How to Switch from 20 mg Escitalopram to Desvenlafaxine (Pristiq)
When switching from escitalopram 20 mg to desvenlafaxine (Pristiq), a cross-tapering approach with gradual reduction of escitalopram while introducing desvenlafaxine at 50 mg daily is recommended to minimize discontinuation symptoms and avoid serotonin syndrome.
Cross-Tapering Schedule
Week 1:
- Reduce escitalopram to 15 mg daily
- Start desvenlafaxine 50 mg daily (therapeutic starting dose) 1
- Take both medications at different times of day to minimize risk of serotonin syndrome 2
Week 2:
- Reduce escitalopram to 10 mg daily
- Continue desvenlafaxine 50 mg daily 1
- Monitor for discontinuation symptoms or adverse effects 1
Week 3:
- Reduce escitalopram to 5 mg daily
- Continue desvenlafaxine 50 mg daily 1
- Continue monitoring for adverse effects and therapeutic response 1
Week 4:
- Discontinue escitalopram completely
- Continue desvenlafaxine 50 mg daily 1
- Assess therapeutic response and tolerability 1
Important Considerations
Discontinuation Symptoms
- Escitalopram can cause discontinuation syndrome characterized by dizziness, fatigue, headaches, nausea, sensory disturbances, anxiety, and irritability 2
- Gradual tapering reduces risk of discontinuation symptoms 2, 3
- If severe discontinuation symptoms occur, slow the taper schedule 3
Serotonin Syndrome Risk
- Both medications affect serotonin levels, creating potential risk for serotonin syndrome during cross-tapering 2, 1
- Signs of serotonin syndrome include confusion, agitation, tremors, hyperreflexia, tachycardia, diaphoresis, and hyperthermia 2
- Seek immediate medical attention if these symptoms develop 1
Dosing Considerations
- Desvenlafaxine 50 mg is both the starting and therapeutic dose 1
- Take desvenlafaxine at approximately the same time each day with or without food 1
- Swallow desvenlafaxine tablets whole with fluid; do not divide, crush, chew, or dissolve 1
Special Populations
- For patients with moderate to severe renal impairment, adjust desvenlafaxine dosing 1
- For patients with moderate to severe hepatic impairment, maximum dose is 50 mg daily 1
- For elderly patients, consider a more gradual cross-tapering schedule 2
Monitoring During Transition
- Monitor blood pressure regularly as desvenlafaxine may increase blood pressure 1
- Watch for signs of activation of mania/hypomania 1
- Assess for therapeutic response after 4 weeks on the full desvenlafaxine dose 1
- Be alert for increased risk of bleeding, especially if patient is taking NSAIDs, aspirin, or anticoagulants 1
Common Side Effects to Expect
- Nausea (most common with desvenlafaxine, typically resolves within 1-2 weeks) 1
- Headache 1
- Dizziness 1
- Insomnia or somnolence 1
- Increased sweating 1
Potential Pitfalls and How to Avoid Them
- Abrupt discontinuation: Never stop escitalopram abruptly as this significantly increases risk of discontinuation syndrome 2, 3
- Drug interactions: Avoid concomitant use with MAOIs (must wait 14 days after stopping an MAOI before starting desvenlafaxine, and 7 days after stopping desvenlafaxine before starting an MAOI) 1
- Inadequate cross-tapering: Too rapid transitions increase risk of both discontinuation symptoms and serotonin syndrome 3
- Overlooking patient factors: Adjust schedule based on individual tolerance and response 2