Overview
DESCRIPTION Felbamate oral suspension, USP is an antiepileptic available as 600 mg/5 mL suspension for oral administration. Its chemical name is 2-phenyl-1,3-propanediol dicarbamate. Felbamate is a white to off-white crystalline powder with a characteristic odor. It is very slightly soluble in water, slightly soluble in ethanol, sparingly soluble in methanol, and freely soluble in dimethyl...
Mechanism of Action
CLINICAL PHARMACOLOGY Mechanism of Action The mechanism by which felbamate exerts its anticonvulsant activity is unknown, but in animal test systems designed to detect anticonvulsant activity, felbamate has properties in common with other marketed anticonvulsants. Felbamate is effective in mice and rats in the maximal electroshock test, the subcutaneous pentylenetetrazol seizure test, and the subcutaneous picrotoxin seizure test. Felbamate also exhibits anticonvulsant activity against seizures induced by intracerebroventricular administration of glutamate in rats and N-methyl-D,L-aspartic acid in mice.
Indications
- INDICATIONS AND USAGE Felbamate oral suspension, USP is not indicated as a first line antiepileptic treatment (see Warnings ). Felbamate oral suspension is recommended for use only in those patients who respond inadequately to alternative treatments and whose epilepsy is so severe that a substantial risk of aplastic anemia and/or liver failure is deemed acceptable in light of the benefits conferred by its use. If these criteria are met and the patient has been fully advised of the risk, and has provided written acknowledgement, felbamate can be considered for either monotherapy or adjunctive...
Common Doses
- 3600 mg
- 1200 mg
- 2400 mg
- 15 mg
Dosage
DOSAGE AND ADMINISTRATION Felbamate has been studied as monotherapy and adjunctive therapy in adults and as adjunctive therapy in children with seizures associated with Lennox-Gastaut syndrome. As felbamate is added to or substituted for existing AEDs, it is strongly recommended to reduce the dosage of those AEDs in the range of 20 to 33% to minimize side effects (see Drug Interactions subsection). Dosage Adjustment in the Renally Impaired Felbamate should be used with caution in patients with renal dysfunction.
Black Box Warning
WARNING 1. APLASTIC ANEMIA THE USE OF FELBAMATE ORAL SUSPENSION, USP IS ASSOCIATED WITH A MARKED INCREASE IN THE INCIDENCE OF APLASTIC ANEMIA. ACCORDINGLY, FELBAMATE ORAL SUSPENSION SHOULD ONLY BE USED IN PATIENTS WHOSE EPILEPSY IS SO SEVERE THAT THE RISK OF APLASTIC ANEMIA IS DEEMED ACCEPTABLE IN LIGHT OF THE BENEFITS CONFERRED BY ITS USE (SEE INDICATIONS ). ORDINARILY, A PATIENT SHOULD NOT BE PLACED ON AND/OR CONTINUED ON FELBAMATE ORAL SUSPENSION WITHOUT CONSIDERATION OF APPROPRIATE EXPERT HEMATOLOGIC CONSULTATION.
Contraindications
- CONTRAINDICATIONS Felbamate oral suspension, USP is contraindicated in patients with known hypersensitivity to felbamate oral suspension, its ingredients, or known sensitivity to other carbamates. It should not be used in patients with a history of any blood dyscrasia or hepatic dysfunction.
Side Effects
- ADVERSE REACTIONS To report SUSPECTED ADVERSE REACTIONS, contact Taro at 1-866-923-4914 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. The most common adverse reactions seen in association with felbamate in adults during monotherapy are anorexia, vomiting, insomnia, nausea, and headache. The most common adverse reactions seen in association with felbamate in adults during adjunctive therapy are anorexia, vomiting, insomnia, nausea, dizziness, somnolence, and headache.
Interactions
- Drug Interactions The drug interaction data described in this section were obtained from controlled clinical trials and studies involving otherwise healthy adults with epilepsy. Use in Conjunction with Other Antiepileptic Drugs (see DOSAGE AND ADMINISTRATION ) The addition of felbamate to antiepileptic drugs (AEDs) affects the steady-state plasma concentrations of AEDs. The net effect of these interactions is summarized in Table 2: Table 2 Steady-State Plasma Concentrations of Felbamate When Coadministered With Other AEDs AED Coadministered AED Concentration Felbamate Concentration Phenytoin...