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Felbamate Side Effects

The most commonly reported side effects of felbamate include seizure, off label use, and somnolence, based on 1,748 FDA adverse event reports from 2004 to 2025. 13.4% of reports found the drug to be ineffective.

Felbamate side effects

Percentages show how often each reaction appears relative to total reports for felbamate.

1
Seizure20.0%350
2
Drug Ineffective13.4%235
3
Off Label Use6.6%115
4
Somnolence5.8%101
5
Fatigue4.6%80
6
Convulsion4.4%77
7
Condition Aggravated4.2%74
8
Toxicity To Various Agents4.1%72
9
Generalised Tonic-clonic Seizure3.5%61
10
Vomiting3.4%60
11
Drug Interaction3.4%60
12
Convulsion3.0%53
13
Diarrhoea3.0%52
14
Fall3.0%52
15
Pneumonia2.8%49

These are voluntary reports and do not establish that felbamate caused these reactions.

Report severity

71.3%Serious1,246 reports
30.7%Hospitalizations536 reports
5.0%Fatal88 reports

Seriousness is determined by the reporter, not by OpenClaim.

Felbamate drug interactions

Other drugs that appear in adverse event reports alongside felbamate. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Levetiracetam18.1%317
2
Cannabidiol17.3%302
3
Clobazam16.0%280
4
Lacosamide14.9%260
5
Vigabatrin13.9%243
6
Phenobarbital-sodium10.9%190
7
Topiramate10.7%187
8
Lamotrigine10.1%177
9
Phenytoin8.4%147
10
Valproic-acid8.4%146
11
Zonisamide7.0%122
12
Clonazepam5.9%104
13
Carbamazepine5.7%100
14
Oxcarbazepine5.7%99
15
Fenfluramine4.4%77

Taken alongside

1
Clobazam22.8%398
2
Levetiracetam17.5%306
3
Clonazepam15.9%278
4
Lamotrigine12.5%219
5
Divalproex-sodium11.5%201
6
Diazepam10.6%185
7
Topiramate10.5%183
8
Lorazepam10.4%181
9
Zonisamide9.4%165
10
Lacosamide9.0%158
11
Rufinamide7.3%128
12
Phenobarbital-sodium6.4%111
13
Ergocalciferol6.2%108
14
Phenytoin6.0%105
15
Midazolam5.8%102

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports felbamate side effects

40.7% of felbamate adverse event reports involve female patients and 37.6% involve male patients. The largest age group is adult at 54%. These figures reflect who reports side effects, not underlying risk.

Sex

Female40.7%
Male37.6%
Unknown21.6%

Age group

< 23.3%
2–1126.2%
12–1713.9%
18–6453.8%
65+2.9%

What is felbamate used for

Conditions and purposes for which patients were taking felbamate when the adverse event was reported.

Atonic SeizuresAutismAcquired Epileptic AphasiaAtonic SeizuresCarbon Monoxide PoisoningCerebral PalsyComplex Partial SeizuresConvulsionConvulsion ProphylaxisCerebrohepatorenal SyndromeChange In Seizure PresentationDrug Use For Unknown IndicationEpilepsyEyelid MyoclonusEncephalitis

Showing 15 of 64 indications

Felbamate brand names and reporting trend

Felbamate is sold under the brand name Felbatol.

Brand names

Felbatol1,329

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking felbamate with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.