Class: Gamma Aminobutyric Acid, Anticonvulsant
Dosage Forms. Capsule: 100 mg, 300 mg, 400 mg; Tablet: 300 mg, 600 mg, 800 mg; Solution: 250 mg/5 mL
Common FDA Label Indication, Dosing, and Titration.
1. Partial seizure, adjunct: ≥12 y: Initial, 300 mg po tid; may increase to 1800 mg/d in 3 divided doses (max 2400-3600 mg/d); 3-12 y: Initial, 10-15 mg/kg/d in 3 divided doses; maintenance (3-4 y): titrate over 3 d to 40 mg/kg/d in 3 divided doses; (5-12 y): titrate upward over 3 d to 25-35 mg/kg/d in 3 divided doses
2. Postherpetic neuralgia: Adults, 300 mg po on day 1, 300 mg bid on day 2, 300 mg tid on day 3; may increase dose to 1800 mg/d in 3 divided doses
1. Diabetic peripheral neuropathy: Adults, 900-3600 mg/d
2. Restless leg syndrome: 300 mg po qhs
MOA. Gabapentin is a cyclohexane compound that is structurally related to GABA; its mechanism of action is not known. Gabapentin does not interact with GABA receptors or alter the formation, release, degradation, or reuptake of GABA.
Drug Characteristics: Gabapentin
Medication Safety Issues: Gabapentin
Drug Interactions: Gabapentin
Adverse Reactions: Gabapentin
Efficacy Monitoring Parameters. Reduction in seizure frequency or relief of pain associated with postherpetic neuralgia.
Toxicity Monitoring Parameters. Emergence or worsening of depression, suicidality, and/or any unusual behavioral or mood changes (anxiety, agitation, hostility, mania, and hypomania).
Key Patient Counseling Points. Patient should avoid activities requiring mental alertness or coordination until drug effects are realized, as drug may cause dizziness and somnolence. Report worsening depression, suicidal ideation, or unusual changes in behavior. Avoid sudden discontinuation of drug, as this may precipitate status epilepticus. Wait 2 h after antacid before taking gabapentin.
Clinical Pearls. Use in renally compromised patients <12 y of age has not been studied. Dosage interval should not exceed 12 h. Gabapentin dose reductions, discontinuation, or substitutions with alternative medications should be performed gradually over a min of 1 wk. Medication guide required at dispensing.