gabapentin
n. a drug used for the treatment of seizures (see anticonvulsant) and for the relief of pain associated with shingles (see herpetic neuralgia). Its mechanism of action is unknown: It is a chemical analog of the neurotransmitter gamma-aminobutyric acid (GABA) that is a potent ligand at alpha 2 delta sites on voltage-gated N and P/Q channels. Gabapentin is currently being investigated for the treatment of certain other disorders, including restless legs syndrome, anxiety disorders, and fibromyalgia, but it is largely discredited as a mood stabilizer for bipolar disorder. Side effects are primarily sedation, dizziness, ataxia, and fatigue; abrupt withdrawal may precipitate seizures. U.S. trade name: Neurontin.