Gabapentin

Gamma-aminobutyric acid analog

Gabapentin, sold under the brand name Neurontin among others, is an anticonvulsant medication used to treat neuropathic pain (postherpetic neuralgia) and partial seizures of epilepsy. Gabapentin is a central nervous system (CNS) depressant and derivative of GABA. It is used for the treatment of neuropathic pain caused by diabetic neuropathy, postherpetic neuralgia, and central pain. It is moderately effective: about 30–40% of those given gabapentin for diabetic neuropathy or postherpetic neuralgia have a meaningful benefit.

Gabapentin acts by decreasing activity of the α2δ-1 protein, coded by the CACNA2D1 gene, first known as an auxiliary subunit of voltage-gated calcium channels. By binding to α2δ-1, gabapentin reduces the release of excitatory neurotransmitters (primarily glutamate) and as a result, reduces excess excitation of neuronal networks in the spinal cord and brain. Sleepiness and dizziness are the most common side effects. Serious side effects include respiratory depression and allergic reactions. On December 16, 2008, the FDA issued gabapentin a class warning for an increased risk of suicide. Approximately two years after this pronouncement, a pharmacoepidemiologic study was conducted that showed there was no outstanding difference in suicide attempt rates between pre- and post- gabapentin prescription groups.

Gabapentin was first approved for use in the United Kingdom in 1993. It has been available as a generic medication in the United States since 2004. It is the first of several other drugs that are similar in structure and mechanism, called gabapentinoids. In 2023, it was the ninth most commonly prescribed medication in the United States, with more than 45million prescriptions. During the 1990s, Parke-Davis, a subsidiary of Pfizer, used several illegal techniques to encourage physicians in the United States to prescribe gabapentin for unapproved uses. They have paid out millions of dollars to settle lawsuits regarding these activities.