What are the dosing guidelines for Gabapentin (Neurontin)?

Gabapentin Dosing Guidelines

Gabapentin should be initiated at 100-300 mg at bedtime, then gradually titrated to 900-3600 mg daily in divided doses (2-3 times daily), with dose adjustments based on renal function and patient response. 1, 2

General Dosing Recommendations

Initial Dosing and Titration

• Start with 100-300 mg at bedtime or 300 mg once daily 1, 2
• Increase by 300 mg increments every 3-7 days as tolerated 1, 2
• Slower titration recommended for elderly or medically frail patients 1
• Typical effective maintenance dose range: 900-3600 mg/day in divided doses 1, 2

Administration Schedule

• Divide total daily dose into 2-3 administrations per day 2
• Maximum time between doses should not exceed 12 hours 2
• Can be taken with or without food 2

Indication-Specific Dosing

Neuropathic Pain

• Postherpetic Neuralgia: Start with 300 mg on day 1,600 mg on day 2 (300 mg twice daily), 900 mg on day 3 (300 mg three times daily) 2
• Recommended maintenance dose: 1800 mg/day (600 mg three times daily) 2
• Higher doses up to 3600 mg/day may be needed in some patients but additional benefit beyond 1800 mg/day has not been consistently demonstrated 2, 3

Epilepsy

• Adults and children ≥12 years: Start with 300 mg three times daily 2
• Maintenance dose: 300-600 mg three times daily (900-1800 mg/day) 2
• Doses up to 2400 mg/day have been well tolerated in long-term studies 2

Pediatric Dosing (3-11 years, for epilepsy)

• Starting dose: 10-15 mg/kg/day in three divided doses 2
• Maintenance dose:
  • Ages 3-4 years: 40 mg/kg/day in three divided doses 2
  • Ages 5-11 years: 25-35 mg/kg/day in three divided doses 2

Dosage Adjustment in Special Populations

Renal Impairment

• Dosage adjustment required based on creatinine clearance 1, 2:
  • CrCl ≥60 mL/min: 900-3600 mg/day in three divided doses
  • CrCl 30-59 mL/min: 400-1400 mg/day in two divided doses
  • CrCl 15-29 mL/min: 200-700 mg/day as a single daily dose
  • CrCl <15 mL/min: 100-300 mg/day as a single daily dose

Hemodialysis Patients

• Maintenance dose based on creatinine clearance plus supplemental post-hemodialysis dose 2
• Supplemental dose ranges from 125-350 mg after each 4-hour hemodialysis session 2

Elderly Patients

• Start at lower doses and titrate more slowly 1, 2
• Adjust dose based on creatinine clearance values 2

Monitoring and Side Effects

Common Side Effects

• Dizziness and somnolence (most common) 1, 3, 4
• Side effects are typically mild to moderate and often transient 3
• Most adverse effects occur during titration phase and subside within approximately 10 days 3

Discontinuation

• If discontinuing gabapentin, taper gradually over a minimum of 1 week to avoid withdrawal symptoms 2

Clinical Pearls

• Efficacy for neuropathic pain may take several weeks to achieve optimal effect 1, 3
• Gabapentin has a favorable safety profile with minimal drug interactions 1
• For optimal pain control, individualize dosing based on efficacy and tolerability 3
• Lower doses (100-300 mg/day) may be effective for certain conditions like carpal tunnel syndrome 5