What is the recommended tapering schedule for switching a patient from 300mg gabapentin (Neurontin) twice daily to Lyrica (pregabalin) for neuropathy?

Switching from Gabapentin to Pregabalin for Neuropathy

When switching a patient from gabapentin 300mg twice daily to pregabalin for neuropathy, the recommended approach is to start pregabalin at 75mg twice daily while tapering gabapentin over 1 week, then titrate pregabalin to a target dose of 300mg daily as needed for pain control. 1, 2

Conversion Schedule

Week 1: Overlap and Initial Taper

• Day 1-3: Continue gabapentin 300mg in the morning, reduce to 300mg at bedtime; Start pregabalin 75mg in the evening
• Day 4-7: Discontinue morning gabapentin, continue 300mg at bedtime; Increase pregabalin to 75mg twice daily

Week 2: Complete Switch

• Day 8 onward: Discontinue gabapentin completely
• Continue pregabalin 75mg twice daily (150mg/day)

Week 3-4: Pregabalin Titration (if needed)

• If pain control is inadequate after 1 week on pregabalin alone, increase to 150mg twice daily (300mg/day)
• Maximum recommended dose is 300mg twice daily (600mg/day) if needed for pain control 1

Rationale for This Approach

1. Pharmacological Equivalence: Pregabalin has higher bioavailability (>90%) compared to gabapentin's variable absorption, making it more potent at lower doses 2

2. Conversion Ratio: A gabapentin dose of 300mg twice daily (600mg/day) approximately converts to pregabalin 150mg/day initially 2

3. Avoiding Withdrawal: Gradual tapering of gabapentin prevents withdrawal symptoms while introducing pregabalin 2

4. Minimizing Side Effects: Overlap period helps maintain pain control while minimizing the risk of increased side effects from both medications 2

Monitoring Recommendations

• Assess for common side effects during transition: dizziness, somnolence, peripheral edema, and gait disturbance 1, 2
• Evaluate pain control after 1-2 weeks on pregabalin alone
• Adjust dose based on efficacy and tolerability
• Monitor renal function as both medications require dose adjustment in renal impairment 2

Advantages of Pregabalin over Gabapentin

• Better bioavailability (>90% vs. decreasing with higher doses for gabapentin) 2
• Simpler dosing (twice daily vs. three times daily) 2
• Faster titration possible (days vs. weeks) 2
• More predictable dose-response relationship 3

Common Pitfalls to Avoid

• Abrupt discontinuation: Never stop gabapentin suddenly as this can cause withdrawal symptoms 2
• Underdosing pregabalin: Starting at too low a dose may result in inadequate pain control 2
• Overly rapid titration: Increasing doses too quickly increases risk of adverse effects 2
• Failure to adjust for renal impairment: Both medications require dose adjustment in patients with reduced renal function 2

This conversion schedule balances the need for continued pain control with minimizing the risk of side effects during the transition period, while providing a clear pathway to effective pregabalin dosing.