Felbamate

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Cat Number

API0231556

CAS Number

25451-15-4

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Product Detail Description Scientific Support Customer Q&A

CAS Number

25451-15-4

EINECS

247-001-4

Storage

Store at room temperature

Synonyms

Felbatol; 2-Phenyl-1,3-propanediol dicarbamate; Taloxa; Felbamato; Felbamatum; W-554; 1,3-Propanediol, 2-phenyl-, dicarbamate; ADD-03055

Molecular Formula

C11H14N2O4

Molecular Weight

238.24

Smiles

C1=CC=C(C=C1)C(COC(=O)N)COC(=O)N

Appearance

White to off-white powder

Melting Point

148-150℃

Boiling Point

511.9±50.0℃

Relative Density

1.275

General Description

Felbamate is a broad-spectrum anticonvulsant agent approved for the treatment of severe epilepsy, specifically Lennox-Gastaut syndrome and partial-onset seizures. It is available in oral tablets and suspension and is structurally distinct from other antiseizure medications, being a dicarbamate derivative.

Mechanism of Action

Felbamate exerts its anticonvulsant effects through multiple mechanisms, including modulation of the N-methyl-D-aspartate (NMDA) receptor complex at the glycine recognition site. It also potentiates gamma-aminobutyric acid (GABA)-mediated responses and blocks voltage-gated sodium channels. This multi-modal action reduces neuronal hyperexcitability and limits seizure propagation. The drug does not have significant affinity for benzodiazepine or barbiturate binding sites.

Application

It is indicated as monotherapy or adjunctive therapy for partial-onset seizures in adults and for the treatment of Lennox-Gastaut syndrome in children, a severe epileptic encephalopathy. Due to the risk of aplastic anemia and acute hepatic failure, felbamate is reserved for patients with refractory epilepsy who have failed adequate trials of other anticonvulsants and whose benefit outweighs the risk. Regular hematologic and hepatic monitoring is mandatory.

This Cochrane review update identified four small, methodologically heterogeneous randomized trials (236 participants) comparing felbamate to placebo as add‑on treatment for drug‑resistant focal seizures. Meta‑analysis was not possible due to differences in outcome measures and study design. One study reported a 35.8% seizure reduction with felbamate versus placebo, another a modest 4.2% reduction, and a third found no significant difference. Withdrawal rates were low (<10%), suggesting reasonable tolerability, but adverse effects (headache, dizziness, nausea) occurred more frequently with felbamate (23‑40% vs. 3‑15%). The authors judge the evidence as very low certainty and conclude that no reliable evidence supports felbamate use in this setting; a large, long‑term randomized trial is needed.

Fig. 1 Flow chart of study selection. (Shi LL, et al., 2019)

References

Shi LL, et al. Felbamate add-on therapy for drug-resistant focal epilepsy. Cochrane Database Syst Rev. 2019; 8(8):CD008295.

Does Felbamate require protection from moisture during long-term storage?

Yes, it is slightly hygroscopic. Store in tightly sealed, moisture-proof containers with desiccant to prevent caking and potential hydrolysis of the carbamate groups.

What is the recommended storage temperature for Felbamate?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can accelerate degradation and cause discoloration.

Is Felbamate sensitive to light, and how does this affect stability?

It is moderately photosensitive. Prolonged light exposure may cause yellowing. Store in light-resistant containers, preferably original opaque packaging.

How is the impurity 2-phenyl-1,3-propanediol dicarbamate monitored?

This process-related impurity is quantified using a stability-indicating HPLC method, ensuring it remains within pharmacopoeial limits throughout shelf life.