Source: Health Products Regulatory Authority (IE) Revision Year: 2019 Publisher: Bausch Health Ireland Limited, 3013 Lake Drive, Citywest Business Campus, Dublin 24, Ireland
In the control of disorders of movement associated with organic disease of the central nervous system, such as Huntington’s chorea, hemiballismus and senile chorea.
Proper 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 a 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. For short-term treatment interruption of less than 5 days, treatment can be resumed at the previous maintenance dose without titration.
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 patients with hepatic impairment, Child Pugh 5 to 9 (see section 5.2).
The use of tetrabenazine in patients with renal insufficiency has not been studied.
The tablets are for oral administration.
Symptoms associated with overdoses of tetrabenazine may include acute dystonia, oculogyric crisis, nausea, vomiting, diarrhoea, sweating, hypotension, confusion, hallucinations, hypothermia, 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.
Five years.
Do not store above 30°C.
A white HDPE bottle containing 112 tablets with a white HDPE cap.
No special requirements.
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