How to switch from Wellbutrin (bupropion) 400mg to venlafaxine?

Switching from Bupropion 400mg to Venlafaxine

When switching from bupropion 400mg to venlafaxine, use a cross-taper approach starting with venlafaxine 37.5mg once or twice daily while gradually reducing bupropion, with complete transition occurring over 1-2 weeks. 1

Initial Steps

• Begin venlafaxine at 37.5mg once or twice daily while maintaining current bupropion dose 1
• After 3-4 days of combined therapy, reduce bupropion to 300mg daily (divided doses) 2
• Monitor for potential drug interactions and adverse effects during the overlap period 3

Titration Schedule

Week 1

• Days 1-3: Start venlafaxine 37.5mg once or twice daily + maintain bupropion 400mg 1
• Days 4-7: Increase venlafaxine to 75mg daily + reduce bupropion to 300mg daily 1, 2

Week 2

• Days 8-10: Increase venlafaxine to 150mg daily + reduce bupropion to 150mg daily 1
• Days 11-14: Continue venlafaxine 150mg daily + discontinue bupropion 3

Week 3 and beyond

• Titrate venlafaxine as needed up to maximum 225mg daily based on response 1

Monitoring During Transition

• Assess for serotonin syndrome symptoms during the cross-taper period (agitation, tremor, hyperthermia, autonomic instability) 3
• Monitor blood pressure closely as venlafaxine can cause increases, particularly at doses above 150mg daily 1
• Watch for withdrawal symptoms from bupropion reduction (irritability, anxiety, insomnia) 3, 4
• Schedule follow-up within 2 weeks of initiating the switch to assess efficacy and side effects 1

Special Considerations

• For patients with cardiac disease, use venlafaxine with caution due to potential cardiac conduction abnormalities 1
• If insomnia occurs during transition, consider administering venlafaxine earlier in the day 2
• Venlafaxine must be tapered when discontinuing due to risk of withdrawal syndrome 1
• If intolerable side effects develop during cross-tapering, consider accelerating the taper of one medication while maintaining the other 4

Expected Outcomes and Timeline

• Full therapeutic effect of venlafaxine typically requires 4-6 weeks 1
• Withdrawal symptoms from bupropion typically peak within 1-2 weeks of cessation 1
• Approximately 25% of patients achieve remission when switching between antidepressants 5

Common Pitfalls to Avoid

• Avoid abrupt discontinuation of either medication to prevent withdrawal symptoms 3, 4
• Do not exceed venlafaxine 225mg daily without specialist consultation 1
• If patient has seizure history, exercise additional caution as both medications may affect seizure threshold 2
• For patients with renal or hepatic impairment, use lower doses and slower titration of both medications 2

This cross-tapering approach balances the need to maintain antidepressant coverage while minimizing the risk of drug interactions and withdrawal symptoms, optimizing the transition between these mechanistically different antidepressants.