Transitioning from Gabapentin 1200mg/day to Pregabalin (Lyrica)
To transition a patient from gabapentin 1200mg/day to pregabalin, start pregabalin at 150mg/day (75mg twice daily) while tapering gabapentin over 1 week, then increase pregabalin to a target dose of 300mg/day (150mg twice daily). 1
Conversion Rationale and Protocol
Pregabalin is more efficiently absorbed through the GI tract than gabapentin, requiring dose adjustment when transitioning between these medications. The conversion follows this algorithm:
Day 1-3:
- Reduce gabapentin to 900mg/day (300mg TID)
- Start pregabalin 75mg twice daily (150mg/day)
Day 4-7:
- Reduce gabapentin to 600mg/day (300mg BID)
- Continue pregabalin 75mg twice daily
Day 8-10:
- Discontinue gabapentin
- Increase pregabalin to 150mg twice daily (300mg/day)
This gradual transition helps minimize withdrawal symptoms while maintaining pain control throughout the process.
Dose Equivalence Considerations
Gabapentin 1200mg/day is approximately equivalent to pregabalin 150-300mg/day based on clinical efficacy. Pregabalin has higher bioavailability (>90%) compared to gabapentin (33-66%), requiring lower doses to achieve similar effects 1.
Monitoring During Transition
- Pain control: Assess pain scores before and during transition
- Side effects: Monitor for dizziness, somnolence, and peripheral edema
- Withdrawal symptoms: Watch for anxiety, insomnia, headache, nausea
Special Considerations
- Renal function: Dose adjustment required for patients with renal insufficiency (CrCl <60 ml/min) 1, 2
- Elderly patients: Consider slower titration with lower doses
- Risk of misuse: Both medications carry potential for dependence and abuse 3
Advantages of Pregabalin over Gabapentin
Pregabalin offers:
- More predictable absorption
- Faster onset of action
- Twice-daily dosing instead of 3-4 times daily
- Linear pharmacokinetics
Common Pitfalls to Avoid
- Abrupt discontinuation: Never stop gabapentin suddenly as this may precipitate withdrawal symptoms
- Inadequate pregabalin dosing: Underdosing pregabalin during transition can lead to breakthrough pain
- Overlapping side effects: Monitor for additive sedation during the overlap period
- Ignoring renal function: Both drugs require dose adjustment in renal impairment
- Missing doses: Educate patient about the importance of adherence during transition
While some clinicians have used combination therapy with both agents 4, this approach is not standard practice and should be avoided during a planned transition from one agent to the other.