Gabapentin Dosing Recommendations
For neuropathic pain in adults, start gabapentin at 300 mg once daily on day 1, increase to 300 mg twice daily on day 2, then 300 mg three times daily (900 mg/day) on day 3, and titrate upward by 300 mg every 3-7 days to reach the target therapeutic dose of 1800-3600 mg/day in three divided doses. 1, 2
Initial Dosing and Titration Schedule
The FDA-approved titration schedule provides the foundation for safe initiation: 1
- Day 1: 300 mg once daily (preferably at bedtime)
- Day 2: 300 mg twice daily (600 mg/day total)
- Day 3: 300 mg three times daily (900 mg/day total)
- Days 4+: Increase by 300 mg every 3-7 days as tolerated
The minimum effective dose for most neuropathic pain conditions is 1800 mg/day (600 mg three times daily), with a maximum dose of 3600 mg/day (1200 mg three times daily) for optimal pain relief. 2, 1
Target Therapeutic Dose Range
For postherpetic neuralgia and painful diabetic neuropathy, doses of 1800-3600 mg/day demonstrate moderate-quality evidence for efficacy, with 32-38% of patients achieving at least 50% pain reduction versus 17-21% with placebo. 2, 3 The FDA label confirms that efficacy was demonstrated across this dose range, though additional benefit above 1800 mg/day was not consistently demonstrated in clinical trials. 1
Critical Dosing Considerations
Three-times-daily dosing is mandatory for standard gabapentin due to its saturable absorption pharmacokinetics—once or twice daily dosing is inadequate. 2 The maximum time between doses should not exceed 12 hours. 1
Gabapentin has nonlinear pharmacokinetics, meaning dose increases do not produce proportional increases in blood levels above 1800 mg/day, making titration less predictable than other medications. 2, 4
Special Population Adjustments
Elderly or Medically Frail Patients
Start at the lower end of the dosing range (100 mg at bedtime) and use slower titration with increases every 3-7 days to minimize fall risk from dizziness. 2
Renal Impairment
Mandatory dose reduction is required based on creatinine clearance, as gabapentin is eliminated primarily by renal excretion: 2, 1
- 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 single daily dose
- CrCl <15 mL/min: 100-300 mg/day as single daily dose
- Hemodialysis patients: Maintenance dose based on CrCl plus supplemental 125-350 mg post-dialysis dose
Timeline for Therapeutic Assessment
Allow a minimum trial duration of 3-8 weeks for titration plus 2 weeks at maximum tolerated dose—an adequate therapeutic trial may require 2 months or more, as efficacy for neuropathic pain develops gradually over several weeks. 2 Do not declare treatment failure prematurely.
Common Adverse Effects
The most common side effects include dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (14%), which are typically mild to moderate and often transient. 2, 3 Adverse event withdrawals occur in approximately 11% of patients versus 8.2% with placebo. 3
Discontinuation Protocol
When discontinuing gabapentin, taper gradually over at least 1 week (longer periods may be needed at prescriber discretion) to avoid withdrawal symptoms. 1, 2
Condition-Specific Notes
Epilepsy (Partial Onset Seizures)
For patients 12 years and older, start at 300 mg three times daily and titrate to a maintenance dose of 300-600 mg three times daily. Dosages up to 2400 mg/day have been well tolerated in long-term studies, with doses up to 3600 mg/day administered to some patients. 1
Pediatric Epilepsy (Ages 3-11)
Start at 10-15 mg/kg/day in three divided doses, titrating over approximately 3 days to maintenance doses of 40 mg/kg/day for ages 3-4 or 25-35 mg/kg/day for ages 5-11. 1