From the FDA Drug Label
INGREZZA was started at 40 mg per day and the dose could be increased every 2 weeks in 20 mg increments up to a maximum dosage of 80 mg per day
The maximum dose of Ingrezza (valbenazine) that can be prescribed is 80 mg per day. Since the patient is already taking 80mg at bedtime, the dose should not be increased further. 1 1
From the Research
The maximum dose of Ingrezza (valbenazine) for a 69-year-old patient experiencing twitching and shaky movements while taking 80mg at bedtime is 80mg once daily, which is already the maximum recommended dose, and according to the most recent study 2, no further dose increase is recommended. For this patient who is experiencing adverse effects at the maximum dose, a dose reduction to 40mg once daily would be appropriate to manage these side effects while still providing therapeutic benefit. Twitching and shaky movements suggest the patient may be experiencing treatment-emergent adverse effects, which commonly include somnolence, balance disorders, and akathisia, as noted in various studies 3, 4, 5. If symptoms persist after dose reduction, the healthcare provider should reassess the benefit-risk profile of continuing Ingrezza therapy. Elderly patients (65 years and older) may be more sensitive to medication effects due to age-related changes in pharmacokinetics and pharmacodynamics, so careful monitoring is essential, as highlighted in the study 2. The medication should be taken with or without food at approximately the same time each day to maintain consistent blood levels. Key points to consider in managing this patient include:
- Monitoring for treatment-emergent adverse effects
- Adjusting the dose as needed to balance efficacy and tolerability
- Considering alternative treatments if Ingrezza is not effective or is poorly tolerated
- Regularly assessing the patient's overall condition and adjusting the treatment plan accordingly, taking into account the findings from the study 6 on the differences between drug-induced parkinsonism and tardive dyskinesia.