Drug · FAERS side-effect profile with label screen
Ethosuximide side effects: what 2,488 FDA adverse event reports show
Who reports
2,488 reports · 81% serious · 63 with death outcome · 58% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Ethosuximide capsule is indicated for the control of absence (petit mal) epilepsy.
FDA label, Indications and Usage
What it is
DESCRIPTION Ethosuximide, USP is an anticonvulsant succinimide, chemically designated as alpha-ethyl-alpha-methyl-succinimide, with the following structural formula: Each Ethosuximide Capsule,.
FDA label, Description section
Boxed warning
None in the current label
How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation.
Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)?
That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.
Causality screen of the 40 strongest signals
Labeled adverse reaction 7Labeled (related wording) 4Likely indication confounding 1Reporting / coding artifact 5Lab value / disease marker 1Not in label — unassessed 22
What the badges mean
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- 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. 65 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Generalised tonic-clonic seizure | 149 | 77.4 66.2–90.5ROR 82.3 · χ² 11,068 / p <1e-300 | 76.0 EB05 66.3 · IC025 +5.7 3/3 methods agree | Not in label — unassessed | serious PRR 53.0 | no trial data cached |
| Status epilepticus | 102 | 76.6 63.3–92.7ROR 79.9 · χ² 7,472 / p <1e-300 | 74.9 EB05 63.5 · IC025 +5.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 54.4 · 100% clinician | no trial data cached |
| Ataxia | 80 | 56.9 45.9–70.7ROR 58.8 · χ² 4,313 / p <1e-300 | 55.8 EB05 46.3 · IC025 +5.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 42.7 · ♀ 36% (drug 58%) · 97% clinician | no trial data cached |
| Epilepsy | 108 | 29.9 24.9–36.0ROR 31.2 · χ² 2,983 / p <1e-300 | 29.7 EB05 25.3 · IC025 +4.4 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 21.0 | no trial data cached |
| Seizure | 367 | 27.0 24.6–29.7ROR 31.5 · χ² 9,192 / p <1e-300 | 26.9 EB05 24.7 · IC025 +4.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 19.2 | no trial data cached |
| Myoclonus | 34 | 24.1 17.2–33.7ROR 24.4 · χ² 728 / p 1e-160 | 23.7 EB05 17.8 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious PRR 18.2 · 100% clinician | no trial data cached |
| Grand mal convulsion | 22 | 19.8 13.1–30.1ROR 20.0 · χ² 374 / p 1e-83 | 19.4 EB05 13.4 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 14.4 | no trial data cached |
| Drug resistance | 46 | 15.1 11.3–20.1ROR 15.4 · χ² 592 / p 5e-131 | 14.9 EB05 11.5 · IC025 +3.2 3/3 methods agree | Reporting / coding artifact | serious PRR 11.9 · 98% clinician | no trial data cached |
| Hypotonia | 16 | 13.5 8.3–21.9ROR 13.5 · χ² 172 / p 1e-39 | 12.5 EB05 7.5 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 11.0 | no trial data cached |
| Aggression | 79 | 13.3 10.7–16.5ROR 13.7 · χ² 886 / p 5e-195 | 13.1 EB05 10.8 · IC025 +3.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.7 | no trial data cached |
| Treatment failure | 116 | 11.9 10.0–14.2ROR 12.5 · χ² 1,153 / p 6e-253 | 11.8 EB05 10.1 · IC025 +3.2 3/3 methods agree | Reporting / coding artifact | serious PRR 15.8 · 96% clinician | no trial data cached |
| Encephalopathy | 34 | 11.7 8.4–16.4ROR 11.9 · χ² 322 / p 2e-72 | 11.2 EB05 8.2 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 · ♀ 7% (drug 58%) · 100% clinician | no trial data cached |
| Toxic epidermal necrolysis (severe skin peeling reaction) | 20 | 11.2 7.2–17.3ROR 11.3 · χ² 175 / p 3e-40 | 10.2 EB05 6.6 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 8.0 | no trial data cached |
| Convulsion (seizure) | 74 | 10.8 8.6–13.5ROR 11.1 · χ² 646 / p 7e-143 | 10.5 EB05 8.6 · IC025 +2.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.6 | no trial data cached |
| Poor quality product administered | 13 | 10.7 6.2–18.5ROR 10.8 · χ² 105 / p 6e-25 | 9.1 EB05 5.2 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=6 | no trial data cached |
| Psychotic disorder | 36 | 10.3 7.4–14.2ROR 10.4 · χ² 292 / p 8e-66 | 9.7 EB05 7.2 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 8.0 · 92% clinician | no trial data cached |
| Motor dysfunction | 12 | 10.0 5.7–17.6ROR 10.0 · χ² 88 / p 3e-21 | 8.3 EB05 4.7 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 9.0 | no trial data cached |
| Altered state of consciousness | 25 | 9.8 6.6–14.5ROR 9.9 · χ² 188 / p 4e-43 | 8.9 EB05 6.2 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 · ♀ 36% (drug 58%) · 100% clinician | no trial data cached |
| Psychomotor hyperactivity | 19 | 9.6 6.1–15.0ROR 9.7 · χ² 138 / p 4e-32 | 8.5 EB05 5.5 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 9.6 | no trial data cached |
| Thinking abnormal | 21 | 9.5 6.2–14.5ROR 9.5 · χ² 150 / p 7e-35 | 8.4 EB05 5.6 · IC025 +2.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 9.6 | no trial data cached |
| Cognitive disorder | 52 | 9.4 7.2–12.3ROR 9.6 · χ² 384 / p 1e-85 | 9.0 EB05 7.1 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 · 96% clinician | no trial data cached |
| Product taste abnormal | 15 | 9.4 5.7–15.6ROR 9.5 · χ² 104 / p 8e-25 | 8.0 EB05 4.9 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious n=2 | no trial data cached |
| Petechiae | 10 | 8.1 4.4–15.0ROR 8.1 · χ² 55 / p 5e-14 | 6.3 EB05 3.5 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 7.0 | no trial data cached |
| Joint dislocation | 10 | 8.0 4.3–14.9ROR 8.0 · χ² 54 / p 8e-14 | 6.2 EB05 3.5 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 6.4 | no trial data cached |
| Abnormal behaviour | 37 | 7.8 5.7–10.8ROR 7.9 · χ² 214 / p 1e-48 | 7.3 EB05 5.5 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 | no trial data cached |
| Increased appetite | 17 | 7.6 4.7–12.2ROR 7.7 · χ² 91 / p 6e-22 | 6.5 EB05 4.2 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 12.5 | no trial data cached |
| Myocarditis | 10 | 7.4 4.0–13.8ROR 7.5 · χ² 50 / p 1e-12 | 5.8 EB05 3.3 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.3 | no trial data cached |
| Depressed level of consciousness | 33 | 7.0 5.0–9.9ROR 7.1 · χ² 165 / p 4e-38 | 6.5 EB05 4.8 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 · ♀ 31% (drug 58%) · 93% clinician | no trial data cached |
| Therapy partial responder | 12 | 6.7 3.8–11.8ROR 6.7 · χ² 53 / p 2e-13 | 5.5 EB05 3.3 · IC025 +1.5 3/3 methods agree | Reporting / coding artifact | serious PRR 4.8 | no trial data cached |
| Somnolence (drowsiness) | 157 | 6.6 5.7–7.7ROR 7.0 · χ² 744 / p 3e-164 | 6.5 EB05 5.7 · IC025 +2.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.6 · ♀ 34% (drug 58%) | no trial data cached |
| Stevens-johnson syndrome (severe blistering skin reaction) | 17 | 6.4 4.0–10.3ROR 6.5 · χ² 73 / p 8e-18 | 5.6 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.6 | no trial data cached |
| Drug interaction | 116 | 6.2 5.2–7.4ROR 6.4 · χ² 500 / p 5e-111 | 6.0 EB05 5.2 · IC025 +2.3 3/3 methods agree | Reporting / coding artifact | serious PRR 4.6 | no trial data cached |
| Irritability | 44 | 6.2 4.6–8.3ROR 6.3 · χ² 185 / p 2e-42 | 5.8 EB05 4.5 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.9 | no trial data cached |
| Gamma-glutamyltransferase increased | 16 | 6.1 3.7–9.9ROR 6.1 · χ² 63 / p 1e-15 | 5.2 EB05 3.4 · IC025 +1.6 3/3 methods agree | Lab value / disease marker | serious PRR 4.5 | no trial data cached |
| Hypokinesia | 10 | 5.8 3.1–10.8ROR 5.8 · χ² 35 / p 2e-9 | 4.7 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Hernia | 13 | 5.7 3.3–9.8ROR 5.7 · χ² 46 / p 7e-12 | 4.8 EB05 3.0 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 | no trial data cached |
| Drug reaction with eosinophilia and systemic symptoms | 17 | 5.6 3.5–9.0ROR 5.6 · χ² 60 / p 5e-15 | 4.9 EB05 3.3 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | no trial data cached |
| Panic attack | 24 | 5.5 3.7–8.3ROR 5.6 · χ² 85 / p 1e-20 | 5.0 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Joint injury | 14 | 5.5 3.3–9.3ROR 5.5 · χ² 47 / p 3e-12 | 4.7 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 | no trial data cached |
| Sedation | 17 | 5.5 3.4–8.8ROR 5.5 · χ² 58 / p 1e-14 | 4.8 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).
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 | 367 | 27.0 24.6–29.7ROR 31.5 · χ² 9,192 / p <1e-300 | 26.9 EB05 24.7 · IC025 +4.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 19.2 | no trial data cached |
| Somnolence (drowsiness) | 157 | 6.6 5.7–7.7ROR 7.0 · χ² 744 / p 3e-164 | 6.5 EB05 5.7 · IC025 +2.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.6 · ♀ 34% (drug 58%) | no trial data cached |
| Generalised tonic-clonic seizure | 149 | 77.4 66.2–90.5ROR 82.3 · χ² 11,068 / p <1e-300 | 76.0 EB05 66.3 · IC025 +5.7 3/3 methods agree | Not in label — unassessed | serious PRR 53.0 | no trial data cached |
| Drug interaction | 116 | 6.2 5.2–7.4ROR 6.4 · χ² 500 / p 5e-111 | 6.0 EB05 5.2 · IC025 +2.3 3/3 methods agree | Reporting / coding artifact | serious PRR 4.6 | no trial data cached |
| Treatment failure | 116 | 11.9 10.0–14.2ROR 12.5 · χ² 1,153 / p 6e-253 | 11.8 EB05 10.1 · IC025 +3.2 3/3 methods agree | Reporting / coding artifact | serious PRR 15.8 · 96% clinician | no trial data cached |
| Epilepsy | 108 | 29.9 24.9–36.0ROR 31.2 · χ² 2,983 / p <1e-300 | 29.7 EB05 25.3 · IC025 +4.4 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 21.0 | no trial data cached |
| Status epilepticus | 102 | 76.6 63.3–92.7ROR 79.9 · χ² 7,472 / p <1e-300 | 74.9 EB05 63.5 · IC025 +5.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 54.4 · 100% clinician | no trial data cached |
| Ataxia | 80 | 56.9 45.9–70.7ROR 58.8 · χ² 4,313 / p <1e-300 | 55.8 EB05 46.3 · IC025 +5.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 42.7 · ♀ 36% (drug 58%) · 97% clinician | no trial data cached |
| Aggression | 79 | 13.3 10.7–16.5ROR 13.7 · χ² 886 / p 5e-195 | 13.1 EB05 10.8 · IC025 +3.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.7 | no trial data cached |
| Convulsion (seizure) | 74 | 10.8 8.6–13.5ROR 11.1 · χ² 646 / p 7e-143 | 10.5 EB05 8.6 · IC025 +2.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.6 | no trial data cached |
| Cognitive disorder | 52 | 9.4 7.2–12.3ROR 9.6 · χ² 384 / p 1e-85 | 9.0 EB05 7.1 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 · 96% clinician | no trial data cached |
| Drug resistance | 46 | 15.1 11.3–20.1ROR 15.4 · χ² 592 / p 5e-131 | 14.9 EB05 11.5 · IC025 +3.2 3/3 methods agree | Reporting / coding artifact | serious PRR 11.9 · 98% clinician | no trial data cached |
| Irritability | 44 | 6.2 4.6–8.3ROR 6.3 · χ² 185 / p 2e-42 | 5.8 EB05 4.5 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.9 | no trial data cached |
| Suicidal ideation (thoughts of suicide) | 38 | 3.5 2.5–4.8ROR 3.5 · χ² 65 / p 3e-16 | 3.4 EB05 2.6 · IC025 +1.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.6 · ♀ 19% (drug 58%) | no trial data cached |
| Abnormal behaviour | 37 | 7.8 5.7–10.8ROR 7.9 · χ² 214 / p 1e-48 | 7.3 EB05 5.5 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 | no trial data cached |
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.
- Generalised tonic-clonic seizure — n=149, PRR 77.4
- Myoclonus — n=34, PRR 24.1
- Grand mal convulsion — n=22, PRR 19.8
- Encephalopathy — n=34, PRR 11.7
- Toxic epidermal necrolysis — n=20, PRR 11.2
- Psychotic disorder — n=36, PRR 10.3
- Altered state of consciousness — n=25, PRR 9.8
- Cognitive disorder — n=52, PRR 9.4
- Abnormal behaviour — n=37, PRR 7.8
- Depressed level of consciousness — n=33, PRR 7.0
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 Ethosuximide?
In FDA FAERS, the most frequently co-reported reaction terms for Ethosuximide are seizure, somnolence, generalised tonic-clonic seizure, epilepsy, status epilepticus, ataxia. 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 Ethosuximide have an FDA boxed warning?
No. The FDA label retrieved for Ethosuximide has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Ethosuximide 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 43fdfd16-c723-452a-9c1d-accf6f7c622e, effective 20241009; matched on
openfda.generic_name.exact:"ETHOSUXIMIDE") - 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, 105 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
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.