Gabapentin
Neurontin · Gralise
Gabapentinoid (Calcium Channel Alpha-2-Delta Ligand)Generic availableTDM data
The precise mechanisms by which gabapentin produces its analgesic and antiepileptic actions are unknown. Gabapentin is structurally related to the neurotransmitter gamma-aminobutyric acid (GABA) but has no effect on GABA binding, uptake, or degradation. In vitro studies have shown that gabapentin binds with high-affinity to the α2δ subunit of voltage-activated calcium channels; however, the relationship of this binding to the therapeutic effects of gabapentin is unknown.
Compare Gabapentin →FDA-Approved Indications
- Postherpetic neuralgia (adults)
- Partial-onset seizures — adjunct (adults; pediatric 3+ years)
Common Off-Label Uses
- Generalized anxiety disorder
- Social anxiety disorder
- Alcohol use disorder
- Restless legs syndrome
- Hot flashes
- Insomnia
- Neuropathic pain (off-label in some contexts)
What Sets This Drug Apart
- No FDA-approved psychiatric indication despite widespread off-label use for anxiety, insomnia, and neuropathic pain
- Zero CYP metabolism and entirely renally cleared — cleanest drug-drug interaction profile of any psychotropic; ideal for polypharmacy patients
- Non-linear pharmacokinetics: bioavailability decreases at higher doses (60% at 900 mg, 27% at 4800 mg) due to saturable L-amino acid transport
- Misuse and diversion signal despite lack of federal scheduling; some states have added it to controlled substance monitoring programs
- Dose reduction required in renal impairment; no hepatic adjustment needed