Gabapentin Dosing in Adults

1. Epilepsy (adjunctive therapy for focal/partial seizures)

• Start: 300 mg on day 1, titrating up over the first few days (or per some regimens, starting at 900 mg/day in 3 divided doses)
• Usual maintenance: 900-1800 mg/day in 3 divided doses
• Maximum: up to 3600 mg/day if higher doses are needed for seizure control
• Source: Goodman & Gilman's Pharmacological Basis of Therapeutics; Katzung's Basic and Clinical Pharmacology, 16th Ed.

2. Neuropathic Pain (postherpetic neuralgia, diabetic neuropathy, other neuropathic pain syndromes)

• Start: 100-300 mg at bedtime
• Titrate carefully upward over days to weeks (commonly to 3 times daily dosing)
• Effective/maintenance range: up to 3600 mg/day, well tolerated in most patients when titrated slowly
• Gabapentin is considered a first-line co-analgesic for neuropathic pain, particularly favored in elderly and medically ill patients because of its favorable safety profile and low drug-interaction potential
• Source: Bradley and Daroff's Neurology in Clinical Practice; Kaplan & Sadock's Comprehensive Textbook of Psychiatry (typical regimens use doses "at least" effective at creatinine clearance ≥60 mL/min, with reduction based on renal function)

3. Uremic Pruritus (dialysis patients) - special population dosing

• 100-300 mg given thrice weekly, after each dialysis session (not daily) - a much lower dose because gabapentin is renally cleared and accumulates in ESKD, risking neurotoxicity
• Source: Comprehensive Clinical Nephrology, 7th Edition

Renal Impairment - critical adjustment

Key practical points

• Divide total daily dose into 3 doses/day for most indications (except pruritus, which is post-dialysis dosing).
• Titrate slowly to minimize dizziness, somnolence, and unsteadiness - the most common adverse effects.
• Always individualize based on renal function, indication, and tolerability rather than jumping straight to high doses.