Maximum Dose of Gabapentin

The maximum daily dose of gabapentin is 3600 mg per day, typically divided into three doses. 1, 2

General Dosing Guidelines

Gabapentin is typically initiated at low doses (300 mg) and gradually titrated to minimize side effects 1
For most indications, the effective dose range is between 1800-3600 mg/day in divided doses 1
The maximum time between doses should not exceed 12 hours to maintain therapeutic levels 2
Doses should be divided into three daily administrations for optimal effect and tolerability 1, 2

For postherpetic neuralgia:
- Maximum daily dose is 3600 mg/day 2
- Clinical studies demonstrated efficacy across 1800-3600 mg/day, with no additional benefit proven above 1800 mg/day 2
For epilepsy with partial onset seizures:
- In patients 12 years and older, doses up to 2400 mg/day are well-tolerated in long-term studies 2
- Doses of 3600 mg/day have been administered for shorter durations with good tolerability 2
For neuropathic pain:
- Maximum daily dose is 3600 mg/day in three divided doses 1
- Maximum single dose is generally 1200 mg 1
- For unexplained chronic cough, maximum tolerable daily dose is 1800 mg in two divided doses 1

Renal impairment: Dosage adjustment is required based on creatinine clearance 2
- For CrCl ≥60 mL/min: 900-3600 mg/day (300-1200 mg TID)
- For CrCl 30-59 mL/min: 400-1400 mg/day (200-700 mg BID)
- For CrCl 15-29 mL/min: 200-700 mg/day (200-700 mg QD)
- For CrCl <15 mL/min: 100-300 mg/day (100-300 mg QD)
Elderly patients:
- Lower doses may be more appropriate due to potential decreased renal function 1, 2
- Dose should be adjusted based on creatinine clearance values 2
- Effective doses may be lower than standard ranges due to increased sensitivity to side effects 1

Initial dosing should start at 100-300 mg at bedtime or 100-300 mg three times daily 1
Dose increases should be gradual: 100-300 mg every 1-7 days as tolerated 1
An adequate trial of gabapentin for pain can require 2 months or more to determine full efficacy 1
If gabapentin is discontinued, it should be tapered gradually over a minimum of 1 week to avoid withdrawal symptoms 2

Underdosing: Many patients are maintained on subtherapeutic doses that don't provide adequate symptom control 3
Too-rapid titration: Starting with higher doses or titrating too quickly can lead to increased side effects and poor tolerability 1
Inadequate trial duration: Pain relief may require extended treatment periods; trials should be at least 2 months before determining lack of efficacy 1
Renal function monitoring: Failure to adjust dosing based on renal function can lead to toxicity 2
Divided dosing importance: Administering the total daily dose at once rather than divided can increase side effects and reduce efficacy 2