What the label lists and what reports show
Gabapentin side effects
Gabapentin's FDA label: “Most common adverse reactions (incidence ≥8% and at least twice that for placebo) were: • Postherpetic neuralgia: Dizziness, somnolence, and peripheral edema ( 6.1 ) • Epilepsy in patients >12 years of age: Somnolence, dizziness, ataxia, fatigue, and …” FAERS holds 362,654 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (25,140 reports).
- Generic listed
Check it at the source: the gabapentin FDA label on DailyMed (effective May 12, 2026, Viatris Specialty LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of NEURONTIN?NEURONTIN may cause serious side effects, including: • See “What is the most important information I should know about NEURONTIN?” • problems driving while using NEURONTIN. See “What should I avoid while taking NEURONTIN?” • sleepiness and dizziness, which could increase your chance of having an accidental injury, including falls. The most common side effects of NEURONTIN include: • lack of coordination • viral infection • difficulty with speaking • tremor • swelling, usually of legs and feet • feeling tired • fever • feeling drowsy • nausea and vomiting • jerky movements • difficulty with coordination • double vision • unusual eye movement Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of NEURONTIN. For more information, ask your healthcare provider or pharmacist. […]
Source: FDA drug label, Viatris Specialty LLC, effective May 12, 2026 (SPL set 97935fd9-1d4a-43b6-a5d9-de994591187b), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence ≥8% and at least twice that for placebo) were: • Postherpetic neuralgia: Dizziness, somnolence, and peripheral edema ( 6.1 ) • Epilepsy in patients >12 years of age: Somnolence, dizziness, ataxia, fatigue, and nystagmus ( 6.1 ) • Epilepsy in patients 3 to 12 years of age: Viral infection, fever, nausea and/or vomiting, somnolence, and hostility
TABLE 4. Adverse Reactions in Pooled Placebo-Controlled Add-On Trials in Epilepsy Patients >12 Years of Age
| Reaction | NEURONTIN Plus background antiepileptic drug therapy N=543 % | Placebo N=378 % |
|---|---|---|
| Fatigue | 11 | 5 |
| Increased weight | 3 | 2 |
| Back pain | 2 | 1 |
| Peripheral edema | 2 | 1 |
| Vasodilatation | 1 | 0 |
| Dyspepsia | 2 | 1 |
| Dry mouth or throat | 2 | 1 |
| Constipation | 2 | 1 |
| Dental abnormalities | 2 | 0 |
| Somnolence | 19 | 9 |
| Dizziness | 17 | 7 |
| Ataxia | 13 | 6 |
| Nystagmus | 8 | 4 |
| Tremor | 7 | 3 |
| Dysarthria | 2 | 1 |
| Amnesia | 2 | 0 |
| Depression | 2 | 1 |
| Abnormal thinking | 2 | 1 |
| Abnormal coordination | 1 | 0 |
| Pharyngitis | 3 | 2 |
| Coughing | 2 | 1 |
| Abrasion | 1 | 0 |
| Impotence | 2 | 1 |
| Diplopia | 6 | 2 |
| Amblyopia Amblyopia was often described as blurred vision. | 4 | 1 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following serious adverse reactions are discussed in greater detail in other sections: • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity [see Warnings and Precautions (5.1) ] • Anaphylaxis and Angioedema [see Warnings and Precautions (5.2) ] • Somnolence/Sedation and Dizziness [see Warnings and Precautions (5.4) ] • Suicidal Behavior and Ideation [see Warnings and Precautions (5.5) ] • Increased Risk of Seizures and Other Adverse Reactions with Abrupt or Rapid Discontinuation [see Warnings and Precautions (5.6) ] • Status Epilepticus [see Warnings and Precautions (5.7) ] • Respiratory Depression [see Warnings and Precautions (5.8) ] • Neuropsychiatric Adverse Reactions (Pediatric Patients 3 to 12 Years of Age) [see Warnings and Precautions (5.9) ] Most common adverse reactions (incidence ≥8% and at least twice that for placebo) were: • Postherpetic neuralgia: Dizziness, somnolence, and peripheral edema ( 6.1 ) • Epilepsy in patients >12 years of age: Somnolence, dizziness, ataxia, fatigue, and nystagmus ( 6.1 ) • Epilepsy in patients 3 to 12 years of age: Viral infection, fever, nausea and/or vomiting, somnolence, and hostility ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Viatris at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. …
Source: FDA drug label, Viatris Specialty LLC, effective May 12, 2026 (SPL set 97935fd9-1d4a-43b6-a5d9-de994591187b), via openFDA; the full label on DailyMed
What do FAERS reports show?
362,654 reports list gabapentin among the medicines taken, each a report of something that happened, not proof the medicine caused it; 34,219 are coded as a death and 106,727 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 13 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Gabapentin: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions