Gabapentin
Pronunciation: GA-ba-PEN-tin.
- Generic name
- gabapentin
- Drug class
- Anticonvulsant (antiepileptic drug), also used as an analgesic for neuropathic pain
- Form
- Capsule or tablet (100 mg, 300 mg, 400 mg, 600 mg, 800 mg)
- Route
- Oral
- Legal status
- Prescription-only
Availability and supply rules vary by country
Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand
Australia: Neurontin; generic gabapentin (e.g. Gapentin) (5) · Full directory
What gabapentin is and how it works
Gabapentin is a prescription-only anticonvulsant medicine also used to relieve certain types of nerve pain. It is taken by mouth, usually several times a day, with the dose built up gradually. (1) (2)
Take gabapentin exactly as your prescriber directs. Your dose is started low and increased gradually over days to weeks to find the amount that controls your seizures or pain with the fewest side effects -- it is not a fixed dose for everyone, and it should only ever be changed, reduced, or stopped under your prescriber's direction.
Mechanism of action: how gabapentin works
Gabapentin's precise mechanism of action is not fully established. It binds with high affinity to the alpha-2-delta subunit of voltage-gated calcium channels in the central nervous system, which is thought to reduce the release of excitatory neurotransmitters, contributing to both its antiseizure and analgesic effects; despite structural similarity to GABA, it does not act on GABA receptors, uptake, or degradation. (1) (2)
What gabapentin is used for
Epilepsy (partial-onset seizures)
Used as an add-on (adjunctive) treatment alongside other antiepileptic medicines for partial-onset seizures in adults and children, and as a stand-alone treatment in some countries for adults and adolescents. (1) (2)
Postherpetic neuralgia and other neuropathic pain
Used to manage nerve pain that can follow a shingles infection (postherpetic neuralgia), and other forms of peripheral neuropathic pain in adults. (1) (2)
Before taking gabapentin
Do not take / not appropriate for
- Do not take gabapentin if you have had a serious allergic reaction to gabapentin or any ingredient in the product. (all countries) (1) (2)
Tell your clinician about
- Any history of depression, mood changes, or suicidal thoughts.
- Any breathing or lung problems (such as COPD), or any condition that affects your breathing.
- Any kidney problems -- your dose usually needs to be adjusted based on kidney function.
- Any history of drug or alcohol misuse.
- All other medicines you take, especially opioid painkillers, sleeping tablets, or other medicines that can make you drowsy, and any antacids.
- Pregnancy, plans for pregnancy, or breastfeeding.
- If you drive or operate machinery, until you know how gabapentin affects you.
How to take gabapentin
- Take gabapentin exactly as prescribed, usually in 2-3 divided doses through the day.
- Swallow capsules/tablets whole with water; take with food if it upsets your stomach.
- If you also take an aluminium- or magnesium-containing antacid, take gabapentin at least 2 hours afterward, since antacids can reduce how much gabapentin your body absorbs.
- Any change to your dose, including stopping treatment or switching to another medicine, should only be done gradually and under your prescriber's direction -- typically over a minimum of one week, sometimes longer.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)
Missed dose
If you miss a dose, take it as soon as you remember unless it is almost time for your next dose -- in that case, skip the missed dose and continue your normal schedule. Do not take a double dose. Contact your prescriber or pharmacist if you are unsure, especially if you have missed more than one dose in a row.
Overdose
Seek urgent medical attention if you think you have taken too much gabapentin, or if you notice slowed or difficult breathing, extreme drowsiness, slurred speech, or loss of consciousness -- especially if gabapentin has been taken together with opioids, alcohol, or other sedating medicines. (1)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms.
Dizziness and drowsiness (somnolence).
What to notice: Dizziness and drowsiness (somnolence).
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)
Unsteadiness or problems with coordination (ataxia).
What to notice: Unsteadiness or problems with coordination (ataxia).
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)
Fatigue (tiredness).
What to notice: Fatigue (tiredness).
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)
Swelling of the hands, ankles, or feet (peripheral edema).
What to notice: Swelling of the hands, ankles, or feet (peripheral edema).
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)
Weight gain.
What to notice: Weight gain.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2)
In children: mood or behaviour changes, including irritability or hostility, and viral infection symptoms have been reported more often than with placebo.
What to notice: In children: mood or behaviour changes, including irritability or hostility, and viral infection symptoms have been reported more often than with placebo.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Serious warnings
Signs of respiratory depression (slowed or difficult breathing) — emergency
Symptoms: Unusually slow, shallow, or difficult breathing, extreme drowsiness, confusion, or difficulty waking up -- risk is higher when gabapentin is combined with opioids or other sedating medicines, or in people with existing breathing problems, respiratory disease, or in older adults.
Action: Seek emergency medical help immediately. This is a real, serious safety signal identified by regulators in the US, UK, EU, and Canada, particularly with opioid or CNS-depressant combinations or underlying respiratory impairment. (1) (2) (3) (4)
New or worsening depression, mood changes, or suicidal thoughts — high caution
Symptoms: Low mood, thoughts of self-harm or suicide, unusual changes in behaviour, anxiety, or agitation -- can appear as early as one week after starting treatment. This is a known class effect of antiepileptic medicines, including gabapentin.
Action: Contact your prescriber promptly if you or someone close to you notices these changes; seek emergency help if there is any immediate risk of self-harm. (1) (2)
Increased seizures if treatment is stopped abruptly — high caution
Symptoms: Return or worsening of seizures, including rare cases of prolonged seizure activity (status epilepticus); other people may notice anxiety, insomnia, nausea, or sweating after sudden discontinuation.
Action: Never change or stop gabapentin on your own -- any dose reduction, discontinuation, or switch to another medicine must be planned and supervised by your prescriber, typically tapered gradually over at least one week or longer. (1) (2)
Signs of a serious allergic or multi-organ hypersensitivity reaction — emergency
Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; widespread rash, fever, or swollen glands.
Action: Seek emergency medical help immediately. (1)
Signs of misuse or dependence — high caution
Symptoms: Taking more than the prescribed dose, seeking early refills, or strong cravings for the medicine -- gabapentin has a recognised, real potential for misuse and dependence, particularly in people with a history of substance use.
Action: Discuss any concerns about misuse or dependence openly with your prescriber, who can help manage this safely; never adjust your own dose. (1) (2)
Interactions
- Opioid painkillers (such as morphine or hydrocodone) and other CNS depressants (sleeping tablets, some anxiety medicines, alcohol) can increase drowsiness and the risk of serious breathing problems when combined with gabapentin -- this combination requires close medical supervision. (1) (2)
- Aluminium- or magnesium-containing antacids can reduce how much gabapentin your body absorbs -- take gabapentin at least 2 hours after taking these antacids. (1) (2)
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Observational human studies have not shown a clear increase in major birth defects or miscarriage, though animal studies showed some developmental effects at clinically relevant doses. Tell your prescriber if you are pregnant or planning pregnancy so the benefits and risks can be discussed for your situation; pregnancy registries exist in some countries to track outcomes. (1) (2) (3) (4) (5) (6)
Breastfeeding
Gabapentin passes into breast milk. Discuss the benefits of breastfeeding against your clinical need for the medicine with your prescriber. (1) (2) (3) (4) (5) (6)
Children
Approved as add-on epilepsy treatment from age 3 or 6 years depending on the country; mood and behaviour changes have been reported more often in children than adults, so these should be monitored. (1) (2) (3) (4) (5) (6)
Elderly
Older adults are at higher risk of drowsiness, unsteadiness, and respiratory depression, and often need a lower dose based on kidney function. (1) (2) (3) (4) (5) (6)
Hepatic_impairment
Not specifically addressed in the sources reviewed; gabapentin is eliminated mainly by the kidneys rather than the liver. (1) (2) (3) (4) (5) (6)
Renal_impairment
Dose must be reduced based on kidney function (creatinine clearance); people on haemodialysis need a supplemental dose after each dialysis session, as directed by their prescriber. (1) (2) (3) (4) (5) (6)
Source_ids
US-DAILYMED-GABAPENTIN-2026,UK-EMC-GABAPENTIN-2026 (1) (2) (3) (4) (5) (6)
Monitoring
Before starting
- Kidney function (creatinine clearance)
- Baseline mood/mental health history
- Respiratory status and any breathing conditions
- History of substance misuse
During treatment
- Watch for signs of drowsiness, breathing difficulty, or confusion, especially if also taking opioids or other sedating medicines.
- Monitor mood and behaviour, particularly in the first weeks of treatment.
- Track seizure frequency if being treated for epilepsy.
- Periodic kidney function checks, especially in older adults or those with existing kidney problems.
Storage
Store at controlled room temperature, about 25C (77F), with excursions permitted between 15-30C (59-86F) per the US label, or below 25C per the UK SmPC. Keep in the original packaging, out of reach of children.
Study the drug class: Antiepileptics
Professional information
Clinician-facing context only, sourced from the current US FDA prescribing information and UK SmPC; verify against the current full label before prescribing.
United States
Indication: Postherpetic neuralgia and adjunctive partial-onset seizure treatment
Dose summary: Postherpetic neuralgia: titrate from 300 mg on day 1 to a maximum of 1,800 mg/day in divided doses (doses above 1,800 mg/day showed no additional benefit in trials). Partial seizures (12+ years): start 300 mg three times daily; maintenance typically 300-600 mg three times daily. Paediatric epilepsy (3-11 years): weight-based dosing, titrated over about 3 days. Renal impairment requires dose reduction per creatinine clearance; haemodialysis patients require a supplemental post-dialysis dose.
Renal context: Dose reduction required based on creatinine clearance; specific dosing tables exist in the full label for CrCl categories down to <15 mL/min and for haemodialysis. (1)
United Kingdom
Indication: Epilepsy (adjunctive/monotherapy) and peripheral neuropathic pain
Dose summary: Initial titration from around 300 mg daily, increasing to maintenance doses generally in the range of 900-3,600 mg/day in three divided doses, individualised to response and tolerability; elderly and renally impaired patients require reduced doses per renal function tables.
Renal context: Dose adjustment required based on renal function; see full SmPC dosing tables. (2)
Hepatic guidance
Gabapentin is not significantly metabolised by the liver and is eliminated largely unchanged by the kidneys; it does not appreciably affect the metabolism of commonly co-administered antiepileptic drugs.
Overdose note
Overdose can cause double vision, slurred speech, drowsiness, lethargy, and diarrhoea; more seriously, respiratory depression and loss of consciousness can occur, particularly in combination with opioids or other CNS depressants -- manage with supportive care, and haemodialysis can be used to remove gabapentin in significant renal impairment. (1) (2)
Frequently asked questions
Is gabapentin available in the US, UK, Europe, Canada, Australia, and New Zealand?
Yes, it is approved and available in all of these regions, mostly as generic gabapentin, with the originator brand Neurontin also still licensed in several markets. (1) (2) (3) (4) (5) (6)
Can I stop taking gabapentin suddenly if I feel better?
No -- stopping gabapentin suddenly can increase the risk of seizures returning or worsening, even in people without epilepsy. Any change to your dose or stopping treatment should always be planned and supervised by your prescriber, typically with a gradual taper over at least a week or longer. (1) (2)
Is it dangerous to take gabapentin with opioid painkillers?
Combining gabapentin with opioids or other sedating medicines increases the risk of serious, potentially life-threatening slowed breathing (respiratory depression). This combination should only be used under close medical supervision. (1) (2) (3) (4)
What is the mechanism of action of gabapentin?
Gabapentin's precise mechanism of action is not fully established. It binds with high affinity to the alpha-2-delta subunit of voltage-gated calcium channels in the central nervous system, which is thought to reduce the release of excitatory neurotransmitters, contributing to both its antiseizure and analgesic effects; despite structural similarity to GABA, it does not act on GABA receptors, uptake, or degradation. (1) (2)
References
- GABAPENTIN tablet/capsule -- full prescribing information (revised 4/2026)U.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · accessed 2026-07-30 · source 1
- Gabapentin 100mg Capsules -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Milpharm Limited · United Kingdom · accessed 2026-07-30 · source 2
- Gabapentin: CMDh scientific conclusions and grounds for variation of the product information (PSUSA/00001499/202202); PRAC recommendations on signalsEuropean Medicines Agency (EMA) -- CMDh scientific conclusions and PRAC recommendations · European Union · accessed 2026-07-30 · source 3
- NEURONTIN (gabapentin) Product MonographHealth Canada product monograph · Canada · accessed 2026-07-30 · source 4
- NEURONTIN gabapentin capsules/tablets -- ARTG entries (e.g. ARTG 66008, 66005, 74067, 71793, 71791)Therapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-30 · source 5
- NEURONTIN (gabapentin) New Zealand Data Sheet; Medsafe Prescriber Update on gabapentin/pregabalin for neuropathic painMedsafe (New Zealand regulator) · New Zealand · accessed 2026-07-30 · source 6
Brand names by country
Single-ingredient gabapentin names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- Neurontin100 mg, 400 mg, 250 mg/5mL, 300 mg, 600 mg, 800 mg · viatris specialty llc
- Gralise600 mg, 750 mg, 450 mg, 300 mg, 900 mg · almatica pharma llc
- RELGAABI300 mg, 400 mg, 200 mg · method pharmaceuticals, llc
- GABARONE100 mg, 400 mg · ina pharmaceutics inc.
United Kingdom
- Gabapentin (generic); Neurontin (2)MHRA licensed emc smpc confirmed · 100 mg, 300 mg, 400 mg, 600 mg, 800 mg · Milpharm Limited (generic); Viatris (Neurontin)
Canada
- NEURONTIN
Australia
- Neurontin; generic gabapentin (e.g. Gapentin) (5)TGA ARTG registered confirmed · 100 mg, 300 mg, 400 mg, 600 mg, 800 mg · Viatris Pty Ltd
New Zealand
- Neurontin; generic gabapentin (e.g. APO-GABAPENTIN, Nupentin) (6)Medsafe approved confirmed · 100 mg, 300 mg, 400 mg, 600 mg, 800 mg · multiple
View brands in additional countries.
European Union
Gabapentin (nationally authorised, various brand names by member state) (3)