What is the recommended dose and frequency of gabapentin (Neurontin) for treating neuropathy?

Gabapentin Dosing for Neuropathic Pain

For neuropathic pain, gabapentin should be initiated at 100-300 mg at bedtime or 100-300 mg three times daily, then titrated by 100-300 mg every 1-7 days as tolerated, up to a maximum of 3600 mg/day in 3 divided doses, with an adequate trial requiring 3-8 weeks for titration plus 2 weeks at maximum dose. 1

Initial Dosing and Titration

• Starting dose: 100-300 mg at bedtime or 100-300 mg three times daily 1
• Titration schedule: Increase by 100-300 mg every 1-7 days as tolerated 1
• Recommended titration example:
  • Day 1: 300 mg once daily
  • Day 2: 300 mg twice daily (600 mg/day)
  • Day 3: 300 mg three times daily (900 mg/day)
  • Then continue gradual titration as needed for pain relief 2

Target and Maximum Dosing

• Effective dose range: 900-3600 mg/day in divided doses 1, 2
• Most common effective dose: 1800 mg/day (600 mg three times daily) 2
• Maximum recommended dose: 3600 mg/day in three divided doses 1, 2
• Dosing frequency: Three times daily with maximum time between doses not exceeding 12 hours 2

Duration of Treatment

• Adequate trial duration: 3-8 weeks for titration plus 2 weeks at maximum tolerated dose 1
• Time to efficacy assessment: An adequate trial may require 2 months or more 1

Dosage Adjustment in Special Populations

Renal Impairment

Dosage adjustment based on creatinine clearance (CrCl) 2:

• CrCl ≥60 mL/min: 900-3600 mg/day (300 mg TID to 1200 mg TID)
• CrCl 30-59 mL/min: 400-1400 mg/day (200-700 mg BID)
• CrCl 15-29 mL/min: 200-700 mg/day (200-700 mg QD)
• CrCl <15 mL/min: 100-300 mg/day (100-300 mg QD)

Elderly Patients

• Lower starting doses and slower titration recommended 1, 2
• Dose should be adjusted based on creatinine clearance values 2

Clinical Efficacy and Evidence

• Gabapentin is effective for various neuropathic pain conditions including postherpetic neuralgia, diabetic neuropathy, and spinal cord injury-related pain 1, 3, 4
• At doses of 1200 mg/day or greater, approximately 38% of patients with diabetic neuropathy and 32% of patients with postherpetic neuralgia achieve at least 50% pain relief 3
• Gabapentin relieves symptoms of allodynia, burning pain, shooting pain, and hyperesthesia 5

Adverse Effects and Monitoring

• Most common adverse effects: dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (14%) 3
• Adverse effects are typically mild to moderate and usually subside within approximately 10 days from treatment initiation 5
• Adverse event withdrawals occur in approximately 11% of patients 3
• Monitor for side effects, especially during titration phase

Clinical Pearls and Pitfalls

• Pitfall: Inadequate dosing or insufficient trial duration may lead to treatment failure
• Pearl: Starting with lower doses and gradual titration improves tolerability
• Pitfall: Not adjusting dose in patients with renal impairment can lead to toxicity
• Pearl: Complete pain relief is often not achievable; aim for 30-50% pain reduction 6
• Pitfall: Stopping gabapentin abruptly may cause withdrawal symptoms; taper gradually when discontinuing

Comparison with Alternative Treatments

• Pregabalin has similar efficacy but more straightforward dosing due to linear pharmacokinetics 1
• Pregabalin may provide analgesia more quickly than gabapentin because the initial dosage of 150 mg/day has been found to be efficacious in some trials 1
• The American Diabetes Association recommends pregabalin, duloxetine, or gabapentin as initial pharmacologic treatments for neuropathic pain in diabetes 6