What are the considerations for switching a patient with depression from nortriptyline (tricyclic antidepressant) to Auvelity (dextromethorphan/bupropion) or combining them?

Switching from Nortriptyline to Auvelity: Critical Safety Considerations

Do not combine nortriptyline with Auvelity due to serious drug interaction risks, and implement a mandatory 14-day washout period when switching between these medications.

Immediate Safety Concerns

Contraindicated Combination

• Combining tricyclic antidepressants (TCAs) like nortriptyline with bupropion-containing medications is not recommended due to increased seizure risk and potential for serious adverse effects 1
• Bupropion lowers the seizure threshold, and this risk is amplified when combined with TCAs 2
• The combination has not been adequately studied for safety in depression treatment, and clinicians should proceed with extreme caution 2

Required Washout Period

• Allow at least 14 days between discontinuing nortriptyline and initiating Auvelity to minimize drug interaction risks 1
• This washout period prevents overlapping pharmacologic effects and reduces the risk of serotonin syndrome or other adverse reactions
• During the washout, monitor closely for worsening depression or emergence of suicidal ideation, particularly in patients under 24 years old 2

Switching Protocol

Step 1: Discontinue Nortriptyline

• Taper nortriptyline gradually rather than abrupt cessation to minimize withdrawal symptoms
• Monitor for return of depressive symptoms during the taper and washout period
• Assess patient weekly during this transition for safety monitoring 2

Step 2: Initiate Auvelity After Washout

• Start Auvelity at 1 tablet (dextromethorphan 45 mg/bupropion 105 mg) once daily in the morning 3, 4
• Escalate weekly: 1 tablet twice daily, then 2 tablets morning + 1 afternoon, until reaching maintenance dose of 2 tablets twice daily 2
• Avoid late-day dosing to minimize insomnia risk 2

Step 3: Early Response Monitoring

• Assess therapeutic response within 1-2 weeks of initiating Auvelity, as clinical trials demonstrated improvement as early as week 1 4, 5
• This represents a significant advantage over traditional antidepressants, which typically require 4-6 weeks for benefit 6
• Monitor for suicidal thoughts and behaviors beginning within 1-2 weeks of initiation 2

Auvelity-Specific Advantages Over Nortriptyline

Efficacy Profile

• Phase 3 trials showed significant reductions in Montgomery-Åsberg Depression Rating Scale (MADRS) scores compared to placebo, with remission rates approaching 70% in long-term studies 4
• Phase 2 trials demonstrated superiority over bupropion monotherapy 4
• Rapid onset of action (within 1-2 weeks) compared to typical 4-6 week delay with traditional antidepressants 5, 6

Safety and Tolerability

• Most common adverse effects are mild-to-moderate: dizziness, nausea, headache, diarrhea, somnolence, dry mouth, sexual dysfunction, hyperhidrosis, anxiety, constipation, decreased appetite, and insomnia 7
• Better tolerability profile than TCAs, which are associated with anticholinergic effects, cardiac conduction abnormalities, and higher risk of fatal overdose 2
• Lower sexual dysfunction rates compared to SSRIs due to bupropion component 2

Critical Contraindications and Precautions

Absolute Contraindications for Auvelity

• Seizure disorders or history of seizures - bupropion significantly lowers seizure threshold 2, 1
• Current or recent (within 14 days) MAOI use 1
• Patients requiring short-term or long-term opioid therapy (naltrexone component in some bupropion combinations antagonizes opioids) 2
• Uncontrolled hypertension 2

Dose Adjustments Required

• Moderate-to-severe hepatic impairment: Maximum 150 mg every other day 1
• Renal impairment (GFR <90 mL/min): Reduce dose and/or frequency 1
• End-stage renal disease: Avoid use 2

Monitoring Requirements

Initial Phase (Weeks 1-8)

• Weekly visits for first 2-4 weeks to assess for suicidal ideation, particularly in patients under 24 years 2
• Monitor blood pressure at each visit (bupropion can increase BP) 2
• Assess therapeutic response at week 1-2, then at weeks 4,6, and 8 2, 4

Maintenance Phase

• If no 5% improvement in depressive symptoms by week 12, discontinue medication as patient is likely a poor responder 2
• Monthly visits once stabilized for patients without comorbidities 2
• Continue monitoring for neuropsychiatric adverse effects including suicidal thoughts throughout treatment 2

Common Pitfalls to Avoid

• Never combine with TCAs - this creates unacceptable seizure risk
• Do not skip the 14-day washout period when switching from nortriptyline
• Avoid late-day dosing - increases insomnia risk
• Do not use in patients with eating disorders - significantly increased seizure risk
• Remember to hold before procedures requiring opioids if patient is on naltrexone-bupropion formulations 2

Clinical Context

While nortriptyline has historical use in depression, second-generation antidepressants like those in Auvelity are preferred first-line options due to superior safety profiles 2. The American College of Physicians recommends selecting antidepressants based on adverse effect profiles, cost, and patient preferences, with bupropion specifically noted for lower sexual dysfunction rates 2. Auvelity's unique mechanism combining NMDA receptor antagonism (dextromethorphan) with increased bioavailability via CYP2D6 inhibition (bupropion) offers a mechanistically novel approach with rapid onset 3, 4, 6.