Gabapentin is a structural analog of Gamma-Aminobutyric Acid (GABA). Its mechanism of action is unknown. Unexpectedly, it does not interact with GABA receptors.

Specific Dosages

Dosing: Adult

Anticonvulsant: Oral:

Initial: 300 mg 3 times/day, if necessary the dose may be increased up to 1800 mg/day

Maintenance: 900-1800 mg/day administered in 3 divided doses; doses of up to 2400 mg/day have been tolerated in long-term clinical studies; up to 3600 mg/day has been tolerated in short-term studies

Note: If gabapentin is discontinued or if another anticonvulsant is added to therapy, it should be done slowly over a minimum of 1 week.

Chronic pain (unlabeled use): Oral: 300-1800 mg/day given in 3 divided doses has been the most common dosage range

Diabetic neuropathy (unlabeled use): Oral: 900-3600 mg/day (Bril, 2011)

Postoperative pain (unlabeled use): 300-1200 mg 1-2 hours before surgery

Postherpetic neuralgia: Day 1: 300 mg, Day 2: 300 mg twice daily, Day 3: 300 mg 3 times/day; dose may be titrated as needed for pain relief (range: 1800-3600 mg/day, daily doses >1800 mg do not generally show greater benefit)

Restless legs syndrome (RLS) (unlabeled use): Oral: Initial: 300 mg once daily 2 hours before bedtime. Doses ≥600 mg/day have been given in 2 divided doses (late afternoon and 2 hours before bedtime). Dose may be titrated every 2 weeks until symptom relief achieved (range: 300-1800 mg/day). Suggested maintenance dosing schedule: One-third of total daily dose given at 12 pm, remaining two-thirds total daily dose given at 8 pm. (Garcia-Borreguero, 2002; Happe, 2003; Saletu, 2010; Vignatelli, 2006)

Vasomotor symptoms associated with menopause (unlabeled use; Butt, 2008): 300 mg 3 times/day

Dosing: Pediatric

(For additional information see "Gabapentin: Pediatric drug information")

Anticonvulsant: Oral

Children 3-12 years: Initial: 10-15 mg/kg/day in 3 divided doses; titrate to effective dose over ~3 days; dosages of up to 50 mg/kg/day have been tolerated in clinical studies

Children 3-4 years: Effective dose: 40 mg/kg/day in 3 divided doses

Children 5-12 years: Effective dose: 25-35 mg/kg/day in 3 divided doses

Children >12 years: Refer to adult dosing.

Note: If gabapentin is discontinued or if another anticonvulsant is added to therapy, it should be done slowly over a minimum of 1 week

Dosing: Geriatric

Studies in elderly patients have shown a decrease in clearance as age increases. This is most likely due to age-related decreases in renal function; dose reductions may be needed