Maximum Daily Dose of Gabapentin
The maximum total daily dose of gabapentin is 3600 mg/day, administered as 1200 mg three times daily, with mandatory dose reduction required in renal impairment based on creatinine clearance. 1
Standard Maximum Dosing in Adults with Normal Renal Function
The FDA-approved maximum dose is 3600 mg/day (1200 mg three times daily), which has been well tolerated in clinical studies for both postherpetic neuralgia and epilepsy 1.
Doses must be administered three times daily with a maximum interval of 12 hours between doses, due to gabapentin's saturable, nonlinear absorption pharmacokinetics 1, 2.
While doses up to 4800 mg/day have been administered to small numbers of patients for short durations and were well tolerated, this exceeds the FDA-approved maximum and is not routinely recommended 1.
Dose Adjustments in Renal Impairment
Mandatory dose reduction is required based on creatinine clearance, as gabapentin is eliminated primarily by renal excretion 1, 2:
| Creatinine Clearance (mL/min) | Maximum Daily Dose | Dosing Frequency |
|---|---|---|
| ≥ 60 | 3600 mg | 300–1200 mg TID |
| 30–59 | 1400 mg | 200–700 mg BID |
| 15–29 | 700 mg | 200–700 mg once daily |
| < 15 | 300 mg | 100–300 mg once daily |
Calculate creatinine clearance using the Cockcroft-Gault equation before initiating therapy, particularly in elderly patients who invariably have reduced renal function despite normal serum creatinine 1, 3.
Patients on hemodialysis require supplemental post-dialysis dosing of 125–350 mg after each 4-hour hemodialysis session, in addition to maintenance doses based on creatinine clearance 1.
Special Considerations for Elderly Patients
Elderly patients require dose selection based on creatinine clearance values, not just age, because age-related decline in renal function is often masked by normal serum creatinine due to reduced muscle mass 1, 3.
Start at lower doses (100–200 mg/day) with slower titration (increases every 3–7 days or longer) to minimize fall risk from dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (9%) 2, 3.
Therapeutic Dose Range for Neuropathic Pain
The minimum effective dose for neuropathic pain is 1800 mg/day (600 mg three times daily), with the target therapeutic range being 1800–3600 mg/day in three divided doses 2, 4.
Doses of 1800–3600 mg/day provide moderate-quality evidence for efficacy, with 32–38% of patients achieving at least 50% pain reduction versus 17–21% with placebo in postherpetic neuralgia and painful diabetic neuropathy 2, 4.
Critical Pitfalls to Avoid
Never use once-daily or twice-daily dosing for standard gabapentin at therapeutic doses in patients with normal renal function—three times daily administration is mandatory due to saturable absorption 2, 1.
Do not assume normal renal function in elderly patients based on serum creatinine alone—always calculate creatinine clearance before prescribing 3.
Avoid abrupt discontinuation—taper gradually over a minimum of 1 week to prevent withdrawal symptoms 1, 2.
Do not declare treatment failure before completing a full 2-month trial (3–8 weeks for titration plus 2 weeks at maximum tolerated dose), as efficacy develops gradually over several weeks 2, 3.