Generic Name

Valbenazine

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Classification

FDA Approved Indications

• Tardive Dyskinesia

Mechanism of Action

Valbenazine inhibits VMAT2, reducing the uptake of monoamines into synaptic vesicles, which decreases monoamine release and alleviates hyperkinetic movement disorders like tardive dyskinesia.

Dosage and Administration

Adult: Start at 40 mg once daily. May increase to 80 mg once daily based on response and tolerability.

Pediatric: Not approved for pediatric use.

Geriatric: Use with caution; start at lower doses due to age-related sensitivity.

Renal Impairment: No dosage adjustment necessary for mild to moderate impairment; use caution in severe impairment.

Hepatic Impairment: Use caution; no specific dosage adjustment established.

Pharmacokinetics

Absorption: Rapidly absorbed with peak concentrations in 1-3 hours.

Distribution: Widely distributed; protein binding approximately 99%.

Metabolism: Primarily hepatic via CYP3A4 and CYP2D6 pathways.

Excretion: Excreted mainly in feces and urine.

Half Life: Approximately 15 hours.

Contraindications

• Hypersensitivity to valbenazine
• Concurrent use with reversible monoamine oxidase inhibitors (MAOIs).

Precautions

• Use with caution in patients with cardiovascular disease, suicidal ideation, or history. Monitor for tardive dyskinesia worsening.

Adverse Reactions - Common

• Sleepiness or sedation (Common)
• Headache (Common)
• decreased blood pressure (hypotension) (Common)

Adverse Reactions - Serious

• QT prolongation (Serious)
• Neuroleptic malignant syndrome (Serious)
• Tardive dyskinesia worsening (Serious)

Drug-Drug Interactions

• CYP3A4 inhibitors (e.g., ketoconazole) may increase valbenazine levels.
• CYP3A4 inducers (e.g., rifampin) may decrease efficacy.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication as prescribed, at the same time each day.
• Report signs of abnormal movements, dizziness, or fainting.
• Avoid alcohol and other CNS depressants.
• Inform about potential for QT prolongation and avoid concurrent use of other QT-prolonging drugs.

Special Considerations

Black Box Warnings:

• QT prolongation and sudden death in overdose.
• Potential for neuroleptic malignant syndrome.

Genetic Factors: Consider CYP2D6 metabolizer status for dose adjustments.

Lab Test Interference: None noted.

Overdose Management

Signs/Symptoms: Drowsiness, sedation, hypotension, QT prolongation.

Treatment: Supportive care, monitor cardiac status, and provide symptomatic treatment. No specific antidote.

Storage and Handling

Storage: Store at room temperature, 20-25°C (68-77°F).

Stability: Stable through expiration date when stored properly.