What is the safest method to taper vilazodone (Viibryd) 20 mg daily and transition to the fixed‑dose combination dextromethorphan/bupropion (Auvelity)?

Transitioning from Viibryd 20 mg to Auvelity

Stop vilazodone abruptly without tapering and begin Auvelity immediately the next day, because vilazodone is not a monoamine oxidase inhibitor and requires no washout period before starting the dextromethorphan-bupropion combination. 1

Pre-Transition Safety Screening

Before initiating Auvelity, verify the patient does not have any of the following absolute contraindications:

• Seizure history or any condition predisposing to seizures (prior head trauma, brain tumor, stroke, epilepsy) 2, 3
• Current or recent MAOI use (within 14 days) 2, 1
• Eating disorders (bulimia or anorexia nervosa) due to markedly increased seizure risk 2, 3
• Uncontrolled hypertension, as bupropion elevates blood pressure and heart rate 2, 3
• Moderate to severe hepatic impairment (maximum bupropion dose 150 mg daily in this population) 2
• Moderate to severe renal impairment (reduce bupropion dose by 50% if GFR <90 mL/min) 2, 3
• Current opioid therapy if considering any naltrexone-containing product 2

Vilazodone Discontinuation Protocol

Discontinue vilazodone 20 mg immediately without tapering. The FDA label recommends tapering only for patients on 40 mg daily (down to 20 mg for 4 days, then 10 mg for 3 days), while patients on 20 mg should taper to 10 mg for 7 days. 1 However, because you are immediately starting another antidepressant (Auvelity), abrupt discontinuation is safe and the 14-day MAOI washout rule does not apply to vilazodone. 1

Auvelity Initiation

Start Auvelity at the standard dose of one tablet (45 mg dextromethorphan/105 mg bupropion) twice daily in the morning and early afternoon (before 3 PM) on day 1. 2, 4, 5 Unlike bupropion monotherapy, Auvelity does not require gradual titration because the fixed combination is designed for immediate full dosing. 4, 5

The maximum dose is one tablet twice daily; do not exceed this to maintain seizure risk at approximately 0.1%. 2, 5

Critical Timing Considerations

• Administer the first dose in the morning to leverage bupropion's activating properties 2
• Administer the second dose before 3 PM to minimize insomnia risk, the most common side effect 2, 3, 5
• Take with or without food—unlike vilazodone, which requires food for optimal absorption, Auvelity does not have this requirement 1, 4

Early Monitoring Protocol (Weeks 1–2)

During the first 1–2 weeks after the switch, monitor intensively for:

• Suicidal ideation, agitation, irritability, or unusual behavioral changes, especially in patients younger than 24 years, as all antidepressants carry an FDA black-box warning for increased suicide risk in this age group 2, 5
• Seizure activity—the risk is approximately 0.1% (1 in 1,000) at standard Auvelity dosing 2
• Blood pressure and heart rate elevations, particularly in the first 12 weeks 2, 3
• Vilazodone discontinuation symptoms (dizziness, nausea, headache, irritability), which typically resolve within 1–2 weeks and do not require restarting vilazodone 1, 6

Expected Timeline for Clinical Response

• Early improvement in energy and motivation may occur within 1–2 weeks due to bupropion's dopaminergic/noradrenergic effects 2, 6
• Full antidepressant efficacy typically emerges by 6–8 weeks at therapeutic doses 2
• Auvelity may produce faster onset than traditional antidepressants, with some trials showing significant improvement within 1–2 weeks 4

If no adequate response occurs by 6–8 weeks, modify the treatment approach by adding cognitive-behavioral therapy, switching to a different agent, or considering augmentation strategies. 2

Common Adverse Effects and Management

The most common side effects of Auvelity include:

• Dizziness, nausea, headache, diarrhea (typically resolve within 4–5 days) 6, 5
• Insomnia (managed by ensuring second dose is before 3 PM) 2, 3, 5
• Dry mouth, somnolence, sexual dysfunction, hyperhidrosis, anxiety, constipation, decreased appetite 5

Critical Clinical Pitfalls to Avoid

• Do not taper vilazodone over weeks when switching to Auvelity—this unnecessarily prolongs subtherapeutic antidepressant coverage 1
• Do not start Auvelity at a reduced dose and titrate up—the fixed combination is designed for immediate full dosing 4, 5
• Do not skip the intensive monitoring window in weeks 1–2, as this period carries the highest risk for emergent suicidal ideation 2
• Do not exceed one tablet twice daily (total 210 mg bupropion), as seizure risk rises markedly above this threshold 2, 5
• Do not combine with MAOIs or initiate within 14 days of MAOI discontinuation 2, 1

Advantages of This Transition Strategy

This direct switch avoids the risk of a depressive relapse that can occur during prolonged antidepressant tapers or washout periods. 2 Auvelity offers potential advantages over vilazodone, including faster onset of action, dual mechanisms (NMDA antagonism plus norepinephrine/dopamine reuptake inhibition), and significantly lower rates of sexual dysfunction compared to serotonergic agents. 2, 4