felbamate
Brand names: Felbatol
Felbamate is a medicine used to treat seizures. It is usually only prescribed when other treatments haven't worked well enough due to the risk of serious side effects.
Drug Pricing (NADAC)
Brand Price
$14.03/unit
Generic Price
$0.82/unit
Generic Savings
94%
Generic Available
Yes (7 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Felbamate treats partial seizures in adults, both with and without generalization.
Common side effects
Loss of appetite, Vomiting, Trouble sleeping
Key warnings
Felbamate can cause a severe type of anemia called aplastic anemia.
How It Works
Felbamate is an anticonvulsant, meaning it helps to control seizures. The exact way it works in the brain is not fully understood. It is thought to affect certain chemicals in the brain that are involved in seizures.
How to Take It
Take felbamate exactly as your doctor tells you. It is usually taken 3 or 4 times a day. If you have kidney problems, your doctor may prescribe a lower dose. Your doctor may also adjust the doses of other seizure medicines you are taking to avoid side effects.
Pregnancy & Breastfeeding
It is not known if felbamate can harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if felbamate passes into breast milk, so talk to your doctor if you are breastfeeding.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is close to your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store felbamate oral suspension at room temperature, between 68° to 77°F (20° to 25°C), in a tightly closed container.
Side Effects (from patient reports)
Based on 1,332 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 1,714 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
1,714
Death-Related Reports
86
Hospitalization Reports
529
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | SEIZURE | 345 |
| 2 | DRUG INEFFECTIVE | 251 |
| 3 | CONVULSION | 124 |
| 4 | OFF LABEL USE | 115 |
| 5 | SOMNOLENCE | 108 |
| 6 | CONDITION AGGRAVATED | 92 |
| 7 | FATIGUE | 85 |
| 8 | DRUG INTERACTION | 71 |
| 9 | TOXICITY TO VARIOUS AGENTS | 71 |
| 10 | VOMITING | 70 |
| 11 | FALL | 60 |
| 12 | GENERALISED TONIC-CLONIC SEIZURE | 60 |
| 13 | DIARRHOEA | 59 |
| 14 | WEIGHT DECREASED | 52 |
| 15 | PNEUMONIA | 50 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Felbamate can cause a severe type of anemia called aplastic anemia. This condition is very serious and can be deadly. Because of this risk, felbamate should only be used if your epilepsy is very severe and other treatments have not worked. Felbamate can also cause liver failure. Talk to your doctor about these risks before starting felbamate.
Known Drug Interactions
The selective serotonin reuptake inhibitors sertraline (weak CYP3A4 inducer) and fluoxetine (CYP2D6 inhibitor), and the anti-epileptic drug felbamate (CYP2C19 inhibitor and CYP3A4 inducer) do not affect the pharmacokinetics of clonazepam.
Mechanism: Felbamate does not change the levels of clonazepam in the body or how it is processed.
What to do: These medications can be used together because they do not have a significant interaction.
Effects of Erythromycin on Felbamate The coadministration of erythromycin (1000 mg/day) for 10 days did not alter the pharmacokinetic parameters of C max , C min , AUC, Cl/kg or T max at felbamate daily doses of 3000 or 3600 mg/day in 10 otherwise healthy subjects with epilepsy.
Mechanism: Erythromycin does not change the amount of felbamate that stays in your system.
What to do: You can take these two drugs together without needing to change your felbamate dose.
CBZ epoxide ↓ ↑ ↓ Phenobarbital ↑ ↓ Specific Effects of Felbamate on Other Antiepileptic Drugs Phenytoin Felbamate causes an increase in steady-state phenytoin plasma concentrations. Phenobarbital Coadministration of felbamate with phenobarbital causes an increase in phenobarbital plasma concentrations. In 12 otherwise healthy male volunteers ingesting phenobarbital, the steady-state trough (C min ) phenobarbital concentration was 14.2 micrograms/mL.
Mechanism: Felbamate causes the level of phenobarbital in your blood to rise.
What to do: Your doctor may need to lower your phenobarbital dose and monitor your blood levels closely.
Drugs that have been shown, or that would be expected, to decrease plasma carbamazepine levels include cisplatin, doxorubicin HCl, felbamate, fosphenytoin, rifampin, phenobarbital, phenytoin, primidone, methsuximide, theophylline, aminophylline.
Mechanism: Felbamate causes your body to process carbamazepine more quickly, which can lead to lower levels of the drug in your system.
What to do: Your doctor may need to monitor your blood levels or adjust your dose of carbamazepine.
Some drugs or herbal products that may decrease the effectiveness of hormonal contraceptives include phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampin, topiramate and products containing St.
Mechanism: Felbamate can cause your body to process birth control hormones faster, which makes the pill less effective at preventing pregnancy.
What to do: You should use an extra form of birth control, such as condoms, while taking these medicines together.
Common Questions
Can I start felbamate as the first medicine for my seizures?
What should I do if I experience side effects?
Will I need blood tests while taking felbamate?
Can I take felbamate with other seizure medicines?
How quickly will felbamate start working?
Can I stop taking felbamate suddenly?
Does felbamate interact with other medications?
What happens if I take too much felbamate?
Can I drink alcohol while taking felbamate?
How often will I see my doctor while taking felbamate?
What are the common side effects of felbamate?
Does felbamate interact with other medications?
What drug class is felbamate?
Is there a generic version of felbamate?
Is felbamate safe during pregnancy?
Related Medications in Anticonvulsant
Other drugs grouped near felbamate — same-class peers and common alternatives.
brivaracetam
Briviact
Brivaracetam is a medicine used to treat partial-onset seizures.
Compare with felbamate →
cannabidiol
Epidiolex
Epidiolex is a medicine that contains cannabidiol.
Compare with felbamate →
carbamazepine
Tegretol
Carbamazepine is a medicine used to control seizures and treat nerve pain.
Compare with felbamate →
cenobamate
Xcopri
Xcopri is a medicine used to treat partial-onset seizures in adults.
Compare with felbamate →
clobazam
Onfi, Sympazan
Clobazam oral suspension is a medicine used with other medicines to treat seizures caused by Lennox-Gastaut syndrome.
Compare with felbamate →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
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Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for felbamate
The FDA label for felbamate (sold under brand names such as Felbatol) classifies it as a prescription-only medication in the Anticonvulsant class. Felbamate treats partial seizures in adults, both with and without generalization. Official labeling lists 7 commonly reported side effects, including Loss of appetite, Vomiting, Trouble sleeping.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 1,332 voluntary reports. The database also lists 16 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.82 versus $14.03 for the brand — a 94% generic savings.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: June 21, 2017
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages