Section 01 · Monograph
Gabapentin
Reviewed Nov 2026FDA label
NeurontinGabapentinoid
- Forms
- Cap: 100, 300, 400mg | Tab: 600, 800mg | Sol: 250mg/5mL
- Dose
- 900-3600mg/day
- MOA
- Binds α2δ Ca2+ channel subunit
Indications
- Postherpetic neuralgiaFDA-labeled
- Adjunctive therapy for partial-onset seizures, age 3+FDA-labeled
Off-Label Uses
- Diabetic peripheral neuropathy and other neuropathic pain syndromesOff-label
- Restless legs syndrome (as gabapentin enacarbil, a related prodrug, is FDA-approved for this)Off-label
- Adjunctive anxiety/alcohol withdrawal management in select settingsOff-label
Mechanism of Action
- Structural analog of GABA but does not act directly on GABA receptors
- Binds the alpha-2-delta subunit of voltage-gated calcium channels
- Reduces calcium influx at nerve terminals, decreasing release of excitatory neurotransmitters (glutamate, substance P, norepinephrine) involved in pain signaling and seizure activity
Full Dosing
Adult / usual
- Neuropathic pain: start 300mg at bedtime or TID, titrate over days to weeks to 900-3600mg/day divided TID
- Supplemental dose recommended after hemodialysis sessions
Renal
- Requires renal dose adjustment based on CrCl — significant reduction needed in renal impairment
Pediatric
- Pediatric seizure dosing (3-12 years): weight-based per label
Contraindications
- Known hypersensitivity to gabapentin or its ingredients
Drug Interactions
- CNS depressants (opioids, benzodiazepines, alcohol) — additive sedation and respiratory depression risk, especially in elderly or respiratory-compromised patients (FDA warning)
- Antacids may reduce absorption — separate dosing by at least 2 hours
Adverse Effects
- Common: somnolence, dizziness, ataxia, peripheral edema, weight gain
- FDA warning: risk of respiratory depression when combined with opioids or in patients with compromised respiratory function (COPD, elderly)
- Potential for misuse, particularly in combination with opioids
Monitoring Parameters
- Renal function for dosing
- Respiratory status if combined with other CNS depressants
- Signs of misuse in at-risk populations
Pregnancy & Lactation
- Data suggest a possible increased risk of preterm birth and small-for-gestational-age infants
- Individualize risk versus benefit