What is the maximum recommended dose for gabapentin (Neurontin)?

Maximum Dose for Gabapentin

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

FDA-Approved Maximum Dosing

• The FDA label explicitly states that doses of 3600 mg/day have been administered and well tolerated, though for shorter durations 1
• For postherpetic neuralgia specifically, the FDA notes that efficacy was demonstrated over a range of 1800-3600 mg/day, though additional benefit above 1800 mg/day was not clearly demonstrated in pivotal trials 1
• For epilepsy in adults, dosages up to 2400 mg/day have been well tolerated in long-term studies, with 3600 mg/day administered to smaller patient numbers 1

Guideline Society Recommendations

• The American Academy of Neurology and National Comprehensive Cancer Network consistently recommend a target therapeutic dose range of 1800-3600 mg/day in three divided doses for neuropathic pain 2
• The maximum single dose should not exceed 1200 mg due to gabapentin's saturable absorption pharmacokinetics 3
• Three-times-daily dosing is essential—once or twice daily administration is not recommended for standard gabapentin formulations because of nonlinear, saturable absorption 2

Special Population Adjustments

Renal Impairment

• Mandatory dose reduction is required based on creatinine clearance, as gabapentin is eliminated primarily by renal excretion 2, 1
• For creatinine clearance ≥60 mL/min: maximum 3600 mg/day (1200 mg three times daily) 1
• For creatinine clearance 30-59 mL/min: maximum 1400 mg/day (700 mg twice daily) 1
• For creatinine clearance 15-29 mL/min: maximum 700 mg/day (700 mg once daily) 1
• For creatinine clearance <15 mL/min: maximum 300 mg/day (300 mg once daily) 1
• Hemodialysis patients require supplemental post-dialysis dosing of 125-350 mg after each 4-hour session 1

Elderly Patients

• The American Geriatrics Society recommends lower doses in older adults due to decreased renal function and increased sensitivity to side effects 3
• Dose selection must be adjusted based on creatinine clearance values, which should be calculated using the Cockcroft-Gault equation 1

Critical Dosing Considerations

• The maximum time interval between doses must not exceed 12 hours to maintain therapeutic levels 1
• An adequate therapeutic trial requires 2 months or more—efficacy develops gradually over several weeks, so treatment should not be declared a failure prematurely 2, 3
• The minimum effective dose for most neuropathic pain conditions is 1800 mg/day (600 mg three times daily), with many patients requiring the full 3600 mg/day for optimal pain relief 2

Common Pitfalls to Avoid

• Do not use once-daily or twice-daily dosing for standard gabapentin—three times daily administration is essential due to saturable absorption 2
• Do not rush titration in elderly patients, as this increases fall risk from dizziness 2
• Do not discontinue abruptly—taper gradually over at least 1 week to avoid withdrawal symptoms 1
• Do not exceed 12-hour intervals between doses, as this compromises therapeutic efficacy 1