Summary
Ethosuximide has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in Irritable Bowel Syndrome (IBS) would be drug repurposing rather than first-in-human development. This does not mean it is approved for Irritable Bowel Syndrome (IBS). ClinicalTrials.gov lists 2 registered trials linking Ethosuximide to Irritable Bowel Syndrome (IBS): 1 is currently recruiting; 1 has completed. The most advanced is Phase 3 (NCT04217733). The largest enrolment is 162 participants (NCT02973542). Registration activity spans 2018 to 2019. The literature layer holds 3 publications for this pair: 3 clinical trial publications. Publication years run from 2017 to 2026. These are primary trial reports rather than syntheses, so results have not yet been pooled or graded independently.
The RepurpOS disease-intelligence file for Irritable Bowel Syndrome ranks 228 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: IBS is chronic and remitting; spontaneous 'remission' (symptom resolution without treatment) in ~30-40% at 2 years but symptom recurrence common; 10-20% develop persistent daily symptoms; <10% achieve permanent remission.
Evidence table
| Evidence tier | A · Strong |
|---|---|
| Evidence score | 34.5 (trials 8.5, literature 6.0, tier 15, approved bonus 5.0) |
| Registered trials | 2 total: 1 recruiting, 0 active / not yet recruiting, 1 completed, 0 other |
| Linked publications | 3 (3 clinical trial publications) |
| Agent type | Drug (Small molecule) |
| Development stage (any indication) | Approved |
| Mechanism / class | blocker |
| Data sources | DGIdb |
| Linked via biomarker / target | CACNA1G |
How the evidence score is calculated
- Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
- Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
- The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
- Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
- The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.
Registered clinical trials
| NCT ID | Title | Status | Phase | Enrolment |
|---|---|---|---|---|
| NCT04217733 | Ethosuximide and Pentoxifylline in the Treatment of Abdominal Pain Related to Irritable Bowel Syndrome 2019 | recruiting | Phase 3 | 60 |
| NCT02973542 | Ethosuximide to Treat IBS 2018 | completed | Phase 2 | 162 |
Published literature
- Clinical trial publication Ethosuximide and Irritable Bowel Syndrome-Related Abdominal Pain: A Randomized Clinical TrialKerckhove N, Zerbib F, Chambaz M et al. · JAMA network open · 2026 · PMID 41505133
- Clinical trial publication Open-label pilot study of ethosuximide as adjunctive therapy for relieving abdominal pain related to Irritable Bowel SyndromeEl-Haggar SM, Hegazy SK, M Abd-Elsalam S et al. · Journal of clinical pharmacy and therapeutics · 2022 · PMID 34726293
- Clinical trial publication Assessment of the effectiveness and safety of ethosuximide in the treatment of abdominal pain related to irritable bowel syndrome - IBSET: protocol of a randomised, parallel, controlled, double-blind and multicentre trialKerckhove N, Scanzi J, Pereira B et al. · BMJ open · 2017 · PMID 28720615
Mechanism and notes
Recorded mechanism or class: blocker.
OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target CACNA1G. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is Ethosuximide approved for Irritable Bowel Syndrome (IBS)?
Ethosuximide has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in Irritable Bowel Syndrome (IBS) would be drug repurposing rather than first-in-human development. This does not mean it is approved for Irritable Bowel Syndrome (IBS). Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is Ethosuximide in clinical trials for Irritable Bowel Syndrome (IBS)?
ClinicalTrials.gov lists 2 registered trials linking Ethosuximide to Irritable Bowel Syndrome (IBS): 1 is currently recruiting; 1 has completed. The most advanced is Phase 3 (NCT04217733). The largest enrolment is 162 participants (NCT02973542). Registration activity spans 2018 to 2019.
What does the evidence show for Ethosuximide in Irritable Bowel Syndrome (IBS)?
Ethosuximide has 1 completed trial and 3 linked publications for Irritable Bowel Syndrome (IBS). Completed trials may or may not have posted results; follow the NCT links to check. OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target CACNA1G. The tier describes how well the drug-disease link is documented, not how well the drug works.
Cite this page
Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-05. Page built 2026-10-07.