Gabapentin

Gabapentin
Clinical data
Trade names	Neurontin, others
Other names	CI-945; GOE-3450; DM-1796 (Gralise)
AHFS/Drugs.com	Monograph
MedlinePlus	a694007
License data	US DailyMed: Gabapentin;
Pregnancy; category	AU: B1;
Dependence; liability	Physical: High; Psychological: Moderate
Addiction; liability	Low
Routes of; administration	By mouth
Drug class	Prototypical Gabapentinoid; Anticonvulsant; GABA analog;
ATC code	N02BF01 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); BR: Class C1 (Other controlled substances); CA: ℞-only; UK: Class C; US: Schedule V controlled substance (Select States); SE: Rx-only; In general: Prescription only; ;
Pharmacokinetic data
Bioavailability	27–60% (inversely proportional to dose; a high-fat meal also increases bioavailability)
Protein binding	Less than 3%
Metabolism	Not significantly metabolized
Onset of action	2-3 hours
Elimination half-life	5 to 7 hours
Excretion	Kidney
Identifiers
	IUPAC name 2-[1-(Aminomethyl)cyclohexyl]acetic acid;
CAS Number	60142-96-3;
PubChem CID	3446;
IUPHAR/BPS	5483;
DrugBank	DB00996;
ChemSpider	3328;
UNII	6CW7F3G59X;
KEGG	D00332;
ChEBI	CHEBI:42797;
ChEMBL	ChEMBL940;
PDB ligand	GBN (PDBe, RCSB PDB);
CompTox Dashboard (EPA)	DTXSID0020074 ;
ECHA InfoCard	100.056.415
Chemical and physical data
Formula	C9H17NO2
Molar mass	171.240 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C(O)CC1(CN)CCCCC1;
	InChI InChI=1S/C9H17NO2/c10-7-9(6-8(11)12)4-2-1-3-5-9/h1-7,10H2,(H,11,12); Key:UGJMXCAKCUNAIE-UHFFFAOYSA-N;

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 the inhibitory neurotransmitter, 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 binds to α2δ subunits to modulate calcium channel function and neurotransmitter release, weakly affects glutamate signaling pathways, and does not act on GABA receptors. Sleepiness and dizziness are the most common side effects. Serious side effects include extreme sedation, respiratory depression and allergic reactions. In December 2008, the US Food and Drug Administration issued a class-wide warning for gabapentinoids 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 45 million 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.