What SSNRI (Selective Serotonin and Norepinephrine Reuptake Inhibitor) can be switched with Wellbutrin (bupropion) 400mg at the same dosing?

Switching from Wellbutrin 400mg to an SSNRI

When switching from Wellbutrin (bupropion) 400mg to an SSNRI, duloxetine is the recommended first-line choice, starting at 30mg daily and titrating to 60mg daily after one week, with a maximum dose of 120mg daily. 1

Recommended SSNRI Options

• Duloxetine is the preferred first-line SSNRI when switching from bupropion due to its established efficacy and favorable safety profile compared to other options 1
• Venlafaxine is an alternative option, starting at 37.5mg once or twice daily and increasing by 75mg each week to a maximum of 225mg daily 1
• Desvenlafaxine or milnacipran are other possible alternatives but have less robust evidence for efficacy compared to duloxetine 1

Switching Protocol

Direct Switch Approach

• For patients without complex comorbidities, a direct switch from bupropion 400mg to duloxetine 30mg daily is appropriate 2, 3
• After one week on 30mg, increase duloxetine to 60mg daily if tolerated 1
• An adequate trial requires at least 4 weeks at therapeutic dosage 1

Cross-Taper Approach

• For patients with more severe depression or anxiety, consider a cross-taper approach 2
• Begin duloxetine 30mg while reducing bupropion to 300mg for 3-4 days
• Increase duloxetine to 60mg while reducing bupropion to 200mg for another 3-4 days
• Continue duloxetine 60mg and discontinue bupropion 2, 3

Monitoring and Considerations

• Monitor for serotonin syndrome, especially if the patient was on other serotonergic medications along with bupropion 4
• Be aware that bupropion and SSNRIs have different mechanisms of action - bupropion primarily affects dopamine and norepinephrine, while SSNRIs affect serotonin and norepinephrine 5, 6
• Expect different side effect profiles:
  • Bupropion is associated with less sexual dysfunction and sedation than SSNRIs 5
  • SSNRIs may cause more nausea, dizziness, and potential blood pressure increases 1
• Cardiac monitoring may be necessary when switching to venlafaxine, as it can cause cardiac conduction abnormalities and blood pressure increases 1

Cautions and Contraindications

• Avoid abrupt discontinuation of either medication; always taper to prevent withdrawal symptoms 1
• Use caution when prescribing SSNRIs to patients with cardiac disease due to potential blood pressure effects and cardiac conduction issues 1
• Consider renal function when dosing SSNRIs; both duloxetine and venlafaxine may require dose adjustments in patients with renal impairment 1
• Be cautious about drug interactions, particularly with medications that affect the cytochrome P450 system 7

Efficacy Considerations

• Response rates after switching from one antidepressant to another are approximately 25%, regardless of which medication is chosen 6
• The number of previous antidepressant trials negatively correlates with treatment outcomes 3
• There is no clear evidence that switching between classes (from bupropion to an SSNRI) is superior to switching within classes 3, 6