Vilazodone

• Major Depressive Disorder
• Depression
• Mood Disorders

Vilazodone is a selective serotonin reuptake inhibitor (SSRI) and partial serotonin 5-HT1A receptor agonist used to treat major depressive disorder. This dual mechanism may provide antidepressant and anxiolytic effects.

Mechanism of Action

Vilazodone has a unique dual mechanism:

• Serotonin reuptake inhibition: Blocks SERT, increasing synaptic serotonin
• 5-HT1A partial agonism: Partial agonist at presynaptic and postsynaptic 5-HT1A receptors
• May accelerate onset: 5-HT1A partial agonism may facilitate faster antidepressant response
• Anxiolytic effects: 5-HT1A agonism contributes to anti-anxiety properties

The combination may provide enhanced serotonergic neurotransmission with potentially improved tolerability.

Available Formulations

Vilazodone is available as tablets:

• 10 mg, 20 mg, 40 mg tablets (Viibryd)

Medical Uses

FDA-Approved Indication:

• Major depressive disorder in adults

Dosing Guidelines

Adults:

• Day 1-7: 10 mg once daily with food
• Day 8-14: 20 mg once daily with food
• Day 15+: 40 mg once daily with food

Maximum dose:

• 40 mg once daily

With Strong CYP3A4 Inhibitors:

• Do not exceed 20 mg daily

With Strong CYP3A4 Inducers:

• Consider increasing dose up to 2-fold (max 80 mg/day) based on response

Discontinuation:

• Gradual dose reduction recommended to minimize withdrawal symptoms

Important Safety Information

Black Box Warning:

• Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders

Contraindications:

• Concomitant use with MAOIs or within 14 days of stopping MAOI
• Starting vilazodone in patients being treated with linezolid or IV methylene blue

Warnings and Precautions:

• Serotonin syndrome: Risk with other serotonergic drugs
• Increased bleeding risk: May impair platelet aggregation
• Activation of mania/hypomania: Use with caution in bipolar disorder
• Seizures: Use with caution in patients with seizure history
• Hyponatremia: SIADH has been reported
• Angle-closure glaucoma: May cause pupillary dilation

Drug Interactions

• MAOIs: Contraindicated; risk of serotonin syndrome
• Strong CYP3A4 inhibitors (ketoconazole, erythromycin): Limit vilazodone to 20 mg daily
• Strong CYP3A4 inducers (carbamazepine): Consider dose increase
• Serotonergic drugs (triptans, tramadol, lithium): Increased serotonin syndrome risk
• NSAIDs, aspirin, anticoagulants: Increased bleeding risk
• Drugs highly bound to plasma proteins: May displace or be displaced

Special Populations

• Hepatic Impairment: No adjustment needed
• Renal Impairment: No adjustment for mild to moderate; not studied in severe
• Elderly: No adjustment; consider slower titration
• Pregnancy: May cause persistent pulmonary hypertension and withdrawal in neonates
• Lactation: Present in breast milk; consider risk vs benefit
• Pediatric: Not approved; black box warning applies