II. Indications

III. Mechanism

  1. Selective inhibitor of vesicular monoamine transporter-2 (VMAT2)
  2. Decreases Dopamine release at nerve endings (Synapse)

IV. Efficacy

  1. Reduces symptoms by 50% with 6 weeks of treatment (Number Needed to Treat: 4)

V. Dosing

  1. Valbenazine (Ingrezza)
    1. Start 40 mg once daily and may increase to 80 mg after 1 week
    2. Target: 40-80 mg once daily
  2. Very expensive ($5000 per month)

VI. Drug Interactions

  1. Strong CYP3A4 Inhibitors (e.g. Clarithromycin, Itraconazole)
    1. Increases Valbenazine levels
    2. Limit maximum Valbenazine dose to 40 mg daily
  2. Strong CYP3A4 inducers (e.g. Carbamazepine, Phenytoin)
    1. Decreases levels
    2. Avoid while taking Valbenazine
  3. Strong CYP2D6 Inhibitors (e.g. Fluoxetine, Paroxetine)
    1. May increase Valbenazine levels and may require reduced Valbenazine doses

VII. Metabolism

  1. Liver and renal metabolism
  2. Avoid Valbenazine use in GFR <30 ml/min
  3. Consider reduced Valbenazine dose in liver Impairment

VIII. Adverse Effects

IX. Safety

  1. Pregnancy safety is unknown

X. References

  1. (2017) Presc Lett 24(6): 36
  2. LoVecchio (2018) Crit Dec Emerg Med 32(6): 32

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