Last reviewed 2026-04-20 · How we verify

Neurontin (gabapentin)

Binds the alpha-2-delta subunit of voltage-gated calcium channels, modulating neurotransmitter release to treat neuropathic pain and seizures.

Gabapentin (Neurontin) is a marketed generic drug originally developed by Parke-Davis/Pfizer, primarily indicated for postherpetic neuralgia. Its key strength lies in its mechanism of action, binding the alpha-2-delta subunit of voltage-gated calcium channels to modulate neurotransmitter release, effectively treating neuropathic pain and seizures. The primary risk is the key composition patent expiry in 2028, which may increase competition from other generics.

At a glance

Mechanism of action

Gabapentin was originally designed as a GABA analog but does not actually bind GABA receptors. Instead, it binds the alpha-2-delta subunit of voltage-gated calcium channels, reducing excitatory neurotransmitter release. While approved for epilepsy, it is far more commonly prescribed for neuropathic pain, making it one of the top 10 most prescribed medications in the US.

Approved indications

• Postherpetic Neuralgia
• Partial Onset Seizures

Common side effects

• Somnolence
• Dizziness
• Ataxia
• Fatigue
• Nystagmus
• Tremor
• Peripheral edema
• Increased weight
• Dysarthria
• Dyspepsia
• Dry mouth or throat
• Constipation

Drug interactions

• Opioids (e.g., morphine, hydrocodone, oxycodone, buprenorphine)
• Hydrocodone
• Morphine
• Other Antiepileptic Drugs
• Maalox ® (aluminum hydroxide, magnesium hydroxide)

Key clinical trials

• Phase III Double-Blind, Placebo-Controlled Study of Gabapentin for the Prevention of Delayed CINV (Chemotherapy Induced Nausea and Vomiting) in Patients Receiving Highly Emetogenic Chemotherapy (Phase 3)
• Comparative Clinical Study Among Ondansetron and Gabapentin in Preventing Postoperative Nausea and Vomiting After Laparoscopic Sleeve Gastrectomy (Phase 3)
• Comparison of Gabapentin and Metoclopramide for Treating Hyperemesis Gravidarum (Phase 2)
• NCT01421264 (Phase 1)
• Bioequivalence Study Between Two Medications for Administration of Oral Gabapentin in 300 mg Capsules in Healthy Volunteers (Phase 1)
• Ultrasound-Guided Erectro Spinae Plane Block Versus Stellate Ganglion Block for Patients With Upper Limb Acute Herpes Zoster Pain: Randomized Controlled Study (NA)
• A Randomized, Double Blind, Active and Placebo Controlled, 5 Way Crossover Study to Determine the Abuse Potential of Orally Administered Gabapentin Enacarbil Immediate Release Capsules in Healthy, Non (Phase 4)
• Phase I/II Study of Intravenous Infusion of Tetra-o-Methyl Nordihydroguaiaretic Acid (EM-1421) in Subjects With Recurrent High Grade Glioma (Phase 1)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.