Clobazam side effects: what 24,263 FDA adverse event reports show
Who reports
24,263 reports · 79% serious · 1,565 with death outcome · 52% female
Used for
Clobazam oral suspension is indicated for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients 2 years of age or older. Clobazam oral suspension is a benzodiazepine indicated for adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients 2 years of age or older ( 1 )
What it is
Table 4. Description Product Name: Clobazam oral suspension Established Name: Clobazam Oral Suspension Dosage Forms: Oral Suspension Route of Administration: Oral Established Pharmacologic Class of Drug: Benzodiazepine
Boxed warning
RISKS FROM CONCOMITANT USE WITH OPIOIDS; ABUSE, MISUSE, AND ADDICTION; and DEPENDENCE AND WITHDRAWAL REACTIONS Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs for patients for whom alternative treatment options are inadequate.
Causality screen of the 40 strongest signals
What the badges mean
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 1,097 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Automatism epileptic | 17 | 762.0 396.1–1,465.7ROR 762.5 · χ² 6,422 / p <1e-300 | 277.2 EB05 183.3 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=17 | not reported in cached trials |
| Epilepsy with myoclonic-atonic seizures | 12 | 638.7 302.2–1,349.9ROR 639.0 · χ² 4,009 / p <1e-300 | 231.3 EB05 141.0 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious n=12 | not reported in cached trials |
| Mitochondrial dna mutation | 34 | 567.7 367.9–876.1ROR 568.5 · χ² 11,203 / p <1e-300 | 286.2 EB05 214.2 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=34 · ♀ 100% (drug 52%) | not reported in cached trials |
| Severe myoclonic epilepsy of infancy | 11 | 493.0 234.7–1,035.9ROR 493.3 · χ² 3,116 / p <1e-300 | 203.0 EB05 121.0 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Epilepsia partialis continua | 15 | 473.1 251.7–889.3ROR 473.4 · χ² 4,244 / p <1e-300 | 219.6 EB05 141.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Anorectal malformation | 17 | 371.2 210.0–656.1ROR 371.5 · χ² 4,117 / p <1e-300 | 200.7 EB05 132.7 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=17 | not reported in cached trials |
| Brain lobectomy | 14 | 277.3 151.7–506.7ROR 277.4 · χ² 2,702 / p <1e-300 | 163.2 EB05 103.3 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Atonic seizures | 170 | 234.6 198.1–277.9ROR 236.3 · χ² 30,824 / p <1e-300 | 180.5 EB05 158.8 · IC025 +6.7 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=155 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| New onset refractory status epilepticus | 22 | 225.7 141.1–361.1ROR 225.9 · χ² 3,715 / p <1e-300 | 154.9 EB05 107.8 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=22 · 100% clinician | not reported in cached trials |
| Angiofibroma | 15 | 216.5 122.9–381.6ROR 216.6 · χ² 2,396 / p <1e-300 | 142.0 EB05 91.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Seizure cluster | 157 | 209.9 176.3–249.8ROR 211.3 · χ² 26,019 / p <1e-300 | 165.2 EB05 144.6 · IC025 +6.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=148 | not reported in cached trials |
| Victim of child abuse | 48 | 208.6 152.1–285.9ROR 209.0 · χ² 7,798 / p <1e-300 | 157.3 EB05 123.4 · IC025 +5.5 3/3 methods agree | Reporting / coding artifact | serious n=48 · ♀ 0% (drug 52%) | not reported in cached trials |
| Multiple-drug resistance | 586 | 202.2 185.0–221.1ROR 207.2 · χ² 94,662 / p <1e-300 | 162.7 EB05 152.0 · IC025 +7.0 3/3 methods agree | Reporting / coding artifact | serious n=474 · 92% clinician | not reported in cached trials |
| Child abuse | 45 | 189.7 137.4–262.0ROR 190.1 · χ² 6,755 / p <1e-300 | 145.8 EB05 113.5 · IC025 +5.4 3/3 methods agree | Reporting / coding artifact | serious n=45 · ♀ 0% (drug 52%) | not reported in cached trials |
| Csf oligoclonal band present | 22 | 189.2 119.3–300.3ROR 189.4 · χ² 3,218 / p <1e-300 | 136.9 EB05 95.3 · IC025 +4.4 3/3 methods agree | Lab value / disease marker | serious n=22 · ♀ 100% (drug 52%) · 100% clinician | not reported in cached trials |
| Asteatosis | 20 | 185.1 114.2–300.2ROR 185.3 · χ² 2,859 / p <1e-300 | 133.2 EB05 91.0 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=20 | not reported in cached trials |
| Vagal nerve stimulator implantation | 52 | 183.7 136.2–247.9ROR 184.1 · χ² 7,624 / p <1e-300 | 143.4 EB05 113.6 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=52 | NCT01160770: 4/267 (1.5%) on Clobazam (serious AE) |
| Change in seizure presentation | 114 | 181.8 148.6–222.5ROR 182.7 · χ² 16,744 / p <1e-300 | 146.4 EB05 125.2 · IC025 +6.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=107 | not reported in cached trials |
| Drug withdrawal convulsions | 309 | 181.1 160.3–204.6ROR 183.4 · χ² 45,495 / p <1e-300 | 148.2 EB05 134.8 · IC025 +6.7 3/3 methods agree | Not in label — unassessed | serious n=308 | not reported in cached trials |
| Epileptic encephalopathy | 38 | 179.8 126.7–255.0ROR 180.1 · χ² 5,432 / p <1e-300 | 138.4 EB05 105.3 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=38 · ♀ 17% (drug 52%) | not reported in cached trials |
| Coma blister | 15 | 170.3 97.9–296.5ROR 170.4 · χ² 1,965 / p <1e-300 | 120.7 EB05 77.6 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Haematuria traumatic | 11 | 167.3 87.7–319.2ROR 167.4 · χ² 1,384 / p <1e-300 | 113.1 EB05 67.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Epidural lipomatosis | 55 | 162.1 121.5–216.2ROR 162.4 · χ² 7,262 / p <1e-300 | 130.2 EB05 103.8 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=55 · ♀ 0% (drug 52%) · 91% clinician | not reported in cached trials |
| Developmental regression | 19 | 147.1 90.4–239.3ROR 147.2 · χ² 2,228 / p <1e-300 | 111.8 EB05 75.6 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=18 | not reported in cached trials |
| Lennox-gastaut syndrome | 32 | 143.4 98.6–208.5ROR 143.6 · χ² 3,752 / p <1e-300 | 114.6 EB05 85.0 · IC025 +4.8 3/3 methods agree | Likely indication confounding term in indications | serious n=32 · ♀ 29% (drug 52%) | NCT01160770: 5/267 (1.9%) on Clobazam (serious AE) |
| Postictal psychosis | 22 | 143.0 91.1–224.6ROR 143.1 · χ² 2,536 / p <1e-300 | 111.0 EB05 77.3 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=22 · 100% clinician | not reported in cached trials |
| Sudden unexplained death in epilepsy | 71 | 130.6 101.8–167.6ROR 131.0 · χ² 7,805 / p <1e-300 | 110.1 EB05 90.2 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious n=71 · ♀ 24% (drug 52%) · 94% clinician | not reported in cached trials |
| Lymphangioleiomyomatosis | 14 | 126.8 72.4–222.3ROR 126.9 · χ² 1,414 / p <1e-300 | 96.4 EB05 61.0 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Psychogenic seizure | 118 | 126.7 104.5–153.7ROR 127.3 · χ² 12,703 / p <1e-300 | 108.5 EB05 93.1 · IC025 +5.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=112 · ♀ 82% (drug 52%) · 100% clinician | not reported in cached trials |
| Tonic convulsion | 147 | 101.2 85.3–120.0ROR 101.8 · χ² 12,946 / p <1e-300 | 89.5 EB05 78.0 · IC025 +5.8 3/3 methods agree | Not in label — unassessed | serious n=144 | not reported in cached trials |
| Myoclonic epilepsy | 148 | 96.5 81.5–114.3ROR 97.1 · χ² 12,480 / p <1e-300 | 85.9 EB05 74.9 · IC025 +5.8 3/3 methods agree | Not in label — unassessed | serious n=143 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| Pneumonitis aspiration | 33 | 93.7 65.4–134.2ROR 93.8 · χ² 2,643 / p <1e-300 | 80.7 EB05 60.1 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=33 · ♀ 100% (drug 52%) · 100% clinician | not reported in cached trials |
| Anticonvulsant drug level increased | 142 | 82.6 69.6–98.1ROR 83.1 · χ² 10,361 / p <1e-300 | 74.7 EB05 64.9 · IC025 +5.6 3/3 methods agree | Lab value / disease marker | serious n=91 | not reported in cached trials |
| Neuroprosthesis implantation | 11 | 79.4 42.8–147.2ROR 79.4 · χ² 709 / p 2e-156 | 64.9 EB05 38.7 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Oropharyngeal oedema | 12 | 78.0 43.2–140.9ROR 78.0 · χ² 767 / p 5e-169 | 64.5 EB05 39.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Abdominal wall cyst | 10 | 77.4 40.5–147.9ROR 77.5 · χ² 623 / p 8e-138 | 62.9 EB05 36.5 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=10 | not reported in cached trials |
| Postictal paralysis | 19 | 73.5 46.0–117.5ROR 73.6 · χ² 1,186 / p 4e-260 | 63.6 EB05 43.1 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=19 | not reported in cached trials |
| Hip dysplasia | 17 | 71.3 43.5–117.0ROR 71.4 · χ² 1,024 / p 7e-225 | 61.6 EB05 40.7 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=17 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| Congenital aplasia | 22 | 71.0 45.9–109.6ROR 71.0 · χ² 1,337 / p 5e-293 | 62.2 EB05 43.3 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=22 | not reported in cached trials |
| Propofol infusion syndrome | 47 | 61.6 45.8–82.8ROR 61.7 · χ² 2,556 / p <1e-300 | 56.2 EB05 44.0 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=47 · ♀ 100% (drug 52%) | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Clobazam as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (5 of 40 signal terms matched).
- NCT01160770 — Safety and Effectiveness of Open-Label Clobazam in Subjects With Lennox-Gastaut Syndrome (N=267, PHASE3; 191 AE terms posted; arms: Clobazam)
- NCT00518713 — Clobazam in Patients With Lennox-Gastaut Syndrome (N=238, PHASE3; 53 AE terms posted; arms: Clobazam Low Dose; Clobazam Medium Dose; Clobazam High Dose; Placebo)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Seizure | 4,947 | 38.9 37.9–39.9ROR 48.6 · χ² 175,604 / p <1e-300 | 37.2 EB05 36.4 · IC025 +5.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 25.8 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| Drug ineffective (drug did not work) | 3,150 | 2.1 2.0–2.1ROR 2.2 · χ² 1,852 / p <1e-300 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Reporting / coding artifact | serious PRR 3.7 | not reported in cached trials |
| Off label use (used outside approved label) | 2,248 | 2.2 2.2–2.3ROR 2.4 · χ² 1,607 / p <1e-300 | 2.2 EB05 2.2 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious PRR 2.6 | not reported in cached trials |
| Somnolence (drowsiness) | 1,944 | 8.4 8.1–8.8ROR 9.1 · χ² 12,715 / p <1e-300 | 8.3 EB05 8.0 · IC025 +3.0 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 7.2 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| Drug interaction | 1,170 | 6.4 6.1–6.8ROR 6.7 · χ² 5,339 / p <1e-300 | 6.4 EB05 6.1 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious PRR 4.3 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| Fatigue (tiredness) | 1,150 | 1.3 1.2–1.4ROR 1.3 · χ² 72 / p 8e-18 | 1.3 EB05 1.2 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.1 | NCT01160770: 18/267 (6.7%) on Clobazam |
| Epilepsy | 851 | 24.8 23.2–26.5ROR 25.6 · χ² 18,862 / p <1e-300 | 24.1 EB05 22.8 · IC025 +4.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 17.6 | NCT01160770: 2/267 (0.7%) on Clobazam (serious AE) |
| Condition aggravated | 841 | 2.4 2.3–2.6ROR 2.5 · χ² 701 / p 1e-154 | 2.4 EB05 2.3 · IC025 +1.2 3/3 methods agree | Reporting / coding artifact | serious PRR 2.1 | not reported in cached trials |
| Status epilepticus | 725 | 59.1 54.9–63.7ROR 60.9 · χ² 38,703 / p <1e-300 | 55.3 EB05 52.0 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious PRR 40.5 | NCT01160770: 11/267 (4.1%) on Clobazam (serious AE) |
| Pneumonia (lung infection) | 705 | 1.9 1.8–2.0ROR 1.9 · χ² 297 / p 9e-67 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.4 | NCT01160770: 2/267 (0.7%) on Clobazam (serious AE) |
| Product use in unapproved indication | 704 | 2.5 2.3–2.7ROR 2.5 · χ² 634 / p 3e-140 | 2.5 EB05 2.3 · IC025 +1.2 3/3 methods agree | Reporting / coding artifact | serious PRR 2.7 | not reported in cached trials |
| Generalised tonic-clonic seizure | 682 | 37.6 34.8–40.5ROR 38.6 · χ² 23,222 / p <1e-300 | 36.0 EB05 33.8 · IC025 +5.0 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 25.4 | not reported in cached trials |
| Fall | 666 | 1.7 1.6–1.9ROR 1.8 · χ² 208 / p 2e-47 | 1.7 EB05 1.6 · IC025 +0.7 | Not in label — unassessed | serious PRR 1.4 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
| Decreased appetite (loss of appetite) | 652 | 2.4 2.3–2.6ROR 2.5 · χ² 555 / p 5e-123 | 2.4 EB05 2.3 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.1 | NCT01160770: 14/267 (5.2%) on Clobazam |
| Aggression | 641 | 11.2 10.3–12.1ROR 11.4 · χ² 5,864 / p <1e-300 | 11.0 EB05 10.3 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.3 | NCT01160770: 1/267 (0.4%) on Clobazam (serious AE) |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Mitochondrial dna mutation — n=34, PRR 567.7
- New onset refractory status epilepticus — n=22, PRR 225.7
- Asteatosis — n=20, PRR 185.1
- Vagal nerve stimulator implantation — n=52, PRR 183.7 (also seen in trial arm)
- Drug withdrawal convulsions — n=309, PRR 181.1
- Epileptic encephalopathy — n=38, PRR 179.8
- Epidural lipomatosis — n=55, PRR 162.1
- Postictal psychosis — n=22, PRR 143.0
- Sudden unexplained death in epilepsy — n=71, PRR 130.6
- Tonic convulsion — n=147, PRR 101.2
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Clobazam?
In FDA FAERS, the most frequently co-reported reaction terms for Clobazam are seizure, somnolence, fatigue, epilepsy, status epilepticus, pneumonia. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Clobazam have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: RISKS FROM CONCOMITANT USE WITH OPIOIDS; ABUSE, MISUSE, AND ADDICTION; and DEPENDENCE AND WITHDRAWAL REACTIONS Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs for patients for whom alternative treatment options are inadequate.
Do FAERS signals prove that Clobazam causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 07e0ae51-cc71-427f-83cb-311b7fcc5993, effective 20260709; matched on
openfda.generic_name.exact:"CLOBAZAM") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 1,137 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath - ClinicalTrials.gov API v2 (query
CLOBAZAM, results-bearing studies sorted by enrollment)
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.