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Overview: Felbamate is used to treat certain types of severe seizures. Common side effects include nausea, vomiting, loss of appetite, headache, drowsiness, and dizziness. Do not drive or do other activities that require alertness or coordination until you know how it affects you. This medicine can cause serious problems that may be life-threatening. Keep all appointments to have your blood checked even if this medicine is stopped by your health care provider.

Uses

What is felbamate used for?

Felbamate is used to treat certain types of severe seizures.

Felbamate may also be used for other conditions as determined by your health care provider.

How does felbamate work (mechanism of action)?

Seizures happen when too many nerve signals are sent between brain cells too quickly. Felbamate is thought to work by slowing down overactive brain signals and making seizures less likely.

How is felbamate supplied (dosage forms)?

Brands and other names

  • Felbatol

Dosage forms and strengths

  • 400 mg oral tablets
  • 600 mg oral tablets
  • 600 mg/5 mL oral suspension

How should I store felbamate?

Felbamate should be stored at room temperature, between 68 F and 77 F (20 C and 25 C).

Side Effects

What are the most common side effects of felbamate?

The most common side effects of felbamate are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Loss of appetite and weight loss
  • Nausea and vomiting
  • Trouble sleeping
  • Headache
  • Drowsiness
  • Dizziness
  • Double vision
  • Changes in how things taste

There may be other side effects of felbamate that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of felbamate?

While less common, the most serious side effects of felbamate are described below, along with what to do if they happen.

Blood Disorders. Felbamate can cause blood disorders, such as agranulocytosis, aplastic anemia, hemolytic anemia, low platelet levels (thrombocytopenia), and low white blood cell levels (leukopenia), which can be life-threatening. Keep all appointments to have your blood checked even if this medicine is stopped. Get help right away if you have any of the following symptoms of blood disorders.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Easy bruising or bleeding
  • Sore throat 
  • Frequent infection
  • Unusual weakness or tiredness
  • Dizziness, lightheadedness, or feeling like you are about to pass out
  • Headache
  • Fast or abnormal heartbeat

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking felbamate. Liver damage can be life-threatening. Keep all appointments to have your blood checked even if this medicine is stopped. Call your health care provider right away if you have any of the following symptoms.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Suicidal Thoughts and Actions. Felbamate may cause suicidal thoughts or actions in a small number of people. If you are about to harm yourself, call 911 or call or text 988, the Suicide & Crisis Lifeline. Call your health care provider right away if you have any of the following symptoms.

  • New or increased thoughts of suicide or death
  • Suicide attempt
  • New or increased feelings of anxiety, depression, or other unusual changes in mood or behavior

Severe Allergic Reactions. Felbamate may cause allergic reactions, which can be serious. Get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use felbamate?

Allergies to Ingredients. People who are allergic to any of the following should not take felbamate.

  • Felbamate
  • Felbatol
  • Any other medicine known as a carbamate
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific felbamate products they stock.

Blood Disorders. People with or a history of blood disorders, such as agranulocytosis, aplastic anemia, hemolytic anemia, low platelet levels (thrombocytopenia), and low white blood cell levels (leukopenia), should not use felbamate.

Liver Problems. Felbamate should not be used if your liver is not working as well as it should be. If there is a concern about the health of your liver, your health care provider may do tests to determine if it is working well enough to take this medicine.

What should I know about felbamate before using it?

Do not take felbamate unless it has been prescribed to you by a health care provider. Take it as prescribed.

If you are taking felbamate liquid, use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist to recommend an appropriate measuring device. Shake the medicine well before measuring each dose.

Do not share felbamate with other people, even if they have the same condition as you. It may harm them.

Keep felbamate out of the reach of children.

While felbamate helps make seizures less likely, it does not cure them. Do not stop taking felbamate without talking to your health care provider. Stopping felbamate suddenly may cause an increase in seizure activity, which can be serious.

Felbamate can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how felbamate affects you.

This medicine can cause serious problems with your blood and liver that can be life-threatening. Talk with your health care provider about these risks before taking this medicine.

What should I tell my health care provider before using felbamate?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if felbamate is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Liver or kidney problems
  • Mental health problems, such as depression, history of suicidal thoughts, or other mood problems

Other Medicines and Supplements. Felbamate may interact with other medicines and supplements. Before taking felbamate, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how felbamate could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will tell you if you should take felbamate while you are pregnant or trying to get pregnant. If you become pregnant while taking felbamate, you can sign up for the North American Antiepileptic Drug Pregnancy Registry by calling 888-233-2334 or at www.aedpregnancyregistry.org. This registry collects safety information about the use of seizure medicines during pregnancy.

Breastfeeding. Felbamate passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will tell you if you should take felbamate while breastfeeding.

Interactions

Does felbamate interact with foods or drinks?

There are no known interactions between felbamate and foods or drinks.

Do not drink alcohol while taking felbamate. The risk of liver damage, dizziness, and drowsiness may be increased if you drink alcohol while taking felbamate.

Does felbamate interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking felbamate.

  • Phenytoin (Dilantin, Phenytek, and others) or phenobarbital, which are medicines to control seizures 
  • Carbamazepine (Carbatrol, Tegretol, and others), which is a medicine commonly used to treat seizures or nerve pain
  • Divalproex sodium, valproate sodium, and valproic acid (Depakote and others), which are medicines used for seizures and other conditions
  • Any other medicine that causes dizziness and sleepiness, such as prescription pain medicines, sleep medicines, or medicines for anxiety

Some other medicines may alter the blood levels of felbamate, and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with felbamate. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much felbamate?

If you or someone else has used too much felbamate, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of felbamate?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.