Vetdrugs 2.0Felbamate is an anticonvulsant used extra-label for selected dogs with epilepsy that remains poorly controlled on other drugs. It is generally employed as adjunctive therapy rather than as a routine first choice. Veterinary experience is comparatively limited, and its therapeutic role depends on seizure pattern, prior response and the overall anticonvulsant regimen.
Group
Anticonvulsant
Mechanism of Action
Felbamate reduces excitatory neurotransmission in part through antagonism of NMDA-receptor-mediated signaling. Additional proposed effects include modulation of GABA-A-mediated inhibition and voltage-dependent ion-channel activity. Together, these actions can reduce neuronal excitability and seizure propagation. The relative contribution of each mechanism to clinical seizure control in dogs has not been fully defined.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Refractory epilepsy — Initial | 15–20 mg/kg | PO | Every 8 h | |
| Refractory epilepsy — Maintenance | 70 mg/kg | PO | Every 8 h | Upper reported regimen, not a starting amount; titrate gradually and monitor toxicity. |
| Small-dog epilepsy regimen — Initial | 200 mg/animal | PO | Every 8 h | Maximum 600 mg/dose; Source does not define the small-dog weight boundary; individualized fixed regimen. Maximum 600 mg/dog per administration. |
| Large-dog epilepsy regimen — Initial | 400 mg/animal | PO | Every 8 h | Maximum 1200 mg/dose; Source does not define the large-dog weight boundary; increase in 200 mg steps to effect, maximum 1200 mg/dog per administration. |
| Seizure control | 15–65 mg/kg | PO | Every 8 h | Alternative adjunct or third-line regimen; monitor CBC and liver function. |
| Refractory seizures adjunct | 5–20 mg/kg | PO | Every 8 h | When phenobarbital and bromide are ineffective or poorly tolerated; assess their serum concentrations and adjust excessive doses. |
| Seizure-dose escalation | Reference only | PO | Start 15 mg/kg every 8 hours; increase in 15 mg/kg steps no more often than every two weeks according to response. Some reported dogs required 70 mg/kg every 8 hours. Monitor CBC and hepatic function throughout escalation. |
Indications
- Adjunctive treatment of refractory epilepsy, including selected focal or generalized seizure disorders, in dogs whose seizures are inadequately controlled by other anticonvulsants; veterinary clinical evidence is limited.
Contraindications
- Use cautiously with hepatic disease or marrow abnormalities.
Interactions
- Can raise phenobarbital concentrations and increase hepatic injury risk.
Adverse effects
- Hepatotoxicity
- Blood dyscrasias
- Tremors, agitation and salivation
- Keratoconjunctivitis sicca
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Felbamate 400 mg | Tablet | 400 mg / tablet | PO |
| Felbamate 600 mg | Tablet | 600 mg / tablet | PO |
| Felbamate oral suspension 120 mg/mL | Oral Liquid | 120 mg / mL | PO |
Monitoring and Administration
Monitor CBC, hepatic biochemistry and seizure control. Plasma therapeutic targets are not established for dogs.
Increase gradually according to response; source maximum is approximately 70 mg/kg every 8 hours.