Gabapentin: uses, side effects and safety
Gabapentin (Neurontin) is a anticonvulsant; analgesic for neuropathic pain. It has no US federal controlled-substance schedule. It is prescription only (rx) and remains on the US market.
What is Gabapentin?
Gabapentin is the generic name for Neurontin, and belongs to the Anticonvulsant; analgesic for neuropathic pain class.
| Generic name | gabapentin |
|---|---|
| Brand name(s) | Neurontin |
| Drug class | Anticonvulsant; analgesic for neuropathic pain |
| US legal status | No US federal schedule · Prescription only (Rx) |
| Route | Oral |
| Prescription required | Yes |
| Elimination half-life | 5-7 hours (unaltered by dose or multiple dosing); approximately 132 hours in anuric patients off dialysis, reduced to 3.8 hours during hemodialysis |
| Metabolism | Not appreciably metabolized in humans. All pharmacological actions are due to the parent compound; eliminated unchanged by the kidneys, with elimination rate constant, plasma clearance and renal clearance directly proportional to creatinine clearance. |
What is Gabapentin used for?
Gabapentin is approved by the FDA for the following uses. Approval is granted per indication, and a specific product may not be approved for all of them.
- Management of postherpetic neuralgia in adults
- Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy
How does Gabapentin work?
The precise mechanisms by which gabapentin produces its analgesic and antiepileptic actions are unknown. Structurally related to GABA but has no effect on GABA binding, uptake, or degradation. In vitro it binds with high affinity to the alpha-2-delta subunit of voltage-activated calcium channels; the relationship of this binding to therapeutic effects is unknown..
It is metabolised primarily by Not appreciably metabolized in humans. All pharmacological actions are due to the parent compound; eliminated unchanged by the kidneys, with elimination rate constant, plasma clearance and renal clearance directly proportional to creatinine clearance..
The elimination half-life is roughly 5-7 hours (unaltered by dose or multiple dosing); approximately 132 hours in anuric patients off dialysis, reduced to 3.8 hours during hemodialysis. Longer half-lives mean the drug and its active metabolites persist in the body for longer after the last dose.
Common side effects of Gabapentin
These are the side effects people report most often. Many diminish after the body adjusts, usually within one to two weeks.
- Dizziness
- Somnolence
- Ataxia
- Peripheral edema
- Fatigue
- Nystagmus
- Nausea and vomiting (pediatric)
What does Gabapentin interact with?
Interactions matter because two safe medicines can become dangerous together. The entries below are the ones most likely to cause harm.
- Opioids (morphine, hydrocodone, oxycodone, buprenorphine): respiratory depression and sedation, sometimes resulting in death; gabapentin exposure increases with morphine
- Hydrocodone: co-administration decreases hydrocodone exposure; consider when gabapentin is started or discontinued
- Other antiepileptic drugs: gabapentin is not appreciably metabolized and does not induce or inhibit their metabolism
- Antacids such as Maalox or Mylanta: take at least 2 hours before gabapentin tablets, capsules or solution
Use our drug interaction checker before combining any two prescriptions.
Serious side effects and warning signs
Seek emergency care for any of these
- Respiratory depression and sedation, sometimes resulting in death, when co-administered with opioids
- Somnolence and sedation leading to impaired driving and operation of heavy machinery
- Suicidal behavior and ideation (CNS depressants, including anticonvulsants, increase risk)
- Newly identified tumors in adjunctive epilepsy therapy (breast, brain, lung, adrenal, non-Hodgkin lymphoma)
Suspected overdose or a bad reaction should be reported to Poison Control on 1-800-222-1222. That is staffed around the clock and is free.
Legal status of Gabapentin
Gabapentin has no US federal controlled-substance schedule. An unscheduled medicine is not an over-the-counter medicine: it remains prescription-only, and individual states may regulate it independently. State rules are covered in our state-by-state section.
Important note
schedule is null because gabapentin does not appear anywhere in 21 CFR 1308.11-1308.15 - this is a verified absence, not a missing lookup, and it is not the same as Schedule V (pregabalin is Schedule V at 1308.15(f)(7)). onsetHours and peakHours are null: the label gives peak plasma concentrations of 2-3 hours only for pediatric subjects aged 1 month to 12 years at approximately 10 mg/kg, and gives no adult Tmax or onset figure; MedlinePlus gives none either. Gabapentin extended-release (Horizant) for restless legs syndrome is a separate product and is not covered by this entry.
Can you get Gabapentin without a prescription?
Short answer: no. Gabapentin is a prescription medication. Sites advertising it without one are either operating illegally or selling something other than what they claim. We explain the legal routes, the counterfeit problem and how to check a source in detail.
Read the full answer: Gabapentin without a prescription →
Frequently asked questions
What is Gabapentin used for?
Management of postherpetic neuralgia in adults Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy
Is Gabapentin a controlled substance?
Gabapentin has no US federal controlled-substance schedule. That is not the same as being available over the counter: it is still a prescription-only medicine, and a number of individual states regulate it separately.
What are the common side effects of Gabapentin?
The most frequently reported side effects are dizziness, somnolence, ataxia, peripheral edema, fatigue, nystagmus. Many lessen over the first week or two of treatment.
What should not be combined with Gabapentin?
The most clinically important interactions are with opioids (morphine, hydrocodone, oxycodone, buprenorphine): respiratory depression and sedation, sometimes resulting in death; gabapentin exposure increases with morphine, hydrocodone: co-administration decreases hydrocodone exposure; consider when gabapentin is started or discontinued, other antiepileptic drugs: gabapentin is not appreciably metabolized and does not induce or inhibit their metabolism, antacids such as maalox or mylanta: take at least 2 hours before gabapentin tablets, capsules or solution. Always give a pharmacist or prescriber a complete list of everything you take, including over-the-counter drugs and supplements.
Sources & references
Important
This site provides educational information only and does not sell, prescribe or dispense medications. Always consult a licensed healthcare provider. This page is not medical advice.