Felbamate

By Medically reviewed by hellodoktor

Generic Name: Felbamate Brand Name(s): Felbamate, Felbamate and Felbamate.

Uses

What is Felbamate used for?

Felbamate is commonly used to treat severe seizures. This medication should be used only when you cannot take other medications or when other medications have not been able to control your seizures. Felbamate is known as an anticonvulsant or anti-epileptic drug.

How should I take Felbamate?

Take this medication by mouth with or without food as directed by your doctor, usually 3 to 4 times a day. Take with food or milk if stomach upset occurs.

If you are using the liquid form of this medication, shake the bottle well before each dose. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

The dosage is based on your medical condition and response to treatment. For children, the dosage is also based on weight. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose.

Take this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

Do not stop taking this medication without consulting your doctor. Seizures may become worse when this drug is suddenly stopped. Your dose may need to be gradually decreased.

If you are already taking other anti-seizure medications, carefully follow your doctor’s directions for adjusting the dose of these other medications when you start taking felbamate.

Tell your doctor if your seizures get worse.

How do I store Felbamate?

Felbamate is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Felbamate in the bathroom or the freezer. There may be different brands of Felbamate that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Felbamate down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Felbamate?

Before taking felbamate, tell your doctor or pharmacist if you are allergic to it; or to meprobamate; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood/bone marrow disorders (such as anemia, bleeding problems, low white blood cell count), liver disease, kidney disease, mental/mood disorders (such as depression, suicidal thoughts).

This drug may make you dizzy or drowsy or blur your vision. It may also cause double vision. Alcohol or marijuana can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially dizziness, loss of coordination, or fainting. These side effects can increase the risk of falling.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Felbamate during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Felbamate. Felbamate is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Felbamate?

Drowsiness, dizziness, nausea, vomiting, diarrhea, constipation, trouble sleeping, loss of coordination, headache, blurred/double vision, hiccups, or loss of appetite may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Felbamate?

Some products that may interact with this drug include: clopidogrel, orlistat.

This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use reliable backup birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.

Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana, antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), and narcotic pain relievers (such as codeine, hydrocodone).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

Felbamate may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Felbamate?

Felbamate may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Felbamate?

Felbamate may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Felbamate.

What is the dose of Felbamate for an adult?

Usual Adult Dose for Epilepsy

Monotherapy:

-Initial dose: 1200 mg orally daily in 3 to 4 divided doses

-Maintenance dose: Titrate previously untreated patients by increasing the dose in 600 mg increments every 2 weeks to 2400 mg orally daily in 3 to 4 divided doses based on clinical response and thereafter to 3600 mg orally daily in 3 to 4 divided doses if clinically indicated

-Maximum dose: 3600 mg orally daily in 3 to 4 divided doses

Conversion to monotherapy:

-Initial dose: 1200 mg orally daily in 3 to 4 divided doses; reduce the dose of concomitant antiepileptic drugs (AEDs) by 33% at the initiation of this drug

-Maintenance dose: At week 2, increase the dose to 2400 mg orally daily in 3 to 4 divided doses and reduce the dosage of other AEDs up to an additional 33% of the original dose; at week 3, increase the dose to 3600 mg orally daily in 3 to 4 divided doses and continue to reduce the dose of other AEDs as clinically indicated

-Maximum dose: 3600 mg orally daily in 3 to 4 divided doses

Adjunctive therapy:

-Initial dose: 1200 mg orally daily in 3 to 4 divided doses; reduce the dose of other AEDs by 20%; further dose reductions of concomitant AEDs may be necessary to minimize side effects

-Maintenance dose: Increase dose by 1200 mg increments at weekly intervals to 3600 mg orally daily in 3 to 4 divided doses

-Maximum dose: 3600 mg orally daily in 3 to 4 divided doses

Comments:

-In some patients, titration to a 3600 mg/day dose has been achieved in as little as 3 days with appropriate adjustment of other AEDs.

Use: For use as monotherapy or adjunctive therapy in children 14 years of age and older and adults in the treatment of partial seizures, with and without generalization (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)

Renal Dose Adjustments

Use with caution.

Liver Dose Adjustments

Contraindicated

Precautions

APLASTIC ANEMIA:

-This drug is associated with a marked increase in the incidence of aplastic anemia; therefore, use only in patients with epilepsy so severe that the risk is acceptable because of the benefit of its use.

-Obtain an expert hematologic consultation before therapy is initiated.

-Aplastic anemia (pancytopenia in the presence of a bone marrow largely depleted of hematopoietic precursors) occurs at more than a 100-fold greater incidence in patients taking this drug is than in untreated patients (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 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 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.

-Aplastic anemia may not be seen until after a patient has been on this drug for several months (e.g., 5 to 30 weeks); however, the injury to bone marrow stem cells may occur weeks to months earlier. Patients who discontinue therapy remain at risk for developing anemia for an unknown period afterwards.

-It is not safe to assume that a patient who has been on this drug without signs of hematologic abnormality for long periods of time is without risk of developing aplastic anemia.

-It is not known whether or not the dose affects the incidence of aplastic anemia.

-It is not known whether or not concomitant use of AEDs and/or other drugs affects the incidence of aplastic anemia.

-Aplastic anemia typically develops without warning, the full blown syndrome presenting with signs of infection, bleeding, or anemia.

-Routine blood testing cannot reliably be used to reduce the incidence of aplastic anemia; however, in some cases, it allows the detection of the hematologic changes before the syndrome presents clinically.

-Therapy should be discontinued if any evidence of bone marrow depression occurs.

HEPATIC FAILURE

-This drug is associated with acute liver failure. The reported incidence is about 6 cases 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 (e.g., if the reporting rate is 10%, the true rate would be one case per 1250 patient years of use).

-About 67% of cases resulted in death or liver transplantation, usually within 5 weeks of the onset of liver failure.

-The earliest onset of severe hepatic dysfunction followed by liver failure was 3 weeks after initiation of therapy; however, some reports described dark urine and nonspecific warning symptoms (e.g., anorexia, malaise, GI symptoms). In other reports it was not clear if any warning symptoms preceded the onset of jaundice.

-It is not known if the risk of developing hepatic failure changes with duration of exposure.

-It is not known if the dosage of this drug affects the incidence of hepatic failure.

-It is not known if concomitant use of other AEDs and/or other drugs affect the incidence of hepatic failure.

-Do not prescribe this drug to anyone with a history of hepatic dysfunction.

-Initiate therapy only in patients without active liver disease and with normal baseline serum transaminases.

-It is unknown if periodic serum transaminase testing will prevent serious injury but early detection of drug-induced hepatic injury along with immediate withdrawal of therapy enhances the likelihood for recovery.

-It is unknown 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 to 4 weeks).

-Monitor serum transaminase levels (AST and ALT) at baseline and periodically thereafter; the schedule for monitoring is a matter of clinical judgement.

-Discontinue therapy if serum AST or ALT levels increase 2 times the upper limit of normal (ULN) or more, or if signs of liver failure are apparent.

-Patients who develop hepatocellular injury while on this drug and are withdrawn from therapy for any reason should be presumed to be at increased risk for liver injury if therapy is reintroduced; therefore, such patients should not be considered for retreatment.

Other Comments

Patient advice:

-Patients should be informed that this drug is associated with aplastic anemia and hepatic failure (potentially fatal conditions) either acutely or over the long term.

-Patients should be instructed to read the Medication Guide each time this drug is dispensed.

-Patients, their caregivers, and families should be counseled that AEDs may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.

What is the dose of Felbamate for a child?

Usual Pediatric Dose for Lennox-Gastaut Syndrome

Children 2 to 14 years with Lennox-Gastaut Syndrome:

Adjunctive therapy:

-Initial dose: 15 mg/kg/day orally in 3 to 4 divided doses; reduce the dose of concomitant AEDs by 20%; further dose reductions of concomitant AEDs may be necessary to minimize side effects

-Maintenance dose: Increase the dose by 15 mg/kg/day increments at weekly intervals as tolerated to desired clinical response

-Maximum dose: 45 mg/kg/day orally in 3 to 4 divided doses

Children 14 years of age and older:

Use adult dosing.

Use: For use as adjunctive therapy in the treatment of partial seizures and generalized seizures associated with Lennox-Gastaut syndrome in children (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)

Precautions

-Safety and efficacy have not been established in patients younger than 2 years for any indication.

-Safety and efficacy in patients younger than 14 years (other than those with Lennox-Gastaut syndrome) has not been established.

How is Felbamate available?

Felbamate is available in the following dosage forms and strengths:

  • Oral tablet
  • Oral suspension

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Felbamate, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Review Date: January 30, 2018 | Last Modified: September 12, 2019

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