Felbatol® is not indicated as a first line antiepileptic treatment (see WARNINGS). Felbatol® 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, Felbatol® can be considered for either monotherapy or adjunctive therapy in the treatment of partial seizures, with and without generalization, in adults with epilepsy and as adjunctive therapy in the treatment of partial and generalized seizures associated with Lennox-Gastaut syndrome in children.
DOSAGE AND ADMINISTRATION
Felbatol® (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 Felbatol® is added to or substituted for existing AEDs, it is strongly recommended to reduce the dosage of those AEDs in the range of 20-33% 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. In the renally impaired, starting and maintenance doses should be reduced by one-half (see CLINICAL PHARMACOLOGY / Pharmacokinetics and PRECAUTIONS). Adjunctive therapy with medications which affect felbamate plasma concentrations, especially AEDs, may warrant further reductions in felbamate daily doses in patients with renal dysfunction.
Adults (14 years of age and over)
The majority of patients received 3600 mg/day in clinical trials evaluating its use as both monotherapy and adjunctive therapy.
Monotherapy: (Initial therapy) Felbatol® (felbamate) has not been systematically evaluated as initial monotherapy. Initiate Felbatol® at 1200 mg/day in divided doses three or four times daily. The prescriber is advised to titrate previously untreated patients under close clinical supervision, increasing the dosage in 600-mg increments every 2 weeks to 2400 mg/day based on clinical response and thereafter to 3600 mg/day if clinically indicated.
Conversion to Monotherapy: Initiate Felbatol® at 1200 mg/day in divided doses three or four times daily. Reduce the dosage of concomitant AEDs by one-third at initiation of Felbatol® therapy. At week 2, increase the Felbatol® dosage to 2400 mg/day while reducing the dosage of other AEDs up to an additional one-third of their original dosage. At week 3, increase the Felbatol® dosage up to 3600 mg/day and continue to reduce the dosage of other AEDs as clinically indicated.
Adjunctive Therapy: Felbatol® should be added at 1200 mg/day in divided doses three or four times daily while reducing present AEDs by 20% in order to control plasma concentrations of concurrent phenytoin, valproic acid, phenobarbital, and carbamazepine and its metabolites. Further reductions of the concomitant AEDs dosage may be necessary to minimize side effects due to drug interactions. Increase the dosage of Felbatol® by 1200 mg/day increments at weekly intervals to 3600 mg/day. Most side effects seen during Felbatol® adjunctive therapy resolve as the dosage of concomitant AEDs is decreased.
Table 6: Dosage Table (adults)
|WEEK1||WEEK 2||WEEK 3|
|Dosage reduction of concomitant AEDs||REDUCE original dose by 20-33%*||REDUCE original dose by up to an additional 1/3*||REDUCE as clinically indicated|
|Felbatol® Dosage||1200 mg/day Initial dose||2400 mg/day Therapeutic dosage range||3600 mg/day Therapeutic dosage range|
|*See Adjunctive and Conversion to Monotherapy sections.|
While the above Felbatol® conversion guidelines may result in a Felbatol® 3600 mg/day dose within 3 weeks, in some patients titration to a 3600 mg/day Felbatol® dose has been achieved in as little as 3 days with appropriate adjustment of other AEDs.
Children with Lennox-Gastaut Syndrome (Ages 2-14 years)
Adjunctive Therapy: Felbatol® should be added at 15 mg/kg/day in divided doses three or four times daily while reducing present AEDs by 20% in order to control plasma levels of concurrent phenytoin, valproic acid, phenobarbital, and carbamazepine and its metabolites. Further reductions of the concomitant AEDs dosage may be necessary to minimize side effects due to drug interactions. Increase the dosage of Felbatol® by 15 mg/kg/day increments at weekly intervals to 45 mg/kg/day. Most side effects seen during Felbatol® adjunctive therapy resolve as the dosage of concomitant AEDs is decreased.
Felbatol® (felbamate) Tablets, 400 mg, are yellow, scored, capsule-shaped tablets, debossed 0430 on one side and FELBATOL 400 on the other; available in bottles of 100 (NDC 0037-0430-01). Felbatol® (felbamate) Tablets, 600 mg, are peach-colored, scored, capsule-shaped tablets, debossed 0431 on one side and FELBATOL 600 on the other; available in bottles of 100 (NDC 0037-0431-01). Felbatol® (felbamate) Oral Suspension, 600 mg/5 mL, is peach-colored; available in 8 oz bottles (NDC 0037-0442-67) and 32 oz bottles (NDC 0037-0442-17).
Shake suspension well before using. Store at controlled room temperature 20°-25°C (68°-77°F). Dispense in tight container.
To report SUSPECTED ADVERSE REACTIONS, contact Meda Pharmaceuticals Inc. at 1-800-526-3840 or FDA at 1-800-FDA-1088 or www.fda.sov/medwatch.
MEDA Pharmaceuticals Inc. Somerset, NJ 08873. Rev. 7/11
Last reviewed on RxList: 9/17/2012
This monograph has been modified to include the generic and brand name in many instances.
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