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Prescribing Xenazine Medication Assistance Program

HSG Results


Xenazine significantly decreased Total Chorea Scores from baseline:1,3

chart

  • 91% of Xenazine patients and 97% of placebo patients completed the study following titration and dose optimization.1
  • Xenazine patients had an estimated decrease of 5.0 units during maintenance therapy compared to a decrease of 1.5 units in placebo patients.1
  • At the conclusion of the trial (week 12) when patients were at their maintenance dose, there was no significant difference in adverse events between Xenazine and placebo patients with regard to specific adverse events that had not been reported at baseline.3
    • The mean daily dose in this study was 75 mg.2
chart
  • Xenazine should be titrated up slowly for a dose that is appropriate for each patient.1
  • Before receiving a dose greater than 50 mg, the patient's CYP2D6 metabolizer status should be determined.1

Xenazine Significantly Improved CGI Global Improvement Scores from Baseline3

chart


69% of Xenazine-treated patients' CGI scores significantly improved.3

On the Clinical Global Impression (CGI) scale, 69% of patients improved with Xenazine compared with 24% of patients treated with placebo.3

HSG Trial Exploratory Outcomes:3

  • Xenazine had no significant impact on the UHDRS Total Motor Scores.
  • Xenazine had an adverse impact on the UHDRS Functional Checklist, with the Xenazine group worsening by 0.8 units compared with the placebo group improving by 0.4 units (P = 0.02).
  • Xenazine had no significant impact on UHDRS gait assessment, UHDRS parkinsonism score, or any other exploratory outcome measures (Total Functional Capacity, Functional Impact Scale, Independence Scale).
  • Xenazine had no significant impact on the Barnes Akathisia Scale, UHDRS Behavioral Assessment, Unified Parkinson's Disease Rating Scale (UPDRS) swallowing, or UPDRS speech items.
  • Xenazine had an adverse impact on Stroop word reading but not on other UHDRS measures of cognitive function.
  • Xenazine and placebo had an improvement on the 17-item HAM-D, but results favored placebo over Xenazine.

Withdrawal Study:1

A second controlled study was performed in patients who had been treated with open-label Xenazine for at least 2 months. (Mean duration of treatment was 2 years.) They were randomized to continuation of Xenazine at the same dose (n = 12) or to placebo (n = 6) for 3 days, at which time their chorea scores were compared. Although the comparison did not reach statistical significance (P = 0.1), the estimate of the treatment effect was similar to that seen in the HSG Trial (about 3.5 units).

Sources:

  • Xenazine [package insert]. Deerfield, IL: Lundbeck Inc; 2009.
  • Data on file, Biovail Corporation.
  • Huntington Study Group. Tetrabenazine as antichorea therapy in Huntington disease: a randomized controlled trial. Neurology. 2006; 66(3):366-372.


XENAZINE® (tetrabenazine) Tablets

Indications and Usage:

Xenazine is indicated for the treatment of chorea associated with Huntington’s disease.

Important Safety Information:

DEPRESSION AND SUICIDALITY

XENAZINE can increase the risk of depression and suicidal thoughts and behavior (suicidality) in patients with Huntington’s disease. Anyone considering the use of XENAZINE must balance the risks of depression and suicidality with the clinical need for control of choreiform movements. Close observation of patients for the emergence or worsening of depression, suicidality, or unusual changes in behavior should accompany therapy. Patients, their caregivers, and families should be informed of the risk of depression and suicidality and should be instructed to report behaviors of concern promptly to the treating physician.

Particular caution should be exercised in treating patients with a history of depression or prior suicide attempts or ideation, which are increased in frequency in Huntington’s disease. XENAZINE is contraindicated in patients who are actively suicidal, and in patients with untreated or inadequately treated depression.

Xenazine is also contraindicated in patients who have impaired hepatic function or are taking monoamine oxidase inhibitors or reserpine. At least 20 days should elapse after stopping reserpine before starting Xenazine.

The need for therapy should be evaluated on an ongoing basis with the patient’s doctor. Xenazine should be titrated slowly over several weeks for a dose that is appropriate for each patient. Before a dose greater than 50 mg is administered, the patient’s CYP2D6 metabolizer status should be determined.

Neuroleptic malignant syndrome (NMS), akathisia, agitation, parkinsonism, dysphagia, and QT prolongation–related arrhythmias have been reported with use of Xenazine. Xenazine should not be used in combination with drugs known to prolong QTc (which in certain circumstances can lead to torsades de pointes and/or sudden death), in patients with congenital long QT syndrome, or in patients with a history of cardiac arrhythmias. A potentially irreversible syndrome of involuntary, dyskinetic movements called tardive dyskinesia (TD) may develop in patients treated with neuroleptic drugs. If signs and symptoms of TD appear in a patient treated with Xenazine, drug discontinuation should be considered. Adverse reactions associated with Xenazine, such as QTc prolongation, NMS, and extrapyramidal disorders, may be exaggerated by concomitant use of dopamine antagonists.

Xenazine elevates serum prolactin concentrations. Xenazine may induce sedation and somnolence (sleepiness or drowsiness) and may impair the ability to drive or operate dangerous machinery.

Some adverse events such as depression, fatigue, insomnia, sedation/somnolence, parkinsonism, and akathisia may be dose-dependent. If the adverse effect does not resolve or decrease, consideration should be given to lowering or discontinuing Xenazine. The most commonly reported adverse events with Xenazine compared to placebo were sedation/somnolence (31% vs 3%), fatigue (22% vs 13%), insomnia (22% vs 0%), depression (19% vs 0%), akathisia (19% vs 0%), anxiety (15% vs 3%), and nausea (13% vs 7%).

For more information, please see Full Prescribing Information, including Boxed Warning.

®Xenazine is a registered trademark of Biovail Laboratories International (Barbados) S.R.L.

©2009 Lundbeck Inc., Deerfield IL 60015. All rights reserved.

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