is thought to work by decreasing the amount of certain natural substances in the brain (monoamines such as dopamine, serotonin, and norepinephrine), which are involved with nerve and muscle function. Tetrabenazine belongs to a class of drugs called monoamine depletors.

Read the Medication Guide provided by your pharmacist before you start using tetrabenazine and each time you get a refill. If you have any questions, consult your doctor or pharmacist.

Take this medication by mouth with or without food, usually once a day in the morning when you first start treatment or as directed by your doctor. Your doctor may gradually increase your dose to 2 or 3 times a day over several weeks. A slow increase in your dose will help your doctor find the best dose for you while keeping side effects as low as possible.

The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Take this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

If you stop taking this drug for several days, then start taking it again, you may need to slowly increase your dose until you reach the regular dose you had been taking. Follow your doctor's directions on how to restart treatment.

Tell your doctor if your uncontrolled movements do not improve or if they worsen.

See also Warning section.

Drowsiness, trouble sleeping, tiredness, dizziness, nausea, and vomiting may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Your doctor may need to adjust your dose to reduce these side effects.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Sometimes tetrabenazine can cause side effects that are similar to the symptoms of worsening Huntington's disease. Your doctor may need to adjust your dose to see if these side effects are due to the drug or to the disease. Tell your doctor right away if any of these serious side effects occur: mental/mood changes (such as new/worsening depression, suicidal thoughts/attempts, problems with thinking), Parkinson's disease symptoms (such as shaking/tremors, slowed movement, loss of balance), trouble swallowing, restlessness.

Tell your doctor right away if any of these unlikely but serious side effects occur: signs of increased prolactin hormone (such as enlarged breasts, abnormal breast milk production, decreased sexual ability, a change in menstrual cycle).

Seek immediate medical attention if you have any of these rare but serious (possibly fatal) side effects: fast/irregular heartbeat, severe dizziness, fainting.

This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, muscle stiffness/pain/tenderness/weakness, severe tiredness, severe confusion, sweating, fast/irregular heartbeat, dark urine, signs of kidney problems (such as change in the amount of urine).

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking tetrabenazine, tell your doctor or pharmacist if you are allergic to it; or to deutetrabenazine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: liver problems, depression that is untreated or not responding to treatment, thoughts of suicide.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: breast cancer.

Tetrabenazine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using tetrabenazine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using tetrabenazine safely.

This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is not known whether this drug passes into breast milk. Consult your doctor before breast-feeding.

Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are: valbenazine.

Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Do not take any MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before and after treatment with this medication. Ask your doctor when to start or stop taking this medication.

Tetrabenazine is very similar to deutetrabenazine. Do not use medications containing deutetrabenazine while using tetrabenazine.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: muscle stiffness/pain, fixed upward position of the eyeballs, sweating, dizziness, severe drowsiness.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Do not share this medication with others.

Laboratory and/or medical tests may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.