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Vilazodone (Viibryd)

SSRI/5-HT1A partial agonist • Last reviewed 2025-09-26

General information

Vilazodone is an SSRI and 5-HT1A partial agonist approved for major depressive disorder. It was designed to combine serotonergic modulation with anxiolytic properties akin to buspirone.

Tablets (10, 20, 40 mg) must be taken with food to optimize absorption. Initial titration mitigates gastrointestinal adverse effects, which are the most common reason for discontinuation.

Vilazodone’s partial agonism may reduce sexual dysfunction risk compared with traditional SSRIs, though head-to-head data are limited.

Because of extensive CYP3A4 metabolism, coadministration with strong inhibitors (ketoconazole) necessitates a 20 mg/day maximum, whereas inducers (carbamazepine) may require alternative therapy.

Dosing & administration

10 mg once daily with food for 7 days, then 20 mg once daily for 7 days, then 40 mg once daily with food if tolerated.

Limit to 20 mg/day with strong CYP3A4 inhibitors; avoid with strong inducers if possible.

Taper gradually to minimize discontinuation symptoms.

Mechanism of action

Selectively inhibits the serotonin transporter and acts as a partial agonist at 5-HT1A receptors.

Metabolism & pharmacokinetics

Oral bioavailability increases twofold with food; administer with meals. Peak concentrations occur 4–5 hours post-dose. Extensively metabolized via CYP3A4 (primary) with minor CYP2C19 and CYP2D6 contributions. Half-life ~25 hours.

Drug interactions

Avoid MAOIs, linezolid, or methylene blue (serotonin syndrome).

Strong CYP3A4 inhibitors require 20 mg/day max; strong inducers can lower exposure.

Additive serotonergic effects with triptans, SSRIs, SNRIs; monitor for serotonin syndrome.

Monitoring & safety checks

  • Ensure administration with food

  • Monitor GI effects (diarrhea, nausea)

  • Assess for suicidality/activation

Discontinuation guidance

Taper over ≥2 weeks; withdrawal symptoms may include dizziness, irritability, or insomnia.

References

  1. Vilazodone Prescribing Information — DailyMed
  2. APA Clinical Practice Guideline for Depression (2023)
  3. CANMAT 2024 Depression Guidelines (2024)

Educational use only — verify details in current prescribing information and authoritative clinical guidelines before making prescribing decisions.