The precise mechanisms by which gabapentin produces its analgesic and antiepileptic actions are unknown. Gabapentin is structurally related to the neurotransmitter gamma-aminobutyric acid (GABA) but has no effect on GABA binding, uptake, or degradation. In vitro studies have shown that gabapentin binds with high-affinity to the α2δ subunit of voltage-activated calcium channels; however, the relationship of this binding to the therapeutic effects of gabapentin is unknown.

NEURONTIN® is indicated for: Management of postherpetic neuralgia in adults. Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy.

Postherpetic Neuralgia: Dose can be titrated up as needed to a dose of 1800 mg/day. Day 1: Single 300 mg dose. Day 2: 600 mg/day (i.e., 300 mg two times a day). Day 3: 900 mg/day (i.e., 300 mg three times a day). Epilepsy with Partial Onset Seizures: Patients 12 years of age and older: starting dose is 300 mg three times daily; may be titrated up to 600 mg three times daily. Patients 3 to 11 years of age: starting dose range is 10 to 15 mg/kg/day, given in three divided doses; recommended dose in patients 3 to 4 years of age is 40 mg/kg/day, given in three divided doses; the recommended dose in patients 5 to 11 years of age is 25 to 35 mg/kg/day, given in three divided doses. The recommended dose is reached by upward titration over a period of approximately 3 days. Dose should be adjusted in patients with reduced renal function.

Most common adverse reactions (incidence ≥8% and at least twice that for placebo) were: Postherpetic neuralgia: Dizziness, somnolence, and peripheral edema. Epilepsy in patients >12 years of age: Somnolence, dizziness, ataxia, fatigue, and nystagmus. Epilepsy in patients 3 to 12 years of age: Viral infection, fever, nausea and/or vomiting, somnolence, and hostility.

NEURONTIN is contraindicated in patients who have demonstrated hypersensitivity to the drug or its ingredients.

Drug Reaction with Eosinophilia and Systemic Symptoms (Multiorgan hypersensitivity): Discontinue if alternative etiology is not established. Anaphylaxis and Angioedema: Discontinue and evaluate patient immediately. Driving Impairment; Somnolence/Sedation and Dizziness: Warn patients not to drive until they have gained sufficient experience to assess whether their ability to drive or operate heavy machinery will be impaired. Increased seizure frequency may occur in patients with seizure disorders if NEURONTIN is abruptly discontinued. Suicidal Behavior and Ideation: Monitor for suicidal thoughts/behavior. Respiratory Depression: May occur with NEURONTIN when used with concomitant central nervous system (CNS) depressants, including opioids, or in the setting of underlying respiratory impairment. Monitor patients and adjust dosage as appropriate. Neuropsychiatric Adverse Reactions in Children 3 to 12 Years of Age: Monitor for such events.