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Felbatol (Felbamate) - Summary

 
 



WARNING

1. APLASTIC ANEMIA
THE USE OF FELBATOL® (felbamate) IS ASSOCIATED WITH A MARKED INCREASE IN THE INCIDENCE OF APLASTIC ANEMIA. ACCORDINGLY, FELBATOL® 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 FELBATOL® WITHOUT CONSIDERATION OF APPROPRIATE EXPERT HEMATOLOGIC CONSULTATION.

AMONG FELBATOL® TREATED PATIENTS, APLASTIC ANEMIA (PANCYTOPENIA IN THE PRESENCE OF A BONE MARROW LARGELY DEPLETED OF HEMATOPOIETIC PRECURSORS) OCCURS AT AN INCIDENCE THAT MAY BE MORE THAN A 100 FOLD GREATER THAN THAT SEEN IN THE UNTREATED POPULATION (I.E., 2 TO 5 PER MILLION PERSONS PER YEAR). THE RISK OF DEATH IN PATIENTS WITH APLASTIC ANEMIA GENERALLY VARIES AS A FUNCTION OF ITS SEVERITY AND ETIOLOGY; CURRENT ESTIMATES OF THE OVERALL CASE FATALITY RATE ARE IN THE RANGE OF 20 TO 30%, BUT RATES AS HIGH AS 70% HAVE BEEN REPORTED IN THE PAST.

THERE ARE TOO FEW FELBATOL® ASSOCIATED CASES, AND TOO LITTLE KNOWN ABOUT THEM TO PROVIDE A RELIABLE ESTIMATE OF THE SYNDROME'S INCIDENCE OR ITS CASE FATALITY RATE OR TO IDENTIFY THE FACTORS, IF ANY, THAT MIGHT CONCEIVABLY BE USED TO PREDICT WHO IS AT GREATER OR LESSER RISK.

IN MANAGING PATIENTS ON FELBATOL®, IT SHOULD BE BORNE IN MIND THAT THE CLINICAL MANIFESTATION OF APLASTIC ANEMIA MAY NOT BE SEEN UNTIL AFTER A PATIENT HAS BEEN ON FELBATOL® FOR SEVERAL MONTHS (E.G., ONSET OF APLASTIC ANEMIA AMONG FELBATOL® EXPOSED PATIENTS FOR WHOM DATA ARE AVAILABLE HAS RANGED FROM 5 TO 30 WEEKS). HOWEVER, THE INJURY TO BONE MARROW STEM CELLS THAT IS HELD TO BE ULTIMATELY RESPONSIBLE FOR THE ANEMIA MAY OCCUR WEEKS TO MONTHS EARLIER. ACCORDINGLY, PATIENTS WHO ARE DISCONTINUED FROM FELBATOL® REMAIN AT RISK FOR DEVELOPING ANEMIA FOR A VARIABLE, AND UNKNOWN, PERIOD AFTERWARDS.

IT IS NOT KNOWN WHETHER OR NOT THE RISK OF DEVELOPING APLASTIC ANEMIA CHANGES WITH DURATION OF EXPOSURE. CONSEQUENTLY, IT IS NOT SAFE TO ASSUME THAT A PATIENT WHO HAS BEEN ON FELBATOL® WITHOUT SIGNS OF HEMATOLOGIC ABNORMALITY FOR LONG PERIODS OF TIME IS WITHOUT RISK.

IT IS NOT KNOWN WHETHER OR NOT THE DOSE OF FELBATOL® AFFECTS THE INCIDENCE OF APLASTIC ANEMIA.

IT IS NOT KNOWN WHETHER OR NOT CONCOMITANT USE OF ANTIEPILEPTIC DRUGS AND/OR OTHER DRUGS AFFECTS THE INCIDENCE OF APLASTIC ANEMIA.

APLASTIC ANEMIA TYPICALLY DEVELOPS WITHOUT PREMONITORY CLINICAL OR LABORATORY SIGNS, THE FULL BLOWN SYNDROME PRESENTING WITH SIGNS OF INFECTION, BLEEDING, OR ANEMIA. ACCORDINGLY, ROUTINE BLOOD TESTING CANNOT BE RELIABLY USED TO REDUCE THE INCIDENCE OF APLASTIC ANEMIA, BUT, IT WILL, IN SOME CASES, ALLOW THE DETECTION OF THE HEMATOLOGIC CHANGES BEFORE THE SYNDROME DECLARES ITSELF CLINICALLY. FELBATOL® SHOULD BE DISCONTINUED IF ANY EVIDENCE OF BONE MARROW DEPRESSION OCCURS.

2. HEPATIC FAILURE
EVALUATION OF POSTMARKETING EXPERIENCE SUGGESTS THAT ACUTE LIVER FAILURE IS ASSOCIATED WITH THE USE OF FELBATOL®. THE REPORTED RATE IN THE U.S. HAS BEEN ABOUT 6 CASES OF LIVER FAILURE LEADING TO DEATH OR TRANSPLANT PER 75,000 PATIENT YEARS OF USE. THIS RATE IS AN UNDERESTIMATE BECAUSE OF UNDER REPORTING, AND THE TRUE RATE COULD BE CONSIDERABLY GREATER THAN THIS. FOR EXAMPLE, IF THE REPORTING RATE IS 10%, THE TRUE RATE WOULD BE ONE CASE PER 1,250 PATIENT YEARS OF USE.

OF THE CASES REPORTED, ABOUT 67% RESULTED IN DEATH OR LIVER TRANSPLANTATION, USUALLY WITHIN 5 WEEKS OF THE ONSET OF SIGNS AND SYMPTOMS OF LIVER FAILURE. THE EARLIEST ONSET OF SEVERE HEPATIC DYSFUNCTION FOLLOWED SUBSEQUENTLY BY LIVER FAILURE WAS 3 WEEKS AFTER INITIATION OF FELBATOL®. ALTHOUGH SOME REPORTS DESCRIBED DARK URINE AND NONSPECIFIC PRODROMAL SYMPTOMS (E.G., ANOREXIA, MALAISE, AND GASTROINTESTINAL SYMPTOMS), IN OTHER REPORTS IT WAS NOT CLEAR IF ANY PRODROMAL SYMPTOMS PRECEDED THE ONSET OF JAUNDICE.

IT IS NOT KNOWN WHETHER OR NOT THE RISK OF DEVELOPING HEPATIC FAILURE CHANGES WITH DURATION OF EXPOSURE.

IT IS NOT KNOWN WHETHER OR NOT THE DOSAGE OF FELBATOL® AFFECTS THE INCIDENCE OF HEPATIC FAILURE.

IT IS NOT KNOWN WHETHER CONCOMITANT USE OF OTHER ANTIEPILEPTIC DRUGS AND/OR OTHER DRUGS AFFECT THE INCIDENCE OF HEPATIC FAILURE.

FELBATOL® SHOULD NOT BE PRESCRIBED FOR ANYONE WITH A HISTORY OF HEPATIC DYSFUNCTION.

TREATMENT WITH FELBATOL® SHOULD BE INITIATED ONLY IN INDIVIDUALS WITHOUT ACTIVE LIVER DISEASE AND WITH NORMAL BASELINE SERUM TRANSAMINASES. IT HAS NOT BEEN PROVED THAT PERIODIC SERUM TRANSAMINASE TESTING WILL PREVENT SERIOUS INJURY BUT IT IS GENERALLY BELIEVED THAT EARLY DETECTION OF DRUG-INDUCED HEPATIC INJURY ALONG WITH IMMEDIATE WITHDRAWAL OF THE SUSPECT DRUG ENHANCES THE LIKELIHOOD FOR RECOVERY. THERE IS NO INFORMATION AVAILABLE THAT DOCUMENTS HOW RAPIDLY PATIENTS CAN PROGRESS FROM NORMAL LIVER FUNCTION TO LIVER FAILURE, BUT OTHER DRUGS KNOWN TO BE HEPATOTOXINS CAN CAUSE LIVER FAILURE RAPIDLY (E.G., FROM NORMAL ENZYMES TO LIVER FAILURE IN 2-4 WEEKS). ACCORDINGLY, MONITORING OF SERUM TRANSAMINASE LEVELS (AST AND ALT) IS RECOMMENDED AT BASELINE AND PERIODICALLY THEREAFTER. WHILE THE MORE FREQUENT THE MONITORING THE GREATER THE CHANCES OF EARLY DETECTION, THE PRECISE SCHEDULE FOR MONITORING IS A MATTER OF CLINICAL JUDGEMENT.

FELBATOL® SHOULD BE DISCONTINUED IF EITHER SERUM AST OR SERUM ALT LEVELS BECOME INCREASED ≥ 2 TIMES THE UPPER LIMIT OF NORMAL, OR IF CLINICAL SIGNS AND SYMPTOMS SUGGEST LIVER FAILURE (SEE PRECAUTIONS). PATIENTS WHO DEVELOP EVIDENCE OF HEPATOCELLULAR INJURY WHILE ON FELBATOL® AND ARE WITHDRAWN FROM THE DRUG FOR ANY REASON SHOULD BE PRESUMED TO BE AT INCREASED RISK FOR LIVER INJURY IF FELBATOL® IS REINTRODUCED. ACCORDINGLY, SUCH PATIENTS SHOULD NOT BE CONSIDERED FOR RE-TREATMENT.

 

FELBATOL SUMMARY

Felbatol® (felbamate) is an antiepileptic available as 400 mg and 600 mg tablets and as a 600 mg/5 mL suspension for oral administration.

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, informed consent, 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.


See all Felbatol indications & dosage >>

NEWS HIGHLIGHTS

Media Articles Related to Felbatol (Felbamate)

Could listening to music help treat epilepsy?
Source: Epilepsy News From Medical News Today [2015.08.10]
Researchers from Ohio State University found the brains of people with epilepsy respond differently to music, suggesting music could be used to help treat the disorder.

Music Therapy Might Help People With Epilepsy
Source: MedicineNet Seizure Specialty [2015.08.10]
Title: Music Therapy Might Help People With Epilepsy
Category: Health News
Created: 8/10/2015 12:00:00 AM
Last Editorial Review: 8/10/2015 12:00:00 AM

New evidence linking brain mutation to autism, epilepsy and other neuro disorders
Source: Epilepsy News From Medical News Today [2015.07.16]
Findings, published 15 July in Nature Communications, reveal the extent a mutation associated with autism and epilepsy plays in impairing a biochemical process in the brain.

Prion protein protects against epilepsy
Source: Epilepsy News From Medical News Today [2015.07.09]
Neuroprotective role of PrPC confirmed with unprecedented accuracyThis is the prion protein. Credit: G. Giachin & G.

Epilepsy 'increases risk of death' among pregnant women
Source: Epilepsy News From Medical News Today [2015.07.07]
Pregnant women with epilepsy may be at 10 times greater risk of maternal death and adverse complications during delivery than those without the disorder, a new study finds.

more news >>

Published Studies Related to Felbatol (Felbamate)

Felbamate as an add-on therapy for refractory epilepsy. [2014]
CONCLUSIONS: In view of the methodological deficiencies, limited number

Felbamate as an add-on therapy for refractory epilepsy. [2011.01.19]
CONCLUSIONS: In view of the methodological deficiencies, limited number of individual studies and differences in outcome measure, we have found no reliable evidence to support the use of felbamate as an add-on therapy in patients with refractory partial-onset epilepsy. A large scale, randomized controlled trial conducted over a greater period of time is required to inform clinical practice.

Felbamate as an add-on therapy for refractory epilepsy. [2011]
CONCLUSIONS: In view of the methodological deficiencies, limited number

Low dose of bupropion significantly enhances the anticonvulsant activity of felbamate, lamotrigine and topiramate in mice. [2011.01.15]
Experimental evidence indicates that bupropion hydrochloride, an antidepressant and a first-line smoking cessation aid, exerts dose-dependently anticonvulsant and convulsant effects.A pharmacokinetic interaction is responsible for the effect of bupropion co-administered with lamotrigine.

[Felbamate crystalluria]. [2010.09]
This report describes the case of an 11-year-old child, who presents crystalluria occurring after several years of treatment with antiepileptic felbamate (Taloxa(R)). The crystalline morphologies observed were very heterogeneous, long and thin needle shapped-crystals or even hairy crystals or large needle asymmetric crystals...

more studies >>

Clinical Trials Related to Felbatol (Felbamate)

Clinical Trial of Felbamate for Treatment-Resistant Bipolar Depression [Completed]
The purpose of this study is to evaluate the safety and effectiveness of the drug felbamate for treating depression in patients with bipolar disorder that has not responded to standard treatments. Bipolar disorder is a severe, chronic, and often life-threatening illness. Despite the availability of a wide range of antidepressant drugs, a proportion of patients fail to respond to first-line antidepressant treatment despite adequate dosage, duration, and compliance. Studies suggest that the glutamatergic system may play a role in the pathophysiology and treatment of depression. Felbamate and other agents which reduce glutamatergic neurotransmission may represent a novel class of antidepressants. Participants in this study will be admitted to the Clinical Center for up to 10 weeks. At study entry, participants will have a 7-day washout period in which they will be tapered off all psychiatric medications, with the possible exception of lithium, and will be given a placebo (an inactive pill). After the washout period, participants will be randomly assigned to receive either felbamate or placebo for 8 weeks. Participants whose depression symptoms worsen by more than 30% or those for whom study continuation is considered potentially harmful will be taken off the study and offered open-label treatment. Participants who received felbamate and responded well to treatment will have the option of continuing treatment.

Clinical and Economic Burden of Uncontrolled Epilepsy: Analyses From a Medicaid Database and a Private Health Plan Database [Completed]
Antiepileptic drugs (AEDs) are the main therapeutic option for patients with epilepsy; however, complete seizure control remains elusive for many patients. Uncontrolled or refractory epilepsy is associated with a higher risk of mortality, physical injuries, and depression or anxiety compared with patients with controlled epilepsy. Higher resource utilization for patients with poor control is likely to be associated with higher economic costs. While diagnostic criteria for uncontrolled epilepsy are debated by neurologists, recent studies suggest that a diagnosis of uncontrolled epilepsy requires 1.) at least one seizure per month and 2.) a history of drug failures. The objective of this study is to identify patients with uncontrolled epilepsy in both a Medicaid database and a private health plan database, to describe patient characteristics and AED treatment patterns between cohorts of patients with uncontrolled versus well-controlled epilepsy, and to evaluate the economic burden of uncontrolled versus well-controlled epilepsy. For this evaluation, the data sources are medical and pharmacy claims in Medicaid databases from Florida (Third quarter 1997 to second quarter 2008), Iowa (First quarter 1998 to second quarter 2006), Kansas (First quarter 2001 to second quarter 2009), Missouri (First quarter 1997 to second quarter 2008) and New Jersey (First quarter 1997 to fourth quarter 2008) and medical and pharmacy claims in an private health plan database. The study design is a retrospective, longitudinal, matched-cohort study. Eligible patient records will be assigned to one of three mutually-exclusive cohorts: uncontrolled epilepsy (at least 2 consecutive changes in AED therapy in at least 30 days, and at least 1 epilepsy-related inpatient or emergency department (ED) visit within 365 days), well-controlled epilepsy (no AED changes and no epilepsy-related inpatient or ED visits), and intermediate epilepsy (not classified as uncontrolled or well-controlled).

Tetra-O-Methyl Nordihydroguaiaretic Acid in Treating Patients With Recurrent High-Grade Glioma [Completed]
RATIONALE: Drugs used in chemotherapy, such as tetra-O-methyl nordihydroguaiaretic acid (EM-1421), work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. PURPOSE: This phase I/II trial is studying the side effects and best dose of EM-1421 and to see how well it works in treating patients with recurrent high-grade glioma.

Ketogenic Diet vs.Antiepileptic Drug Treatment in Drug Resistant Epilepsy [Active, not recruiting]
This is an open randomized controlled study in children with mental retardation and refractory epilepsy in which treatment with ketogenic diet (KD) is compared with treatment with the antiepileptic drug (AED), not tried by the patient before, which we consider to be the most appropriate AED for the patient.

more trials >>

Reports of Suspected Felbatol (Felbamate) Side Effects

Grand MAL Convulsion (7)Decreased Appetite (6)Convulsion (6)Weight Decreased (5)Gastrooesophageal Reflux Disease (5)Condition Aggravated (4)Product Substitution Issue (3)Pyrexia (3)Constipation (3)Treatment Noncompliance (3)more >>


Page last updated: 2015-08-10

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