How it's calculated
Gabapentin dosing is titration-based and varies by indication rather than a single formula. This tool returns the standard adult (or paediatric, for epilepsy) titration schedule for the selected indication, plus a renal dose adjustment if a creatinine clearance is entered — gabapentin is cleared entirely by the kidneys with no hepatic metabolism.
Renal dose adjustment (all indications)
| CrCl (mL/min) | Total daily dose | Regimen |
|---|---|---|
| ≥ 60 | 900-3600 mg/day | 3 divided doses |
| 30-59 | 400-1400 mg/day | 2 divided doses |
| 15-29 | 200-700 mg/day | Once daily |
| < 15 | 100-300 mg/day | Once daily |
| Haemodialysis | 200-300 mg | After each 4-hour HD session (loading dose 300-400 mg for HD-naive patients) |
Clinical use
- Available strengths (capsule/tablet): 100 mg, 300 mg, 400 mg capsules; 600 mg and 800 mg tablets; also available as an oral solution for paediatric or dose-titration flexibility.
- Epilepsy dosing is the most extensively studied and has the clearest titration schedule; anxiety is an off-label use with a comparatively limited evidence base and less standardised dosing.
- Restless Legs Syndrome is typically dosed once daily in the evening rather than divided through the day, since symptoms are predominantly evening/nighttime.
- Because gabapentin is renally cleared, dose adjustment by creatinine clearance applies across all indications, not just epilepsy — always reassess the dose if renal function changes during treatment.
Frequently asked questions
Does gabapentin dosing differ by indication?
Yes — epilepsy and postherpetic neuralgia have well-established titration schedules (starting 300 mg and increasing over 3 days), while restless legs syndrome is typically dosed once in the evening, and anxiety is an off-label use with less standardised dosing.
Why does renal function matter so much for gabapentin?
Gabapentin is eliminated almost entirely unchanged by the kidneys with no hepatic metabolism, so reduced renal clearance leads directly to drug accumulation — dose reduction by creatinine clearance is required across all indications.
Can gabapentin be stopped abruptly?
It's not recommended — abrupt discontinuation after regular use can cause withdrawal symptoms and, in patients with epilepsy, rebound seizures. Taper the dose when stopping.
What is the paediatric dose for epilepsy?
Typically started at 10-15 mg/kg/day divided into three doses and titrated over about 3 days to a usual effective dose of roughly 25-40 mg/kg/day divided three times daily for ages 3-12 — confirm the exact age-banded target against current paediatric references.
References
- Gabapentin (Neurontin) FDA Prescribing Information — Renal Impairment Dosing Table.
- Backonja M, Glanzman RL. Gabapentin dosing for neuropathic pain: evidence from randomized, placebo-controlled clinical trials. Clin Ther. 2003;25(1):81-104.
- Allen R, Chen C, Soaita A, et al. A randomized, double-blind, placebo-controlled trial of gabapentin enacarbil in subjects with restless legs syndrome. Sleep Med. 2010;11(6):512-519.