Prescription Drug Information: Clobazam (Page 2 of 7)

5.4 Potentiation of Sedation from Concomitant Use with Central Nervous System Depressants

Since clobazam has a central nervous system (CNS) depressant effect, patients or their caregivers should be cautioned against simultaneous use with other CNS depressant drugs or alcohol, and cautioned that the effects of other CNS depressant drugs or alcohol may be potentiated [see Drug Interactions (7.2)].

5.5 Somnolence or Sedation

Clobazam causes somnolence and sedation. In clinical trials, somnolence or sedation was reported at all effective doses and was dose-related.

In general, somnolence and sedation begin within the first month of treatment and may diminish with continued treatment. Prescribers should monitor patients for somnolence and sedation, particularly with concomitant use of other central nervous system depressants. Prescribers should caution patients against engaging in hazardous activities requiring mental alertness, such as operating dangerous machinery or motor vehicles, until the effect of clobazam is known.

5.6 Serious Dermatological Reactions

Serious skin reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have been reported with clobazam in both children and adults during the postmarketing period. Patients should be closely monitored for signs or symptoms of SJS/TEN, especially during the first 8 weeks of treatment initiation or when re-introducing therapy. Clobazam should be discontinued at the first sign of rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed and alternative therapy should be considered [see Contraindications (4)].

5.7 Suicidal Behavior and Ideation

Antiepileptic drugs (AEDs), including clobazam, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.

Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted relative risk 1.8, 95% confidence interval [CI]: 1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.

The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.

The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5 to 100 years) in the clinical trials analyzed. Table 2 shows absolute and relative risk by indication for all evaluated AEDs.

Table 2. Risk by Indication for Antiepileptic Drugs in the Pooled Analysis
Indication Placebo Patients with Events per 1000 Patients Drug Patients with Events per 1000 Patients Relative Risk: Incidence of Drug Events in Drug Patients/Incidence in Placebo Patients Risk Difference: Additional Drug Patients with Events per 1000 Patients
Epilepsy 1.0 3.4 3.5 2.4
Psychiatric 5.7 8.5 1.5 2.9
Other 1.0 1.8 1.9 0.9
Total 2.4 4.3 1.8 1.9

The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.

Anyone considering prescribing clobazam tablets or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.

Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.


Clinically significant adverse reactions that appear in other sections of the labeling include the following:

  • Risks from Concomitant Use with Opioids [see Warnings and Precautions (5.1)]
  • Abuse, Misuse, and Addiction [see Warnings and Precautions (5.2)]
  • Dependence and Withdrawal Reactions [see Warnings and Precautions ( 5.3)]
  • Potentiation of Sedation from Concomitant Use with Central Nervous System Depressants [see Warnings and Precautions (5.4)]
  • Somnolence or Sedation [see Warnings and Precautions (5.5)]
  • Serious Dermatological Reactions [see Contraindications (4), Warnings and Precautions (5.6)]
  • Suicidal Behavior and Ideation [see Warnings and Precautions (5.7)]

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

During its development for the adjunctive treatment of seizures associated with LGS, clobazam was administered to 333 healthy volunteers and 300 patients with a current or prior diagnosis of LGS, including 197 patients treated for 12 months or more. The conditions and duration of exposure varied greatly and included single- and multiple-dose clinical pharmacology studies in healthy volunteers and two double-blind studies in patients with LGS (Study 1 and 2) [see Clinical Studies (14)]. Only Study 1 included a placebo group, allowing comparison of adverse reaction rates on clobazam at several doses to placebo.

Adverse Reactions Leading to Discontinuation in an LGS Placebo Controlled Clinical Trial (Study 1)

The adverse reactions associated with clobazam treatment discontinuation in ≥1% of patients in decreasing order of frequency included lethargy, somnolence, ataxia, aggression, fatigue, and insomnia.

Most Common Adverse Reactions in an LGS Placebo Controlled Clinical Trial (Study 1)

Table 3 lists the adverse reactions that occurred in ≥5% of clobazam-treated patients (at any dose), and at a rate greater than placebo-treated patients, in the randomized, double- blind, placebo-controlled, parallel group clinical study of adjunctive AED therapy for 15 weeks (Study 1).

Table 3. Adverse Reactions Reported for ≥5% of Patients and More Frequently than Placebo in Any Treatment Group

a Maximum daily dose of 5 mg for ≤30 kg body weight; 10 mg for >30 kg body weight

b Maximum daily dose of 10 mg for ≤30 kg body weight; 20 mg for >30 kg body weight

c Maximum daily dose of 20 mg for ≤30 kg body weight; 40 mg for >30 kg body weight

Clobazam Dose Level
Placebo N=59 % Lowa N=58 % Mediumb N=62 % Highc N=59 % All Clobazam N=179 %
Gastrointestinal Disorders
Vomiting 5 9 5 7 7
Constipation 0 2 2 10 5
Dysphagia 0 0 0 5 2
General Disorders and Administration Site Conditions
Pyrexia 3 17 10 12 13
Irritability 5 3 11 5 7
Fatigue 2 5 5 3 5
Infections and Infestations
Upper respiratory tract infection 10 10 13 14 12
Pneumonia 2 3 3 7 4
Urinary tract infection 0 2 5 5 4
Bronchitis 0 2 0 5 2
Metabolism and Nutrition Disorders
Decreased appetite 3 3 0 7 3
Increased appetite 0 2 3 5 3
Nervous System Disorders
Somnolence or Sedation 15 17 27 32 26
Somnolence 12 16 24 25 22
Sedation 3 2 3 9 5
Lethargy 5 10 5 15 10
Drooling 3 0 13 14 9
Ataxia 3 3 2 10 5
Psychomotor hyperactivity 3 3 3 5 4
Dysarthria 0 2 2 5 3
Psychiatric Disorders
Aggression 5 3 8 14 8
Insomnia 2 2 5 7 5
Respiratory Disorders
Cough 0 3 5 7 5 provides trustworthy package insert and label information about marketed prescription drugs as submitted by manufacturers to the U.S. Food and Drug Administration. Package information is not reviewed or updated separately by Every individual prescription drug label and package insert entry contains a unique identifier which can be used to secure further details directly from the U.S. National Institutes of Health and/or the FDA.

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