From the FDA Drug Label
DOSAGE AND ADMINISTRATION • ... • Maximum daily dose in PMs: 50 mg with a maximum single dose of 25 mg (2.2) • Maximum daily dose in EMs and intermediate metabolizers (IMs): 100 mg with a maximum single dose of 37.5 mg (2.2) The maximum dose of tetrabenazine (Xenazine) for tardive dyskinesia is:
- 100 mg per day for extensive metabolizers (EMs) and intermediate metabolizers (IMs)
- 50 mg per day for poor metabolizers (PMs) 1
From the Research
The maximum recommended dose of tetrabenazine for tardive dyskinesia is not explicitly stated in the most recent and highest quality study, but based on the available evidence, the maximum dose should not exceed 100 mg per day, typically divided into three doses. Start with a low dose of 12.5 mg once or twice daily and gradually increase by 12.5 mg weekly based on response and tolerability, as seen in studies such as 2. The usual maintenance dose range is 25-75 mg per day in divided doses, and it is crucial not to exceed 50 mg in a single dose, especially for patients who are CYP2D6 poor metabolizers, as noted in general clinical guidelines. Patients who are CYP2D6 poor metabolizers should not exceed 50 mg per day total, and genetic testing for CYP2D6 status may be considered before initiating high doses, as suggested by various studies including 3. It is essential to monitor closely for side effects, particularly depression and suicidal thoughts, and start at lower doses in elderly patients or those with hepatic impairment, as indicated by the safety profiles of VMAT-2 inhibitors in studies like 4. Tetrabenazine works by depleting dopamine in the brain, which helps reduce the abnormal involuntary movements associated with tardive dyskinesia, and the gradual dose titration allows for finding the optimal balance between symptom control and side effects for each individual patient, as demonstrated in the efficacy and safety data from studies such as 2 and 4. Some key points to consider when prescribing tetrabenazine include:
- Gradual dose titration to minimize side effects
- Close monitoring for depression, suicidal thoughts, and other adverse effects
- Consideration of CYP2D6 status for dose adjustment
- Starting with lower doses in vulnerable populations such as the elderly or those with hepatic impairment
- The importance of individualizing the dose based on response and tolerability, as highlighted in studies like 2 and 4.