RESEARCH MONOGRAPH · KDC-MN-252
Gabapentin
Gabapentin (Neurontin) is the older sibling of pregabalin from Parke-Davis, FDA-approved in 1993, and it works by the same mechanism: binding the alpha-2-delta subunit of voltage-gated calcium channels, with no actual effect on GABA receptors despite the misleading name. The big practical difference from pregabalin is dose-response: gabapentin's intestinal absorption saturates, so doubling the dose does not double the blood level, which makes high doses inefficient. Approved for postherpetic neuralgia and partial seizures, with massive off-label use for anxiety, sleep, alcohol withdrawal, restless legs, and chronic pain. The Pfizer off-label marketing campaign that drove its sales in the 1990s was the subject of a landmark fraud settlement. Abuse potential is real but lower than pregabalin's. Not stocked by Kodiac. This monograph is provided for research and educational reference.
Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.
GABA analog calcium channel ligand
A GABA analog binding the alpha-2-delta subunit of voltage-gated calcium channels; the structural and clinical predecessor to pregabalin.
Abstract
Gabapentin (1-(aminomethyl)cyclohexaneacetic acid; CAS 60142-96-3; molecular formula C9H17NO2; molecular weight 171.24) is a GABA analog developed at Parke-Davis (Pfizer) in the 1980s and approved by the FDA in 1993 under the trade name Neurontin. Mechanism mirrors pregabalin: binding to the alpha-2-delta-1 subunit of voltage-gated calcium channels (Ki approximately 80 nM, weaker than pregabalin), reducing presynaptic neurotransmitter release. No direct GABA receptor activity. Plasma half-life is 5 to 7 hours. Distinguished from pregabalin by saturable absorption: oral bioavailability ranges from 80 percent at 100 mg to 27 percent at 1600 mg, producing nonlinear dose-response and unpredictable individual responses at higher doses. Approved for postherpetic neuralgia and partial-onset seizures (adjunctive); off-label use is extensive (anxiety, alcohol withdrawal, restless legs syndrome, hot flashes, hiccups, neuropathic pain of all causes, migraine prophylaxis). The compound has been the subject of extensive off-label promotion litigation and is now scheduled in some US states reflecting abuse potential. Used as the canonical alpha-2-delta-1 calcium channel ligand and a reference compound in seizure pharmacology.
Mechanism of action
Alpha-2-delta-1 subunit binding (weaker than pregabalin); saturable absorption produces nonlinear dose-response.
Reported research dose ranges
Clinical 300 to 3600 mg per oral administration daily, in divided doses. Rodent studies 30 to 300 mg/kg/day.
References
- Sills GJ. The mechanisms of action of gabapentin and pregabalin. Curr Opin Pharmacol 2006.
- Maneuf YP, et al. Gabapentin and the alpha-2-delta auxiliary subunit. Pharmacol Ther 2003.
- Mack A. Examination of the evidence for off-label use of gabapentin. J Manag Care Pharm 2003.
Read the full monograph
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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.