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Clobazam Side Effects

For the Consumer

Applies to clobazam: oral suspension, oral tablet

Along with its needed effects, clobazam may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking clobazam:

More common
  • Difficulty with swallowing
  • fever
  • shakiness and unsteady walk
  • unsteadiness, trembling, or other problems with muscle control or coordination
Less common
  • Change in speech pattern
  • restlessness
  • slurred speech
  • trouble sitting still
  • trouble speaking
Incidence not known
  • Agitation
  • black, tarry stools
  • bleeding gums
  • blistering, peeling, or loosening of the skin
  • blood in the urine or stools
  • chest pain
  • chills
  • confusion as to time, place, or person
  • cough
  • diarrhea
  • difficult or troubled breathing
  • holding false beliefs that cannot be changed by fact
  • irregular, fast or slow, or shallow breathing
  • itching
  • joint or muscle pain
  • lack of feeling or emotion
  • painful or difficult urination
  • pale or blue lips, fingernails, or skin
  • pinpoint red spots on the skin
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • seeing, hearing, or feeling things that are not there
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • swollen glands
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual excitement, nervousness, or restlessness
  • unusual tiredness or weakness

Some side effects of clobazam may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Aggressive
  • body aches or pain
  • decreased appetite
  • difficulty having a bowel movement (stool)
  • drooling
  • ear congestion
  • irritability
  • loss of voice
  • nasal congestion
  • runny nose
  • sleepiness or unusual drowsiness
  • sneezing
  • vomiting
Less common
  • Bladder pain
  • cloudy urine
  • cough with mucus
  • frequent urge to urinate
  • increased appetite
  • lower back or side pain
Incidence not known
  • Double vision
  • full or bloated feeling
  • headache
  • muscle spasms
  • pressure in the stomach
  • rash, hives, or welts
  • red skin
  • swelling of the stomach area

For Healthcare Professionals

Applies to clobazam: oral suspension, oral tablet


The most commonly reported side effects were somnolence, lethargy, drooling, and ataxia.[Ref]


Very common (10% or more): Aggression (up to 14%)
Common (1% to 10%): Insomnia, irritability, depression
Uncommon (0.1% to 1%): Decreased libido or loss of libido, euphoria, numbed emotions, preexisting depression may be unmasked during benzodiazepine use
Frequency not reported: Withdrawal symptoms, physical and psychological dependence, suicidal behavior and ideation
Postmarketing reports: Agitation, anxiety, apathy, confusional state, delirium, delusion, hallucination[Ref]

Nervous system

Very common (10% or more): Somnolence ( up to 32%), lethargy (up to 15%), drooling ( up to 14%), ataxia (up to 10%)
Common (1% to 10%): Sedation, psychomotor hyperactivity, dysarthria, dizziness, headache, confusion, slurred speech, tremor
Uncommon (0.1% to 1%): Anterograde amnesia, amnesia
Frequency not reported: Potentiation of sedation from concomitant use with central nervous system depressants[Ref]


Common (1% to 10%): Rash
Uncommon (0.1% to 1%): Sweating
Postmarketing reports: Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), urticaria, angioedema, facial and lip edema[Ref]


Postmarketing reports: Increased hepatic enzyme[Ref]


Very common (10% or more): Upper respiratory tract infection (up to 14%)
Common (1% to 10%): Pneumonia, bronchitis, cough
Uncommon (0.1% to 1%): Respiratory depression
Postmarketing reports: Aspiration, respiratory depression[Ref]


Common (1% to 10%): Hypotension[Ref]


Very common (10% or more): Constipation (10%)
Common (1% to 10%): Vomiting, dysphagia, dry mouth, diarrhea, nausea
Postmarketing reports: Abdominal distention[Ref]


Common (1% to 10%): Urinary tract infection
Postmarketing reports: Urinary retention[Ref]


Common (1% to 10%): Increased appetite, decreased appetite
Uncommon (0.1% to 1%): Anorexia[Ref]


Uncommon (0.1% to 1%): Muscle aches, weakness, stiffness, spasm[Ref]


Frequency not reported: Nystagmus
Postmarketing reports: Diplopia, vision blurred[Ref]


Very common (10% or more): Pyrexia ( up to 17%), irritability (up to 11%)
Common (1% to 10%): Fatigue
Uncommon (0.1% to 1%): Hangover
Postmarketing reports: Hypothermia[Ref]


Postmarketing reports: Anemia, eosinophilia, leukopenia, thrombocytopenia[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Onfi (clobazam)." Lundbeck Inc, Deerfield, IL.

Some side effects of clobazam may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.