What is the maximum recommended daily dose of gabapentin (Neurontin) for an adult patient?

Maximum Daily Dose of Gabapentin

The maximum recommended daily dose of gabapentin is 3600 mg/day, divided into three doses (1200 mg three times daily), as established by the FDA label and supported by clinical guidelines. 1

FDA-Approved Maximum Dosing

• The FDA label explicitly states that doses of 3600 mg/day have been administered to patients for relatively short durations and have been well tolerated 1
• For postherpetic neuralgia specifically, the FDA notes that efficacy was demonstrated over a range of 1800-3600 mg/day, though additional benefit of doses greater than 1800 mg/day was not consistently demonstrated in clinical studies 1
• For epilepsy with partial onset seizures in patients ≥12 years, dosages up to 2400 mg/day have been well tolerated in long-term clinical studies, with 3600 mg/day administered to a smaller number of patients 1

Clinical Guideline Recommendations

• The National Comprehensive Cancer Network and American Academy of Neurology recommend a target therapeutic dose range of 1800-3600 mg/day in three divided doses for neuropathic pain 2
• The maximum dose of 3600 mg/day (1200 mg three times daily) may be needed for optimal pain relief in patients who do not achieve adequate response at 1800 mg/day 2
• Three-times-daily dosing is essential due to gabapentin's saturable, nonlinear absorption pharmacokinetics 2

Critical Dosing Considerations

• Maximum time between doses should not exceed 12 hours to maintain therapeutic levels 1
• Gabapentin has nonlinear pharmacokinetics, meaning higher doses do not produce proportional increases in blood levels due to saturable intestinal absorption 2
• An adequate therapeutic trial requires 3-8 weeks for titration plus 2 weeks at maximum tolerated dose before declaring treatment failure 2

Mandatory Dose Reductions

Renal impairment requires mandatory dose adjustment, as gabapentin is eliminated primarily by renal excretion 2, 1:

• CrCl ≥60 mL/min: Maximum 3600 mg/day (1200 mg three times daily) 1
• CrCl 30-59 mL/min: Maximum 1400 mg/day (700 mg twice daily) 1
• CrCl 15-29 mL/min: Maximum 700 mg/day (700 mg once daily) 1
• CrCl <15 mL/min: Maximum 300 mg/day (300 mg once daily) 1
• Hemodialysis patients: Maintenance dose based on CrCl plus supplemental 125-350 mg post-dialysis dose 1

Special Population Adjustments

• Elderly patients require dose selection based on creatinine clearance values, as they are more likely to have decreased renal function 1
• Start elderly or medically frail patients at lower doses (100 mg at bedtime) with slower titration every 3-7 days to reduce fall risk from dizziness 2

Common Pitfall to Avoid

• Never use once-daily or twice-daily dosing for standard gabapentin at any dose level, as three-times-daily administration is essential for efficacy due to saturable absorption in the proximal small intestine 2
• Do not abruptly discontinue gabapentin at any dose; taper gradually over at least 1 week to avoid withdrawal symptoms 1
• Do not rush to maximum dose—allow full titration period and adequate trial duration before increasing beyond 1800 mg/day 2