gabapentine

Gabapentin, marketed under brand names such as Neurontin and Gralise, is an anticonvulsant medication used to treat certain types of seizures and neuropathic pain. The spelling gabapentine is occasionally encountered in nonstandard texts, but gabapentin is the correct name; there is no widely recognized drug with the name gabapentine in contemporary medical references. Gabapentin is a structural analogue of the neurotransmitter GABA but does not bind to GABA receptors.

Gabapentin is approved as an adjunctive therapy for partial-onset seizures in adults and children older than 3 years. It is also approved for the treatment of postherpetic neuralgia and, in some regions, for other neuropathic pain conditions such as painful diabetic neuropathy and central neuropathic pain. It is used off-label for anxiety disorders, fibromyalgia, migraine prophylaxis, and restless legs syndrome in some settings.

Mechanism: It binds to the alpha-2-delta subunit of voltage-gated calcium channels, reducing excitatory neurotransmitter release. This action is not mediated by GABA receptors, despite structural similarity to GABA.

Gabapentin is administered orally and is absorbed by the gut with about 60 percent bioavailability that decreases as dose increases. It is eliminated unchanged by the kidneys; half-life is about 5 to 7 hours in people with normal renal function, necessitating multiple daily doses and dose adjustment in renal impairment.

Common side effects include dizziness, somnolence, fatigue, and peripheral edema. At high doses, coordination problems and cognitive impairment may occur. There is a risk of mood changes and suicidal thoughts. Gabapentin has limited liver metabolism and few drug interactions, but concurrent use with alcohol or central nervous system depressants can enhance sedation. It is categorized as pregnancy category C, with uncertain risk in humans.

Since its approval in the 1990s, gabapentin has become widely available as a generic medication.