Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2022 Publisher: Bausch Health Ireland Limited, 3013 Lake Drive, Citywest Business Campus, Dublin 24, D24PPT3, Ireland
Movement disorders associated with organic central nervous system conditions, e.g., Huntington’s chorea, hemiballismus and senile chorea.
Xenazine 25 is also indicated for the treatment of moderate to severe tardive dyskinesia, which is disabling and/or socially embarrassing. The condition should be persistent despite withdrawal of antipsychotic therapy, or in cases where withdrawal of antipsychotic medication is not a realistic option; also where the condition persists despite reduction in dosage of antipsychotic medication or switching to atypical antipsychotic medication.
The tablets are for oral administration.
Dosing of tetrabenazine involves careful titration of therapy to determine an individualised dose for each patient. When first prescribed, tetrabenazine therapy should be titrated slowly over several weeks to allow the identification of a dose for chronic use that reduces chorea and is well tolerated.
Dosage and administration are variable and only a guide is given. Starting doses should be 12.5 mg to 25 mg per day and should be titrated up slowly every 4 to 7 days to allow identification of dose that is efficacious and well tolerated. After titration is initiated, the total daily dose should be given in two to three divided doses. Titration can be up to 200 mg per day or dose-limiting adverse events, whichever happens first. If the adverse event does not resolve, after dose reduction, consideration should be given to withdrawing tetrabenazine treatment.
If there is no improvement at the maximum dose in seven days, it is unlikely that the compound will be of benefit to the patient, either by increasing the dose or by extending the duration of treatment.
Discontinuation of tetrabenazine is associated with the return of chorea (without significant worsening compared to baseline). Other adverse reactions to sudden treatment withdrawal are possible but unlikely and generally mild.
Following treatment interruption of greater than 5 days or a treatment interruption occurring due to a change in the patient’s medical condition or concomitant medications, tetrabenazine therapy should be retitrated when resumed. The dose should be initiated at 12.5 mg twice a day, wait 7 days then titrate up by 12.5 mg per day.
If adverse events such as akathisia, restlessness, parkinsonism, depression, insomnia, anxiety, or intolerable sedation occur, titration should be stopped and the dose should be reduced.
Recommended starting dose of 12.5 mg a day subsequently titrated according to response. Medication should be discontinued if there is no clear benefit or if the side-effects cannot be tolerated.
For any indication, if adverse events such as akathisia, restlessness, parkinsonism, depression, insomnia, anxiety, or intolerable sedation occur, titration should be stopped and the dose should be reduced.
No specific studies have been performed in the elderly.
The safety and efficacy of tetrabenazine in children have not been established.
A study in hepatically impaired subjects has shown that there is a markedly decreased metabolism of tetrabenazine to its metabolites with a higher mean Cmax in hepatically impaired subjects in comparison with healthy subjects. The elimination half life of tetrabenazine and its metabolites in subjects with hepatic impairment was also prolonged.
Increased exposure to other circulating metabolites and the contribution of tetrabenazine or those metabolites to safety and efficacy are unknown. Therefore, tetrabenazine is contraindicated in hepatic impairment, regardless of the severity of the impairment (see section 5.2).
The use of tetrabenazine in patients with renal insufficiency has not been studied.
Symptoms associated with overdoses of tetrabenazine may include: acute dystonia, oculogyric crisis, nausea, vomiting, diarrhoea, sweating, hypotension, hypothermia, confusion, hallucinations, sedation, rubor and tremor.
Treatment should consist of those general measures employed in the management of overdosage with any CNS-active drug. General supportive and symptomatic measures are recommended. Cardiac rhythm and vital signs should be monitored. In managing overdosage, the possibility of multiple drug involvement should always be considered. The physician should consider contacting a poison control centre on the treatment of any overdose.
5 years.
Do not store above 30°C.
White HDPE bottle with a white HDPE cap. Pack size of 112 tablets.
No special requirements.
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