Paraldehyde
| Evidence Level: L5 | Predicted Indications: 6 |
Table of Contents
Paraldehyde: From Historical Sedative-Hypnotic Use to Irritable Bowel Syndrome
One-Sentence Summary
Paraldehyde has no formally recorded original indication or UK marketing authorisation in this evidence pack; historically it was used as a central nervous system depressant (sedative-hypnotic/anticonvulsant) before being superseded by benzodiazepines. The TxGNN model’s top-ranked prediction is Irritable Bowel Syndrome, but this association is supported by zero clinical trials and zero publications, and the evidence pack itself flags the mechanistic link as implausible.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | No formal indication data available; historically used as a sedative-hypnotic/anticonvulsant (drug is not currently marketed in the UK) |
| Predicted New Indication | Irritable Bowel Syndrome |
| TxGNN Prediction Score | 99.97% |
| Evidence Level | L5 |
| UK Market Status | Not marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available (data gap DG002). Based on the information in this evidence pack, paraldehyde is a classical GABA-A receptor agonist with central nervous system depressant activity, historically used as a sedative-hypnotic agent prior to being replaced by benzodiazepines due to toxicity concerns (metabolic acidosis, dependence potential, and formulation/storage issues).
For the top-ranked predicted indication, irritable bowel syndrome, the evidence pack explicitly states that no clear mechanistic link exists: paraldehyde’s systemic CNS-depressant action has no established connection to the gut motility and visceral hypersensitivity pathophysiology underlying IBS, and there is no clinical trial or literature evidence to support this association. This prediction should be treated as a likely model artefact arising from broad clustering of sedative-class drugs, rather than a biologically plausible repurposing candidate.
Of the six candidates in this evidence pack, only insomnia (rank 6) has a coherent mechanistic rationale — paraldehyde’s GABA-A agonism is directly relevant to sleep induction, and it was historically used clinically for this purpose — and it is the only candidate with any supporting literature (one review, L3 evidence level). This candidate may warrant more attention than the top-ranked IBS prediction, despite its lower TxGNN score.
Clinical Trial Evidence
Currently no related clinical trials registered
Literature Evidence
Currently no related literature available
UK Market Information
Paraldehyde is not currently authorised for marketing in the UK (market status: not marketed; 0 marketing authorisations on record). No licence or product data is available in this evidence pack.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Note: This evidence pack flags a Blocking data gap (DG001) — TFDA/MHRA label warnings and contraindications are currently unavailable, which prevents progression to the S1 safety review stage.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence level for the top-ranked indication (irritable bowel syndrome) is L5 — a model prediction only, with no supporting clinical trials or literature, and the pack itself states there is no plausible mechanistic link. Safety data (warnings, contraindications) are also unavailable, blocking formal safety evaluation.
To proceed, the following is needed:
- TFDA/MHRA product label data (warnings and contraindications) — Blocking gap (DG001), remediation: download and parse SmPC PDF from TFDA
- Detailed mechanism of action (MOA) data — High-priority gap (DG002), remediation: query DrugBank API
- Independent pharmacological/clinical review of the IBS hypothesis before further investment, given the internal rationale already rates it as implausible
- Consideration of insomnia (rank 6, L3 evidence, plausible GABA-A mechanism) as a better-supported alternative candidate for further investigation
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.