Gabapentin (Neurontin)

Class

Anticonvulsant, GABA analog

Mechanism

Modulates voltage-gated calcium channels, reducing excitatory neurotransmitter release

FDA-Approved Use

Partial seizures, postherpetic neuralgia

Off-Label Use

Neuropathic pain, fibromyalgia, anxiety disorders, bipolar disorder, alcohol withdrawal and dependence, restless legs syndrome (RLS), postoperative pain adjunct, Lewy body dementia (LBD), agitation and aggression in dementia

Formulation

Oral capsules, tablets, extended-release tablets, oral solution

Titration

300 mg p.o. nightly, titrated gradually as clinically indicated

Dose Range

900–3600 mg/day in divided doses

Kinetics

Not metabolized; renal excretion; half-life 5–7 hours; dose adjustments required in renal impairment

Common AEs

Dizziness, drowsiness, peripheral edema, fatigue

Serious/Rare AEs

Respiratory depression (especially with CNS depressants), rare hypersensitivity reactions

Monitoring

Monitor for signs of misuse or abuse; assess respiratory function in at-risk populations

Black Box Warning

None

Considerations

Use cautiously in elderly patients and those with respiratory compromise due to increased risk of sedation and respiratory depression. Limited evidence supports use in neuropathic pain related to multiple sclerosis (MS). Potential benefits in managing behavioral symptoms such as agitation and aggression in dementia require individualized assessment.