Xenazine (Tetrabenazine) - Oral

What Is Xenazine?

Xenazine (tetrabenazine) is a medication option used to treat abnormal and extra muscle movements in people with Huntington's disease (HD).

Xenazine is a vesicular monoamine transporter 2 (VMAT2) inhibitor. It's thought to work by preventing VMAT2 from moving monoamines (naturally occurring brain chemicals) into vesicles. Neurons (nerve cells) make the monoamines—like dopamine—and store the brain chemicals in vesicles. Blocking VMAT2 eventually leads to decreasing amounts of monoamines.

Xenazine is available as a prescription tablet.

What Is Xenazine Used For?

Xenazine is used to treat abnormal and extra muscle movements in Huntington's disease (HD).

HD is a medical condition that runs in families. In HD, there is a loss of brain and muscle function that worsens over time. People with HD tend to experience chorea (uncontrolled muscle movements). Symptoms may also include changes in mood, behavior, and ways of thinking.

HD is estimated to affect between 300 to 3,000 people in the United States (U.S.). Most people with HD typically begin to have symptoms in their 30s and 40s. There are a smaller number of people who experience an early onset of symptoms as children.

How to Take Xenazine

In general, Xenazine is taken by mouth with or without food. You will usually start taking Xenazine once daily. As your healthcare provider slowly increases your dosage, however, you will likely take Xenazine two to three times daily.

Storage

When you receive Xenazine from the pharmacy, store it at 77 degrees Fahrenheit (F)—with a short-term safety storage range of 59 degrees to 86 degrees F.

To be safe, you may also place Xenazine in a locked cabinet or closet to keep your medication out of the reach of children and pets.

If you plan to travel with Xenazine, get familiar with your final destination's regulations. Checking with the U.S. embassy or consulate might be a helpful resource. In general, however, be sure to make a copy of your Xenazine prescription. If possible, keep your medication in its original container from your pharmacy with your name on the label. If you have any questions about traveling with your medicine, be sure to ask your pharmacist or healthcare provider.

You can also ask your pharmacist or healthcare provider about the best ways to dispose of your medications. The FDA's website is a potentially helpful resource to know where and how to discard all unused and expired drugs. You can also find disposal boxes in your area.

Off-Label Uses

Experts may recommend using Xenazine to treat tardive dyskinesia (TD). TD is a condition of abnormal muscle movements in the face, neck, arms, and legs. TD is a serious side effect of antipsychotic medications—like haloperidol.

What are the Side Effects of Xenazine?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects with Xenazine may include:

• Anxiety
• Nausea
• Restlessness
• Sleepiness or drowsiness
• Sleeping difficulties
• Tiredness or low energy
  

Severe Side Effects

Get medical help right away if you develop any of the following serious side effects. Call 911 if your symptoms feel life-threatening.

Serious side effects of Xenazine and their symptoms include:

• Severe allergic reaction: If you have a severe allergic reaction to Xenazine, you may experience symptoms of itchiness, rash, and swelling.
• Abnormal heart rhythm: Xenazine may raise your risk of an abnormal heart rhythm. The likelihood of this increases if Xenazine is combined with other medications—like the levofloxacinfluoroquinolone antibiotic—that also have the same risk.
• Depression and suicide risk: Xenazine raises your risk of depression and suicide. Keep an eye out for changes in mood and behavior.
• Excess Xenazine in melanin-containing tissues: Melanin is a dark-colored substance that can be found in the following tissues: skin, hair, and eyes. Xenazine may build up in these tissues over time. Excess Xenazine in these tissues may lead to toxicity or injury.
• High prolactin levels: Xenazine may lead to high prolactin hormone levels. High amounts of prolactin are typically linked to the following symptoms: missing menstrual periods, enlarged breasts, lactation (milky substance leaking from the nipples), and erectile dysfunction (ED).
• Low blood pressure: Xenazine is linked to dangerously low blood pressure. If you have low blood pressure, you may feel dizzy or faint.
• Neuroleptic malignant syndrome: Neuroleptic malignant syndrome (NMS) is a rare and life-threatening reaction to certain medications—like Xenazine. Symptoms may include muscle stiffness, blood pressure changes, high fever, excessive sweating, and a lot of salivae (spit). You may also experience changes in mood or behavior.
• Restlessness: Restless is a common side effect of Xenazine. At high doses of Xenazine, however, this side effect can become excessive and severe. You may also experience agitation and Parkinson-like symptoms.
• Sleepiness and drowsiness: Although sleepiness and drowsiness are common side effects of Xenazine, they can become excessive and severe.

Long-Term Side Effects

Possible long-term side effects of Xenazine may include:

• Anxiety
• Depression
• Drowsiness
• Parkinson-like symptoms
• Restlessness
• Sleeping difficulties

Long-term use of Xenazine may lead to a build-up of this medication in melanin-containing tissues, such as the eyes. Excess Xenazine in these tissues may lead to toxicity and injury.

Dosage: How Much Xenazine Should I Take?

Modifications

The following modifications (changes) should be kept in mind when using Xenazine:

Severe allergic reaction: Avoid using Xenazine if you have a known allergy to it or any of its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: In animal studies in rats, Xenazine was linked to negative effects on the fetus. We don't know enough about the safety and effectiveness of Xenazine in pregnant people and on their unborn fetuses. Discuss with your healthcare provider if you plan to become pregnant or are pregnant. Your healthcare provider can help you weigh the benefits and risks of taking Xenazine during your pregnancy.

Breastfeeding: We don't know enough of about the safety and effects of Xenazine in human breastmilk and nursing babies. Talk with your healthcare provider if you plan to breastfeed. Your healthcare provider can help you weigh the benefits and harms of taking Xenazine while nursing. They can also discuss the different ways available to feed your baby.

Adults over 65: Clinical studies haven't included a large enough number of people in this age group to see whether they respond differently from younger adults.

Children: There is limited safety and effectiveness information about Xenazine in children.

Liver problems: If you have any degree of liver impairment, Xenazine isn't recommended for you.

Poor CYP2D6 metabolizers: CYP2D6 is a protein in the liver. It's responsible for breaking down medications—like Xenazine. Some people are poor CYP2D6 metabolizers (PMs). If you're a PM, this means that your CYP2D6 proteins don't work as quickly as the general public. As a result, you're at risk of more side effects from the build-up of Xenazine in your body. Therefore, your healthcare provider will likely limit your maximum total daily dose (TDD) to 50 milligrams (mg). They may also recommend that you don't take more than 25 milligrams at any time. So your highest Xenazine dosage, for example, might be 25 milligrams twice daily.

Extensive or intermediate CYP2D6 metabolizers: Some people are extensive (EM) or intermediate (IM) CYP2D6 metabolizers. If you're an EM or IM, your CYP2D6 proteins work more quickly than PM. Therefore, your healthcare provider may recommend a maximum TDD of up to 100 milligrams, but you may only take up to 37.5 milligrams at any time. For example, your healthcare provider may recommend the following Xenazine dosage: 25 milligrams in the morning, 37.5 milligrams in the afternoon, and 37.5 milligrams in the evening.

Missed Dose

If you accidentally forgot your Xenazine dose, take it as soon as you remember. If it's already close to your next scheduled dose, however, then skip the missed dose and take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

If you miss more than five days of Xenazine doses, talk with your healthcare provider before taking Xenazine again. Your healthcare provider may need to restart you at a lower Xenazine dose.

Try to find ways that work for you to help yourself remember to routinely take your medication. If you miss just one Xenazine dose, your uncontrolled muscle movements may come back or worsen within 15 to 18 hours of your last dose.

Overdose: What Happens If I Take Too Much Xenazine?

There are reports of overdose with Xenazine—with a dosage range of 100 to 1000 milligrams (mg). Symptoms of a suspected overdose may include:

• Abnormal and uncontrollable muscle movements
• Confusion
• Diarrhea
• Eye muscle spasms that cause the eyeball(s) to be fixed in one position—typically upwards
• Low blood pressure
• Nausea and vomiting
• Skin redness
• Sleepiness and drowsiness
• Sweating
• Tremors

If you think that you're experiencing an overdose or life-threatening symptoms, seek immediate medical attention.

Precautions

What Are Reasons I Shouldn’t Take Xenazine?

Before taking Xenazine, talk with your healthcare provider if any of the following applies to you:

• Severe allergic reaction: If you have a severe allergic reaction to Xenazine or any of its components (ingredients), then Xenazine isn't a viable option for you.
• Depression and suicide: Xenazine may raise the risk of depression and suicide. If you're having undertreated depression or actively experiencing a suicidal crisis, then taking Xenazine isn't recommended.
• Pregnancy: In humans, there is not enough information on the effects and safety of Xenazine on the unborn fetus. Discuss with your healthcare provider about the benefits and risks of taking Xenazine during your pregnancy.
• Breastfeeding: In humans, there is limited data on the effects and safety of Xenazine on nursing babies. Talk with your healthcare provider about the benefits and harms of taking Xenazine while nursing.
• Adults over 65: There isn't enough data to assess the differences in effectiveness and safety of Xenazine between older and younger adults.
• Children: We don't have enough information about the effectiveness and safety of Xenazine in children.
• Liver problems: Xenazine is broken down by proteins in the liver. If you have any degree of liver impairment, Xenazine isn't recommended for you.
• Monoamine oxidase inhibitor (MAOI) use: If you've taken an MAOI—like selegiline for depression or Parkinson's disease (PD)—within the last 14 days, don't take Xenazine.
• Reserpine use: If you've taken reserpine within the previous 20 days, avoid Xenazine. Reserpine is a treatment option for high blood pressure or schizophrenia.
• Austedo and Ingrezza: Austedo (deutetrabenazine) and Ingrezza (valbenazine) are used for muscle movement conditions. Like Xenazine, they are also VMAT2 inhibitors. Avoid combining Xenazine with another VMAT2 inhibitor.

What Other Medications Interact With Xenazine?

As previously mentioned, avoid combining Xenazine with other VMAT2 inhibitors—like Austedo and Ingrezza. You should also avoid Xenazine with MAOIs within the previous 14 days and reserpine within the last 20 days.

The following are additional medications to use with caution when taking Xenazine:

• Abnormal heart rhythm medications: Xenazine may raise your risk of an abnormal heart rhythm. An irregular heart rhythm is more likely when Xenazine is combined with other medications—like the levofloxacin fluoroquinolone antibiotic—that have the same side effect.
• Alcohol and other sleep-inducing medications: Combining Xenazine with alcohol or other sleep-inducing medications may worsen the side effects of drowsiness and sleepiness.
• Antipsychotic medications: Taking Xenazine with antipsychotic medications—like haloperidol—raises your risk of severe side effects like restlessness, Parkinson-like symptoms (ex., tremors), and neuroleptic malignant syndrome (NMS) (a life-threatening condition with fever and changes in mental status).
• CYP2D6 inhibitors: CYP2D6 is a protein in the liver responsible for breaking down medications—like Xenazine. If you take a CYP2D6 inhibitor—like Prozac (fluoxetine), your CYP2D6 will not work either. As a result, you may have a build-up of Xenazine in your body—with a higher likelihood of side effects. Therefore, your healthcare provider may need to lower your Xenazine dosage.
  

Talk with your pharmacist or healthcare provider for more detailed information about medication interactions with Xenazine.

And be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter, nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

A few medication options are used for Huntington's disease (HD) chorea (abnormal and uncontrolled muscle movements). Of all the available options, experts tend to recommend Xenazine as the first-choice option for HD chorea.

Xenazine is a vesicle monoamine transporter 2 (VMAT2) inhibitor that affects the amounts and activities of various brain chemicals—especially dopamine. So, other similar medications include another VMAT2 inhibitor (e.g., Austedo) and second-generation antipsychotics (e.g., clozapine, olanzapine, etc.).

Experts recommend Austedo as a potential alternative to Xenazine. Both medications are VMAT2 inhibitors, but Austedo isn't available as a generic version yet. Therefore, Austedo might be more costly than Xenazine.

Many second-generation antipsychotics, on the other hand, are available as generic products. For HD chorea, experts may recommend second-generation antipsychotics as go-to options—especially if an individual with HD chorea also has a behavioral or mental health condition.

Treating HD chorea is preferred over multiple medications to limit side effects. Furthermore, combining multiple VMAT2 inhibitors should be avoided.

How Can I Stay Healthy While Taking Xenazine?

If you're taking Xenazine, chances are Huntington's disease (HD) has been negatively affecting your quality of life. You may have tried different approaches or treatments. While living with HD does have its challenges, there are ways to help improve your quality of life. Refer below for some general tips to support your health:

• Take HD-related medications as recommended by your healthcare provider.
• Consider support groups or working with a mental health professional to help you find coping strategies to change the way you think, feel, react, or respond to living with HD.
• Consider visiting the Huntington's Disease Society of America (HDSA) website. This organization offers support for people with HD and their loved ones. HDSA also provides educational tools. It also coordinates support groups on a national level.
• Find ways to manage your stress.
• Have a regular routine.
• Regularly exercise.
• Use memory aids, reminders, cues, or prompts to help you stay organized and complete tasks.
• Participate in enjoyable activities.
• Avoid alcohol and marijuana. Alcohol and marijuana can act as depressants. They may make you more dizzy or drowsy.
• Avoid tobacco products.