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Xenazine Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Xenazine (tetrabenazine) is used to treat Huntington's chorea (uncontrolled muscle movements). It reduces the amount of certain chemicals in the body that are overly active in people with Huntington's disease. Common side effects include insomnia, mild drowsiness, tired feeling, nausea, or breast swelling or discharge.

The starting dose of Xenazine is 12.5 mg per day given once in the morning. After one week, the dose is increased to 25 mg per day given as 12.5 mg twice a day. Xenazine may interact with arsenic trioxide, droperidol, celecoxib, cimetidine, darifenacin, ropinirole, terbinafine, ADHD medications, antibiotics, antidepressants, anti-malaria medications, cancer medications, heart rhythm medications, HIV or AIDS medicines, medicine to treat or prevent nausea and vomiting, medicine to treat psychiatric disorders, migraine headache medicines, or narcotics. Tell your doctor all medications you use. During pregnancy, Xenazine should be taken only if prescribed. It is unknown if this drug passes into breast milk or if it could harm a nursing baby. Consult your doctor before breast-feeding.

Our Xenazine (tetrabenazine) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Xenazine in Detail - Patient Information: Side Effects

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

Stop using tetrabenazine and call your doctor at once if you have a serious side effect such as:

  • extreme drowsiness;
  • mood or behavior changes, thoughts about suicide or hurting yourself;
  • feeling restless, agitated, or hyperactive (mentally or physically);
  • tremor (uncontrolled shaking), restless muscle movements in your eyes, tongue, jaw, or neck;
  • trouble swallowing;
  • problems with balance;
  • dizziness, fainting, fast or pounding heartbeat;
  • very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, feeling like you might pass out;
  • muscle pain, tenderness, or weakness with fever or flu symptoms and dark colored urine; or
  • urinating less than usual or not at all, swelling, weight gain, feeling short of breath.

Less serious side effects may include:

  • sleep problems (insomnia);
  • feeling anxious or irritable;
  • mild drowsiness, tired feeling;
  • mild nausea;
  • breast swelling or discharge; or
  • cold symptoms such as stuffy nose, sneezing, sore throat.

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.

Read the entire detailed patient monograph for Xenazine (Tetrabenazine Tablets)

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Xenazine FDA Prescribing Information: Side Effects
(Adverse Reactions)


The following risks are discussed in greater detail in other sections of the labeling:

Commonly Observed Adverse Reactions in Controlled Clinical Trials

The most common adverse reactions from Table 1 occurring in over 10% of XENAZINE-treated patients, and at least 5% greater than placebo, were sedation/somnolence (31%), fatigue (22%), insomnia (22%), depression (19%), akathisia (19%), and nausea (13%).

Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

During its development, XENAZINE was administered to 773 unique subjects and patients. The conditions and duration of exposure to XENAZINE varied greatly, and included single and multiple dose clinical pharmacology studies in healthy volunteers (n=259) and open-label (n=529) and double-blind studies (n=84) in patients.

In a randomized, 12-week, placebo-controlled clinical trial of HD subjects, adverse reactions (ARs) were more common in the XENAZINE group than in the placebo group. Forty-nine of 54 (91%) patients who received XENAZINE experienced one or more ARs at any time during the study. The ARs most commonly reported (over 10%, and at least 5% greater than placebo) were sedation/somnolence (31% vs. 3% on placebo), fatigue (22% vs. 13% on placebo), insomnia (22% vs. 0% on placebo), depression (19% vs. 0% on placebo), akathisia (19% vs. 0% on placebo), and nausea (13% vs. 7% on placebo).

Adverse Reactions Occurring in ≥ 4% Patients

The number and percentage of the most commonly reported AEs that occurred at any time during the study in ≥ 4% of XENAZINE-treated patients, and with a greater frequency than in placebo-treated patients, are presented in Table 1 in decreasing order of frequency within body systems for the XENAZINE group.

Table 1: Treatment Emergent Adverse Reactions in Patients Treated with XENAZINE and with a Greater Frequency than Placebo in the 12-Week, Double-Blind, Placebo- Controlled Trial of XENAZINE

Body System AE Term XENAZINE
n = 54
n (%)
n = 30
n (%)
PSYCHIATRIC DISORDERS Sedation/ somnolence 17 (31%) 1 (3%)
Insomnia 12 (22%) -
Depression 10 (19%) -
Anxiety/anxiety aggravated 8 (15%) 1 (3%)
Irritability 5 (9%) 1 (3%)
Appetite decreased 2 (4%) -
Obsessive reaction 2 (4%) -
Akathisia 10 (19%) -
Balance difficulty 5 (9%) -
CENTRAL & PERIPHERAL Parkinsonism/ bradykinesia 5 (9%) -
NERVOUS SYSTEM Dizziness 2 (4%) -
Dysarthria 2 (4%) -
Gait unsteady 2 (4%) -
Headache 2 (4%) 1 (3%)
GASTROINTESTINAL Nausea 7 (13%) 2 (7%)
SYSTEM DISORDERS Vomiting 3 (6%) 1 (3%)
Fatigue 12 (22%) 4 (13%)
BODY AS A WHOLE - Fall 8 (15%) 4 (13%)
GENERAL Laceration (head) 3 (6%) -
Ecchymosis 3 (6%) -
RESPIRATORY SYSTEM Upper respiratory tract infection 6 (11%) 2 (7%)
DISORDERS Shortness of breath 2 (4%) -
Bronchitis 2 (4%) -

Dose escalation was discontinued or dosage of study drug was reduced because of one or more ARs in 28 of 54 (52%) patients randomized to XENAZINE. These ARs consisted of sedation (15), akathisia (7), parkinsonism (4), depression (3), anxiety (2), fatigue (1) and diarrhea (1).

Some patients had more than one AR and are, therefore, counted more than once.

Adverse Reactions Due to Extrapyramidal Symptoms (EPS)

The following table describes the incidence of events considered to be extrapyramidal adverse reactions.

Table 2: Treatment Emergent EPS in Patients Treated with XENAZINE Occurring with a Greater Frequency than Placebo in the 12-Week, Double-Blind, Placebo-Controlled Trial of XENAZINE

Event Patients (%) reporting event
n = 54
n = 30
Akathisia1 10 (19%) 0
Extrapyramidal event2 8 (15%) 0
Any extrapyramidal event 18 (33%) 0
1Patients with the following adverse event preferred terms were counted in this category: akathisia, hyperkinesia, restlessness.
2Patients with the following adverse event preferred terms were counted in this category: bradykinesia, parkinsonism, extrapyramidal disorder, hypertonia.

Patients may have had events in more than one category.

Laboratory Tests

No clinically significant changes in laboratory parameters were reported in clinical trials with XENAZINE. In controlled clinical trials, XENAZINE caused a small mean increase in alanine Patients (%) reporting event aminotransferase (ALT) and aspartate aminotransferase (AST), laboratory values as compared to placebo.

Vital Signs

In controlled clinical trials, XENAZINE did not affect blood pressure, pulse, and body weight.

Orthostatic blood pressure was not consistently measured in the XENAZINE clinical trials.

Read the entire FDA prescribing information for Xenazine (Tetrabenazine Tablets)


Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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