What is the recommended dosage of Gabapentin (Neurontin) for nerve pain?

Gabapentin Dosing for Nerve Pain

For neuropathic pain, gabapentin should be started at 100-300 mg at bedtime or 100-300 mg three times daily, with gradual titration to 900-3600 mg/day in divided doses over 3-8 weeks. 1, 2, 3

Initial Dosing and Titration

• Start with 100-300 mg at bedtime or 100-300 mg three times daily 1, 2, 3
• Increase by 100-300 mg every 1-7 days as tolerated 1, 4
• Target effective dose range: 900-3600 mg/day in divided doses (typically three times daily) 1, 2, 4
• Maximum dose should not exceed 3600 mg/day 1, 4

Duration of Treatment Trial

• An adequate trial requires 3-8 weeks for titration plus 2 weeks at maximum dose to properly evaluate efficacy 1, 3
• Complete pain relief may take several weeks to achieve optimal effect 2

Dosage Adjustments for Special Populations

• Elderly patients: Start at lower doses and titrate more slowly 1, 2, 4
• Renal impairment: Dosage reduction required based on creatinine clearance 1, 2, 4
  • For creatinine clearance 30-59 mL/min: 400-1400 mg/day in divided doses
  • For creatinine clearance 15-29 mL/min: 200-700 mg/day in single daily dose
  • For creatinine clearance <15 mL/min: 100-300 mg/day in single daily dose 4

Efficacy for Different Types of Neuropathic Pain

• Postherpetic neuralgia: 38% of patients achieve substantial pain relief (≥50% reduction) compared to 21% with placebo 5
• Diabetic neuropathy: 38% of patients achieve substantial pain relief compared to 21% with placebo 5
• Doses of 1800-3600 mg/day provide good levels of pain relief for these conditions 5

Side Effects and Monitoring

• Common side effects include dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (14%) 5
• Side effects are typically mild to moderate and often transient, usually subsiding within approximately 10 days from treatment initiation 6
• Risk of falls or fractures increases with doses ≥600 mg/day (RR 1.35) 7
• Monitor for altered mental status, especially at higher doses 7

Clinical Pearls

• Gabapentin has nonlinear pharmacokinetics due to saturable absorption, requiring careful titration 1
• Dividing the daily dose into three administrations helps minimize peak-related side effects 1, 4
• The maximum time between doses should not exceed 12 hours 4
• If using scored tablets (600 mg or 800 mg), unused half-tablets should be taken as the next dose and discarded if not used within 28 days 4
• If discontinuing gabapentin, taper gradually over at least 1 week to avoid withdrawal symptoms 4

Comparative Efficacy

• While doses up to 3600 mg/day have been studied, doses above 1800 mg/day may not provide additional benefit for postherpetic neuralgia 4
• For diabetic neuropathy and other neuropathic pain conditions, doses between 1800-3600 mg/day may be needed for optimal effect 6