Converting from Gabapentin to Pregabalin: Dosing Strategy
When converting from gabapentin to pregabalin, use a dose ratio of approximately 6:1 (gabapentin:pregabalin), with either an immediate transition or a gradual cross-titration approach depending on the clinical situation.
Conversion Ratio and Approaches
- The recommended dose conversion ratio from gabapentin to pregabalin is approximately 6:1, meaning 600 mg of gabapentin is roughly equivalent to 100 mg of pregabalin 1
- Two effective transition approaches can be used 1:
- Immediate transition: Discontinue gabapentin and start pregabalin at the next scheduled dose
- Gradual transition: Overlap therapy with 50% of gabapentin dose and 50% of target pregabalin dose for 4 days, then discontinue gabapentin and continue with full pregabalin dose
Specific Dose Conversion Examples
- Gabapentin 900 mg/day → Pregabalin 150 mg/day 1
- Gabapentin 1800 mg/day → Pregabalin 300 mg/day 1
- Gabapentin 3600 mg/day → Pregabalin 600 mg/day 1
Pregabalin Dosing Considerations
- Pregabalin has more predictable and linear pharmacokinetics than gabapentin, with high bioavailability and a half-life of approximately 6.3 hours 2
- Pregabalin can be started at an effective dose of 150 mg/day without need for titration, unlike gabapentin which requires more gradual titration 2
- Typical effective pregabalin dosing for neuropathic pain is 150-600 mg/day divided into two or three doses 3, 4
- Maximum recommended pregabalin dose is 600 mg/day (200 mg three times daily or 300 mg twice daily) 3
Special Considerations
- Both medications require dose adjustment in patients with renal impairment 3, 2
- Both medications can cause dose-dependent dizziness and sedation, which can be minimized during transition by using the gradual approach 3
- Pharmacokinetic simulations show that both transition methods result in comparable drug exposure with minimal fluctuations in therapeutic effect 1
- Pregabalin may be preferred for an initial trial given pharmacokinetics that support easier and more rapid titration compared to gabapentin 3
Common Side Effects to Monitor During Transition
- Dizziness, somnolence, and mental clouding are common with both medications 3
- Both medications can lead to weight gain and peripheral edema, especially in elderly patients 3, 5
- Side effects are typically mild to moderate and often subside within approximately 10 days of treatment initiation 6
Practical Implementation
- For patients with severe pain requiring uninterrupted analgesia, the gradual transition approach may provide more consistent pain control 1
- For patients who have experienced intolerable side effects with gabapentin, the immediate transition approach may be preferable to minimize exposure to the problematic medication 1
- Document baseline pain scores before transition to evaluate effectiveness of the conversion 3