What is the maximum dose of gabapentin (Neurontin)?

Maximum Dose of Gabapentin

The maximum dose of gabapentin is 3600 mg per day in divided doses, which is the conventional upper limit for adults with normal renal function. 1, 2

General Dosing Guidelines

• The effective dosage range of gabapentin is 900-3600 mg daily in divided doses (typically 2-3 administrations per day) 1
• For postherpetic neuralgia, while efficacy was demonstrated across doses from 1800-3600 mg/day, the FDA label notes that additional benefit of using doses greater than 1800 mg/day was not demonstrated in clinical studies 2
• For epilepsy with partial onset seizures in patients 12 years and older, dosages up to 2400 mg/day have been well tolerated in long-term clinical studies, though doses of 3600 mg/day have also been administered for shorter durations 2

Administration Schedule

• The total daily dose should be divided into three administrations per day, especially at higher doses, to maintain therapeutic levels 1
• The maximum time between doses should not exceed 12 hours 2
• When taking gabapentin for neuropathic pain, the maximum single dose is generally 1200 mg, as part of the maximum daily dose of 3600 mg divided into three doses 3

Dose Titration

• Treatment should be initiated at low dosages (100-300 mg at bedtime) and gradually titrated to minimize side effects 1, 3
• Dose increments of 50-100% every few days are recommended until pain relief is achieved 1
• Doses should be increased until analgesic effect is achieved, side effects become unmanageable, or the conventional maximum dose of 3600 mg/day is reached 1

Special Populations

Renal Impairment

• Dose adjustment is required for patients with compromised renal function 1, 2
• For patients with creatinine clearance <15 mL/min, the daily dose should be reduced in proportion to creatinine clearance 2
• Specific dosing recommendations based on creatinine clearance:
  • ≥60 mL/min: 900-3600 mg/day (300-1200 mg TID)

  • 30-59 mL/min: 400-1400 mg/day (200-700 mg BID)

  • 15-29 mL/min: 200-700 mg/day (100-700 mg QD)

  • 15 mL/min or less: 100-300 mg/day (100-300 mg QD) 2

Elderly Patients

• Lower doses and slower titration are recommended for elderly patients or those who are medically frail 1, 3
• Elderly patients are more likely to have decreased renal function, so dose should be adjusted based on creatinine clearance values 2
• The effective dose in older adults may be lower than standard ranges due to increased sensitivity to side effects 3

Common Adverse Effects

• Dizziness (19%) and somnolence (14%) are the most common adverse effects 4, 5
• Other common adverse effects include peripheral edema (7%) and gait disturbance (9%) 5
• Side effects can be reduced by starting with lower dosages and titrating cautiously 3
• Adverse events occurred significantly more often with gabapentin (62% of patients) compared to placebo 5

Clinical Pearls

• An adequate trial of gabapentin for pain can require 2 months or more to determine full efficacy 3
• For neuropathic pain, treatment should be initiated at low dosages with gradual titration until pain relief, dose-limiting adverse effects, or the maximum dose of 3600 mg/day in 3 divided doses is reached 3, 6
• Response to gabapentin may vary among different types of neuropathic pain and individual patients 1
• Patient education should emphasize the trial and error nature of treatment to prevent discouragement 1