What You Need to Know About Onfi (Clobazam)

This anticonvulsant is used for epilepsy and other conditions

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Clobazam, also sold under the brand name Onfi, is an older anti-seizure (anticonvulsant) medication. It a prescription drug in the benzodiazepine class that is known to be less sedating than others because its chemical structure differs slightly, according to a review on the medication in the journal Pediatric Reports. Additionally, the drug may be better tolerated than other anti-seizure medications, particularly when used with other epilepsy drugs.

Clobazam is often used in conjunction with other anti-seizure medications to control seizures in adults and children over 2 years of age.

Uses

Most notably, clobazam is used in Lennox-Gastaut syndrome, a serious form of epilepsy that can present with several types of seizures plus intellectual and developmental disabilities. The drug works by reducing the brain’s atypical electrical activity that can lead to seizures.

Furthermore, benzodiazepines have often been used to treat anxiety, and there may be some instances where clobazam is prescribed for this condition. In December 2017, the Kennedy Krieger Institute in Baltimore, Md. announced a clinical trial to explore the use of clobazam in pediatric patients who have a diagnosis of epilepsy and “clinically significant” anxiety that impairs daily life to assess whether it improves outcomes for both conditions. The trial is still ongoing.

Besides seizures and anxiety, there may be others uses and conditions for which the doctor prescribes you this medication.

Formulation and Dosing

Clobazam comes in a 10 milligram (mg) and 20 mg tablet, as well as a 2.5 mg liquid. The dose of the medication differs from one person to the next.

Your doctor will likely start you on a low dose of the medication and work up to a higher dose, with an increase every couple of weeks. Although your doctor will provide you with instructions as to how to take the medication, the following are some general recommendations:

  • Clobazam is usually taken once or twice a day, and it can be taken with or without food.
  • Stick to a schedule and try to take it at the same time each day.
  • If you have trouble swallowing the pills, you can crush them up and place them in applesauce.
  • Don’t take more or less of the prescribed amount of the medication.
  • If you miss a dose, take the next dose as soon as you can. If it’s close to the time you take your next dose, skip the missed dose and resume your medication as prescribed.

If you’re taking clobazam in liquid form, you may have particular guidelines to follow, such as shaking the bottle to mix the drug before use, using the adapter and syringe to measure out the correct amount of medication, storing the medication at room temperature, or other specific instructions.  

To ensure that the medication is achieving the desired outcome, your health care provider will want to schedule regular checkups to monitor your progress.

Never stop taking clobazam without first speaking with your doctor.

Side Effects

You may experience some unwanted side effects when taking clobazam, which can range from mild to severe. Although one person’s experience with the medication will likely be different than another’s, the following are some mild side effects that can be associated with the drug, according to the National Institutes of Health (NIH):

  • Fatigue
  • Impaired coordination
  • New onset of difficulty speaking or swallowing
  • Drooling
  • Pain in the muscles or joints
  • Nausea and vomiting
  • Reduction in appetite
  • Changes in bowel habits, such as constipation
  • A cough that coincides with the start of the medication

With some of these in mind, make sure you understand how your body reacts to the medication before driving or operating machinery to keep you and others around you safe.

Note that alcohol compounds the clobazam's effects on the central nervous system (CNS) and may increase feelings of drowsiness, fatigue, and decreased alertness.

Serious Side Effects

The following can also occur and warrant emergency care:

  • Changes in urination, such as bladder pain, difficulty voiding, and increased urinary frequency
  • Trouble breathing
  • Rashes, such as hives, or peeling or blistering of the skin
  • Fever or elevated temperature
  • Sores in the mouth

The dermatological and oral symptoms may be due to potentially life-threatening reactions like Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), which can be caused by clobazam. Both conditions may also include flu-like symptoms, such as fever and body aches.

Precautions and Contraindications

If you’ve had an allergic reaction to clobazam in the past, are allergic to the ingredients that make up the drug, or have had reactions to other benzodiazepine medications, you may not be a good candidate for this medication. Talk to your doctor about alternatives.

Be sure to let your doctor know if you’re taking other prescription medications (including birth control), over-the-counter-drugs, vitamins, supplements, and herbs. These may interfere with the drug's effectiveness, so your doctor may need to adjust your dose accordingly and monitor you for the presence of side effects.

Let your doctor know if you are pregnant, breastfeeding, or planning to get pregnant. At this time, there’s a lack of well-controlled studies on clobazam and its impact on pregnant women. The drug is listed as being in pregnancy category C, which indicates the drug should be used with caution providing the benefits of using it outweigh the risks.

If you have any questions regarding clobazam and pregnancy, talk with your doctor. Our Doctor Discussion Guide below can help you start that conversation.

Epilepsy Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

A Word From Verywell

Anytime you begin a new medication, it’s natural to have questions and concerns. If you’re uncertain about taking clobazam, be sure to ask your doctor or pharmacist to clarify anything you don’t understand. Also, if you experience lingering side effects that don’t go away or interfere with your life, be sure to consult with your doctor as soon as possible so that you and your health care provider can discuss which treatment options may be right for you.

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