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What is clobazam?

Clobazam (also called Onfi®) is used to treat certain types of seizures. It may be given for other reasons. Talk with your doctor. Clobazam is available as a 10 mg and 20 mg tablet or a liquid suspension that is taken by mouth.

Possible side effects of clobazam

Most common

  • Clumsiness, trouble with coordination, weakness
  • Hard stools (constipation)
  • Feeling dizzy, drowsy, or sleepy
  • Drooling
  • Fever
  • Vomiting (throwing up)
  • Cough

If you have any of these side effects, tell the doctor right away:       

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Short of breath
  • Fever
  • Change in balance
  • Feeling confused
  • Seizures that are different, worse, or occur more often after starting this medicine
  • Feeling very tired or weak
  • Pain when passing urine
  • Slurred speech
  • Not able to sleep
  • Feeling very dizzy or passing out
  • Feeling very sleepy
  • Blistering, peeling, or red skin rash
  • Feeling confused or unusually excited, nervous, or irritable
  • Feeling depressed or anxious or having thoughts of hurting yourself or others
  • Seeing things that are not there (hallucinating)

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse, or pharmacist at 901-595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833).

How to take clobazam

Clobazam may be taken with or without food. Take with food if it causes an upset stomach.

Oral tablet:

  • Tablet may be crushed and mixed with applesauce.
  • Take the mixed drug right away. Do not store for use at a later time.

Oral liquid suspension:

  • Shake well before use.
  • Use an oral syringe to measure the dose of this liquid medicine.

Special instructions for clobazam

  • Tell all of your health care providers that you are taking this medicine. This includes doctors, nurses, pharmacists, and dentists.
  • Tell your doctor right away if you become pregnant or are breast-feeding a baby.
  • Some medicines can affect how clobazam works. Tell your doctor if you are also using any of the following:
    • Birth control pills and other hormone-based birth control might not work as well to prevent pregnancy. Use an extra form of birth control, like a condom, when taking this medicine. Continue for 28 days after the medicine is stopped.
    • Fluconazole
    • Fluvoxamine
    • Omeprazole (Prilosec®)
    • Ticlopidine
  • Birth control pills
  • This medicine may be habit-forming with long-term use.
  • Do not change the dose or stop taking without first talking to your doctor. This could cause seizures. If you need to stop this medicine, you will want to slowly stop it as ordered by the doctor.
  • Avoid tasks or actions that require you to be alert until you see how this medicine affects you.
  • Talk with the doctor before taking other medicines, over-the-counter drugs, and herbal products that may slow your actions.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).