Felbamate (Page 5 of 6)
DRUG ABUSE AND DEPENDENCE
Abuse potential was not evaluated in human studies.
Rats administered felbamate orally at doses 8.3 times the recommended human dose 6 days each week for 5 consecutive weeks demonstrated no signs of physical dependence as measured by weight loss following drug withdrawal on day 7 of each week.
Four subjects inadvertently received felbamate as adjunctive therapy in dosages ranging from 5400 to 7200 mg/day for durations between 6 and 51 days. One subject who received 5400 mg/day as monotherapy for 1 week reported no adverse experiences. Another subject attempted suicide by ingesting 12,000 mg of felbamate in a 12-hour period. The only adverse experiences reported were mild gastric distress and a resting heart rate of 100 bpm. No serious adverse reactions have been reported. General supportive measures should be employed if overdosage occurs. It is not known if felbamate is dialyzable.
DOSAGE AND ADMINISTRATION
Felbamate tablets have been studied as monotherapy and adjunctive therapy in adults and as adjunctive therapy in children with seizures associated with Lennox-Gastaut syndrome. As felbamate tablets are 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. 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) Felbamate tablets have not been systematically evaluated as initial monotherapy. Initiate felbamate tablets 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 felbamate tablets at 1200 mg/day in divided doses three or four times daily. Reduce the dosage of concomitant AEDs by one-third at initiation of felbamate tablets therapy. At week 2, increase the felbamate tablets 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 felbamate tablets dosage up to 3600 mg/day and continue to reduce the dosage of other AEDs as clinically indicated.
Adjunctive Therapy: Felbamate tablets 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 felbamate tablets by 1200 mg/day increments at weekly intervals to 3600 mg/day. Most side effects seen during felbamate tablets adjunctive therapy resolve as the dosage of concomitant AEDs is decreased.
Table 6 Dosage Table (adults)
Dosage reduction of concomitant AEDs
WEEK 1 REDUCE original dose by 20 to 33%*
WEEK 2 REDUCE original dose by up to an additional 1/3*
WEEK 3 REDUCE as clinically indicated
Felbamate Tablets 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 felbamate tablets conversion guidelines may result in a felbamate tablets 3600 mg/day dose within 3 weeks, in some patients titration to a 3600 mg/day felbamate tablets dose has been achieved in as little as 3 days with appropriate adjustment of other AEDs.
Children with Lennox-Gastaut Syndrome (Ages 2 to 14 years)
Adjunctive Therapy: Felbamate tablets 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 felbamate tablets by 15 mg/kg/day increments at weekly intervals to 45 mg/kg/day. Most side effects seen during felbamate tablets adjunctive therapy resolve as the dosage of concomitant AEDs is decreased.
Felbamate Tablets USP, 400 mg, are light yellow to yellow, capsule shaped tablets debossed ‘ANI 730’ on one side and bisect on the other side.
Bottles of 100 NDC 63629-1937-1
Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Dispense in tight container.
To report SUSECTED ADVERSE REACTIONS, contact ANI Pharmaceuticals, Inc. at 1-800-308-6755 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
PATIENT/PHYSICIAN ACKNOWLEDGMENT FORM
FELBAMATE SHOULD NOT BE USED BY PATIENTS UNTIL THERE HAS BEEN A COMPLETE DISCUSSION OF THE RISKS.
All patients treated with felbamate should acknowledge that they understand the risks and other information about felbamate discussed below, and physicians should acknowledge this discussion.
IMPORTANT INFORMATION AND WARNING:
Felbamate, taken by itself or with other prescription and/or non-prescription drugs, can result in a severe, potentially fatal blood abnormality (“aplastic anemia”) and/or severe, potentially fatal liver damage.
Do not sign this form if there is anything you do not understand about the information you have received. Ask your doctor about anything you do not understand before you initial any of the items below or sign this form.
My [My son, daughter, ward ‘s] treatment with felbamate has been personally explained to me by Dr.. The following points of information, among others, have been specifically discussed and made clear and I have had the opportunity to ask any questions concerning this information:
1. I, (Patient’s Name), understand that felbamate is used to treat certain types of seizures and my physician has told me that I have this type(s) of seizures;
2. I understand that felbamate is being used because my seizures have not been satisfactorily treated with other antiepileptic drugs;
3. I understand that there is a serious risk that I could develop aplastic anemia and/or liver failure, both of which are potentially fatal, by using felbamate;
4. I understand that there are no laboratory tests which will predict if I am at an increased risk for one of the potentially fatal conditions;
5. I understand that I should have the recommended blood work before my treatment with felbamate is begun (baseline) and periodically thereafter as clinical judgement warrants. I understand that although this blood work may help detect if I develop one of these conditions, it may do so only after significant, irreversible and potentially fatal damage has already occurred;
6. If I am currently taking other antiepileptic drugs, I understand that the manufacturer of felbamate recommends that the dosage of these other drugs be decreased by a certain amount when felbamate is started; if my physician determines that this should not be done in my case, he/she has explained the reason(s) for this decision;
7. I understand that I must immediately report any unusual symptoms to Dr. and be especially aware of any rashes, easy bruising, bleeding, sore throats, fever, and/or dark urine;
8. I understand that antiepileptic drugs such as felbamate may increase the risk of suicidal thoughts and behavior. I understand that I must immediately report any unusual changes in mood or behavior, symptoms of depression or thoughts about self-harm to Dr. .
Patient, Parent, or Guardian
I have fully explained to the patient, , the nature and purpose of the treatment with felbamate and the potential risks associated with that treatment. I have asked the patient if he/she has any questions regarding this treatment or the risks and have answered those questions to the best of my ability. I also acknowledge that I have read and understand the prescribing information.
NOTE TO PHYSICIAN: It is strongly recommended that you retain a signed copy of the Patient/Physician Acknowledgment Form with the patient’s medical records.
SUPPLY OF PATIENT/PHYSICIAN ACKNOWLEDGMENT FORMS:
A supply of “Patient/Physician Acknowledgment” Forms as printed above is available, free of charge, on our website, www.anipharmaceuticals.com, or may be obtained by calling our Customer Service Representatives at 1-800-434-1121. Permission to use the above Patient/Physician Acknowledgment Form by photocopy reproduction is also hereby granted by ANI Pharmaceuticals, Inc.
Bora Pharmaceutical Laboratories Inc.
ANI Pharmaceuticals, Inc.
Baudette, MN 56623
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