[Posted 12/03/2013]ISSUE: FDA is warning the public that the anti-seizure drug Onfi (clobazam) can cause rare but serious skin reactions that can result in permanent harm and death. FDA approved changes to the Onfi drug label and the patient Medication Guide to describe the risk of these serious skin reactions.
These skin reactions, called Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), can occur at any time during Onfi treatment. However, the likelihood of skin reactions is greater during the first 8 weeks of treatment or when Onfi is stopped and then re-started. All cases of SJS and TEN in the FDA case series have resulted in hospitalization, one case resulted in blindness, and one case resulted in death. See the FDA Drug Safety Communication for a Data Summary and additional information.
The Onfi drug label has been revised to add information about the risk for serious skin reactions to the Warnings and Precautions section and to the Medication Guide.
BACKGROUND: Onfi is a benzodiazepine medication used in combination with other medicines to treat seizures associated with a severe form of epilepsy called Lennox-Gastaut Syndrome.
RECOMMENDATION: Patients should be closely monitored for signs or symptoms of SJS/TEN, especially during the first 8 weeks of treatment or when re-introducing therapy. Health care professionals should discontinue use of Onfi and consider an alternate therapy at the first sign of rash, unless it is clearly not drug-related
Patients taking Onfi should seek immediate medical treatment if they develop a rash, blistering or peeling of the skin, sores in the mouth, or hives. Patients should not stop taking Onfi without first talking to their health care professionals. Stopping Onfi suddenly can cause serious withdrawal problems, such as seizures that will not stop, hallucinations, shaking, nervousness, and stomach or muscle cramps.
For more information visit the FDA website at: Web Siteand Web Site.
Clobazam is used with other medication(s) to control seizures in adults and children 2 years of age and older who have Lennox-Gastaut syndrome (a disorder that causes seizures and often causes developmental delays). Clobazam is in a class of medications called benzodiazepines. It works by decreasing abnormal electrical activity in the brain.
Clobazam comes as a tablet to take by mouth. It is usually taken once or twice a day, with or without food. Take clobazam at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.
If you are unable to swallow the tablets whole, you may crush them and mix with a small amount of applesauce.
Your doctor will probably start you on a low dose of clobazam and gradually increase your dose, not more than once every week.
Some people may respond differently to clobazam based on their heredity or genetic makeup. Your doctor may order a blood test to help find the dose of clobazam that is best for you.
Clobazam can be habit forming. Take clobazam exactly as directed. Do not take a larger dose, take it more often, or take it for a longer period of time than prescribed by your doctor.
Clobazam may help control your condition but will not cure it. Continue to take clobazam even if you feel well. Do not stop taking clobazam without talking to your doctor. If you suddenly stop taking clobazam, you may experience withdrawal symptoms such as new or worsening seizures, hallucinating (seeing things or hearing voices that do not exist), behavior changes, depressed mood, loss of contact with reality, restlessness, irritability, panic attacks, difficulty concentrating, anxiety, difficulty falling asleep or staying asleep, headache, blurred vision, eye sensitivity to light, uncontrollable shaking of a part of your body, fast heartbeat, sweating, muscle pain and stiffness, stomach or muscle cramps, nausea, diarrhea, or weight loss. Your doctor will probably decrease your dose gradually.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with clobazam and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website ( Web Site) or the manufacturer's website to obtain the Medication Guide.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking clobazam,
- tell your doctor and pharmacist if you are allergic to clobazam, any other medications, or any of the ingredients in clobazam tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antidepressants; fluconazole (Diflucan); fluvoxamine (Luvox); hormonal contraceptives (birth control pills, patches, rings, implants, injections, or intrauterine devices); medications for anxiety, mental illness, pain, or seizures; omeprazole (Prilosec, Zegerid); sedatives; sleeping pills; ticlopidine (Ticlid); or tranquilizers. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with clobazam, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
- tell your doctor if you drink or have ever drunk large amounts of alcohol or use or have ever used street drugs or excessive amounts of prescription medications. Also tell your doctor if you have or have ever had depression, mood problems, or thoughts about harming or killing yourself, or planning or trying to do so; or lung, kidney, or liver disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you are using hormonal contraceptives, you should know that this type of birth control may not work well when used with clobazam. Hormonal contraceptives should not be used as your only method of birth control while you are taking clobazam and for 28 days after you stop taking it. Talk to your doctor about birth control methods that will work for you. If you become pregnant while taking clobazam, call your doctor.
- talk to your doctor about the risks and benefits of taking this medication if you are 65 years of age or older. Older adults should receive low doses of clobazam because higher doses may not work better and may cause serious side effects.
- you should know that clobazam may make you drowsy and affect your thinking, ability to make decisions, and coordination. Do not drive a car, operate machinery, or do other dangerous activities until you know how this medication affects you.
- ask your doctor about the safe use of alcoholic beverages while you are taking clobazam. Alcohol can make the side effects from clobazam worse.
- you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking clobazam. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants, such as clobazam, to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as one week after they started taking the medication. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); thinking about harming or killing yourself, or planning or trying to do so; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.
Unless your doctor tells you otherwise, continue your normal diet.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Clobazam may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- problems with coordination
- difficulty speaking or swallowing
- change in appetite
Some side effects can be serious. If you experience any of these symptoms or those listed in the SPECIAL PRECAUTIONS section, call your doctor immediately or get emergency medical treatment:
- difficult, painful, or frequent urination
- difficulty breathing
- peeling or blistering skin
Clobazam may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store clobazam in a safe place so that no one else can take it accidentally or on purpose. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include the following:
- lack of energy
- problems with coordination
- slow, shallow breathing
- decreased urge to breathe
- blurred vision
Keep all appointments with your doctor.
Do not let anyone else take your medication. Clobazam is a controlled substance. Prescriptions may be refilled only a limited number of times; ask your pharmacist if you have any questions.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Selected Revisions: December 15, 2013.