Gabapentin: A Ca2+ channel α2-δ ligand far beyond epilepsy therapy

Gabapentin is an antiepileptic drug (AED) by design expected to mimic the action of the neurotransmitter γ-aminobutyric acid (GABA). However, its principal proposed mechanism of action is the interaction with the α2-δ subunit of L-type voltage-regulated calcium channels. Gabapentin possesses several desirable pharmacokinetic properties, along with few drug interactions, particularly with other AEDs. These properties make it a well-tolerated drug, with the most commonly reported adverse events being somnolence and dizziness. Gabapentin is one of the new first-generation AEDs that expanded its use into a broad range of neurologic and psychiatric disorders shortly after it was licensed in 1993 for use in drug-resistant partial epilepsy with or without secondary generalization. Nowadays, most worldwide prescriptions for gabapentin are for conditions other than epilepsy, especially the treatment of chronic pain of different etiologies. This article will review the pharmacology, mechanism of action, drug interactions and adverse effects of gabapentin. In addition, the clinical trial data, cost analysis and recommended schedule of administration, are also reviewed.