Tardive Dyskinesia
- PO (Adults ): 40 mg once daily; after 1 wk, ↑ to 80 mg once daily. Known CYP2D6 poor metabolizer: 40 mg once daily (with no additional titration). Concurrent use of strong CYP3A4 inhibitors or strong CYP2D6 inhibitors: 40 mg once daily (with no additional titration).
Hepatic Impairment
- PO (Adults ): Moderate or severe hepatic impairment: 40 mg once daily (with no additional titration).
Chorea Associated with Huntington's Disease
- PO (Adults ): 40 mg once daily; ↑ by 20 mg/day every 2 wk until achieve recommended dose of 80 mg once daily. Known CYP2D6 poor metabolizer: 40 mg once daily (with no additional titration). Concurrent use of strong CYP3A4 inhibitors or strong CYP2D6 inhibitors: 40 mg once daily (with no additional titration).
Hepatic Impairment
- PO (Adults ): Moderate or severe hepatic impairment: 40 mg once daily (with no additional titration).
Therapeutic Classification: none assigned
Pharmacologic Classification: reversible monoamine depleters
Absorption: 49% absorbed following oral administration.
Distribution: Well distributed to tissues.
Protein Binding: >99%.
Metabolism/Excretion: Rapidly and extensively metabolized by the liver via hydrolysis to the active metabolite, α-dihydrotetrabenazine (α-HTBZ); also metabolized via the CYP3A4 isoenzyme to form other minor metabolites. α-HTBZ is further metabolized, in part, via the CYP2D6 isoenzyme. The CYP2D6 isoenzyme exhibits genetic polymorphism; 7% of population may be poor metabolizers and may have significantly ↑ concentrations and an ↑ risk of adverse effects. 60% eliminated in urine (<2% as unchanged drug) and 30% eliminated in feces (<2% as unchanged drug).
Half-Life: 1522 hr (valbenazine and α-HTBZ).