What is Felbamate?

Felbamate use is associated with a marked increase in the incidence of aplastic anemia, sometimes fatal. Discontinue if any evidence of bone marrow depression occurs. Liver failure resulting in death or transplant has been reported with therapy. Felbamate should not be prescribed for anyone with a history of hepatic dysfunction and should be discontinued in anyone showing signs of liver injury while on therapy. Monitor liver enzymes during therapy .

Felbamate is used alone or together with other medicines to control partial seizures (convulsions) in the treatment of epilepsy, after other therapies have failed or are not right for the patient. It is also used in children to control partial and generalized seizures caused by Lennox-Gastaut syndrome.

Felbamate belongs to a class of medicines called anticonvulsants. It acts in the brain to prevent seizures. However, this medicine cannot cure epilepsy and will only work to control seizures for as long as you continue to take it.

This medicine is available only with your doctor's prescription.

This medicine should not be the first medicine you use to treat your condition. It is meant to be used only after you have tried other medicines that have not worked or have caused unwanted side effects.

Take this medicine only as directed by your doctor, to benefit your condition as much as possible. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

It is very important that you understand the risks and benefits of felbamate before using it. You may also be asked to sign a patient/physician acknowledgment form and read the Medication Guide to make sure you understand the information about this medicine. Be sure to ask your doctor about anything you do not understand.

For patients taking the oral liquid form of this medicine:

• Shake the bottle well before measuring the dose.
• Use a specially marked measuring spoon, a plastic syringe, or a small marked measuring cup to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

To lessen stomach upset, felbamate may be taken with food, unless your doctor has told you to take it on an empty stomach.

This medicine can be used with other seizure medicines. Keep using all of your seizure medicines unless your doctor tells you to stop.

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage forms (suspension or tablets):
  • For epilepsy:
    • Adults and teenagers 14 years of age and older—At first, usually 1200 milligrams (mg) per day, divided into three or four smaller doses. Your doctor may gradually increase your dose over several weeks up to 3600 mg per day.
    • Children—Use and dose must be determined by your doctor.
  • For Lennox-Gastaut syndrome:
    • Adults and teenagers 14 years of age and older—At first, usually 1200 milligrams (mg) per day, divided into three or four smaller doses. Your doctor may gradually increase your dose over several weeks up to 3600 mg per day.
    • Children 2 to 14 years of age—Dose is based on body weight and must be determined by your doctor. The starting dose is usually 15 mg per kilogram (kg) of body weight per day, divided into three or four smaller doses. Your doctor may gradually increase the dose over a few weeks up to 45 mg per kg of body weight per day.
    • Children younger than 2 years of age—Use and dose must be determined by your doctor.

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Appropriate studies have not been performed on the relationship of age to the effects of felbamate to treat seizures other than Lennox-Gastaut syndrome in children. Safety and efficacy have not been established.

Although appropriate studies on the relationship of age to the effects of felbamate have not been performed in the geriatric population, no geriatric-specific problems have been documented to date. However, elderly patients are more likely to have age-related heart, kidney, or liver problems, which may require caution and an adjustment in the dose for patients receiving felbamate.

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Amifampridine
• Amisulpride
• Bepridil
• Cisapride
• Dronedarone
• Mesoridazine
• Pimozide
• Piperaquine
• Saquinavir
• Sparfloxacin
• Terfenadine
• Thioridazine
• Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Amiodarone
• Anagrelide
• Aripiprazole
• Aripiprazole Lauroxil
• Arsenic Trioxide
• Buprenorphine
• Buserelin
• Calcifediol
• Citalopram
• Clarithromycin
• Clopidogrel
• Clozapine
• Crizotinib
• Dabrafenib
• Dasatinib
• Degarelix
• Delamanid
• Deslorelin
• Deutetrabenazine
• Domperidone
• Donepezil
• Efavirenz
• Encorafenib
• Escitalopram
• Fingolimod
• Fluconazole
• Fluoxetine
• Foscarnet
• Gestodene
• Gonadorelin
• Goserelin
• Histrelin
• Hydroxychloroquine
• Hydroxyzine
• Inotuzumab Ozogamicin
• Ivabradine
• Ivosidenib
• Ketoconazole
• Leuprolide
• Levofloxacin
• Lofexidine
• Macimorelin
• Methadone
• Metronidazole
• Moxifloxacin
• Nafarelin
• Nilotinib
• Ondansetron
• Orlistat
• Osimertinib
• Panobinostat
• Pasireotide
• Pazopanib
• Pimavanserin
• Pitolisant
• Posaconazole
• Quetiapine
• Ribociclib
• Sertraline
• Sevoflurane
• Sotalol
• Sulpiride
• Tacrolimus
• Triptorelin
• Vandetanib
• Vemurafenib
• Vinflunine
• Zuclopenthixol

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Carbamazepine
• Clobazam
• Fosphenytoin
• Ginkgo
• Methsuximide
• Phenytoin
• Valproic Acid
• Warfarin

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Blood problems (e.g., aplastic anemia), history of or
• Liver problems, history of—Should not be used in patients with these conditions.

• Depression or
• Mental illness—Use with caution. May make these conditions worse.

• Kidney disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

It is very important that your doctor check the progress of you or your child at regular visits. This is necessary to allow dose adjustments and to check for serious unwanted effects.

It is important to tell your doctor if you become pregnant. Your doctor may want you to join the North American Antiepileptic Drug Pregnancy Registry, which is used by pregnant patients who are taking this medicine.

Felbamate has caused a few cases of a serious blood disorder called aplastic anemia and a few cases of liver failure. Talk to your doctor about these risks.

Stop using this medicine and check with your doctor right away if you or your child have pain or tenderness in the upper stomach; pale stools; dark urine; loss of appetite; nausea; unusual tiredness or weakness; or yellow eyes or skin. These could be symptoms of a serious liver problem.

Tell your doctor right away if you or your child has chest pain; chills; cough; fever; headache; shortness of breath; sores, ulcers, or white spots on lips or in mouth; swollen or painful glands; tightness in chest; unusual bleeding or bruising; unusual tiredness or weakness; or wheezing. These could be symptoms of aplastic anemia.

Do not stop taking felbamate without first checking with your doctor. Your doctor may want you to gradually reduce the amount you or your child are taking before stopping completely. Stopping the medicine suddenly may cause your seizures to return or to occur more often.

If you or your child develop any unusual or strange thoughts and behavior while taking this medicine, be sure to discuss it with your doctor. Other changes might be confusion, worsening of depression, hallucinations (seeing, hearing, or feeling things that are not there), suicidal thoughts, and unusual excitement, nervousness, or irritability.

Felbamate may cause blurred vision, double vision, or other changes in vision. It may also cause some people to become dizzy or drowsy. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert or able to see well. If these reactions are especially bothersome, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.