Switching from Lexapro 20mg to Effexor
Use a conservative cross-taper approach: gradually reduce escitalopram while simultaneously introducing venlafaxine at a low starting dose, monitoring closely for both discontinuation symptoms and serotonin syndrome over 2-4 weeks. 1
Recommended Switching Strategy
Week 1-2: Initiate Cross-Taper
- Start venlafaxine XR at 37.5 mg once daily while continuing escitalopram 20mg 2
- Monitor for early adverse effects, particularly nausea (most common with venlafaxine initiation) 2
- Watch for signs of serotonin syndrome during co-administration, though risk is relatively low with this combination 1
Week 2-3: Reduce Escitalopram
- Decrease escitalopram from 20mg to 10mg daily while maintaining venlafaxine XR 37.5mg 3
- Gradual reduction minimizes discontinuation symptoms including dizziness, fatigue, headaches, nausea, insomnia, and anxiety 3
- Continue monitoring for withdrawal symptoms versus relapse of underlying condition 3
Week 3-4: Complete Transition
- Discontinue escitalopram completely and increase venlafaxine XR to 75mg daily 2
- This represents the minimum therapeutic dose for venlafaxine 2
Week 4-8: Titrate to Therapeutic Dose
- Increase venlafaxine by 75mg weekly as tolerated to reach target dose of 150-225mg/day 2
- Most patients require 2-4 weeks to reach efficacious dosing 2
- Allow 4-6 weeks at therapeutic dose for adequate trial 2
Critical Monitoring Parameters
Cardiovascular Considerations
- Check blood pressure at each dose increase - venlafaxine can cause dose-dependent BP elevations 2
- Use caution in patients with cardiac disease due to rare cardiac conduction abnormalities 2
- Consider baseline ECG if patient has cardiac risk factors 2
Discontinuation Symptoms
- Escitalopram has shorter half-life than some SSRIs, increasing discontinuation risk with abrupt cessation 3, 1
- Venlafaxine itself requires tapering when eventually discontinued due to well-described withdrawal syndrome 2
- More venlafaxine-treated patients experience discontinuation symptoms compared to escitalopram when stopping treatment 4
Evidence Supporting This Approach
Comparative Efficacy
- Both medications demonstrate efficacy for depression and generalized anxiety disorder 5, 6, 4
- Venlafaxine XR separated from placebo more robustly than escitalopram in GAD trials, though escitalopram showed better tolerability 5
- In severely depressed patients (MADRS ≥30), escitalopram 20mg showed higher remission rates (47%) than venlafaxine XR (29%), but this is switching from escitalopram, suggesting inadequate response 6
Tolerability Profile
- Venlafaxine has higher discontinuation rates due to adverse events (11-13%) compared to escitalopram (7-7.5%) 5, 6
- Nausea, constipation, and increased sweating occur more frequently with venlafaxine 4
- Venlafaxine discontinuation produces significantly more withdrawal symptoms (mean 5.0) than escitalopram (mean 2.4) 6
Common Pitfalls to Avoid
- Never abruptly stop escitalopram - this significantly increases risk of discontinuation syndrome 3, 1
- Do not rush the venlafaxine titration - rapid increases worsen nausea and other side effects 2
- Avoid combining with other serotonergic agents without careful consideration of serotonin syndrome risk 1
- Do not assume treatment failure before 4-6 weeks at therapeutic venlafaxine dose (150-225mg/day) 2