Iohexol
| 證據等級: L5 | 預測適應症: 2 個 |
目錄
Using the txgnn-pipeline skill for context. Now I’ll generate the evaluation report based on the Evidence Pack. This case involves Iohexol (a radiological contrast agent) with TxGNN predictions for insomnia and anxiety — both flagged as L5/Hold with false-positive evidence matches. I’ll apply the report format accordingly.
Iohexol: From Radiological Contrast Agent to Insomnia
One-Sentence Summary
Iohexol is a non-ionic iodinated contrast medium used in radiological imaging procedures (CT, myelography, angiography), functioning purely through physical X-ray absorption rather than pharmacodynamic activity. The TxGNN model predicts it may be effective for Insomnia, with 0 clinical trials and 0 publications directly supporting this direction. A secondary prediction for Anxiety (rank 2, score 99.25%) was also retrieved, but all associated evidence represents confirmed false-positive matches where Iohexol served as a GFR measurement tool or guiding contrast agent — not as a therapeutic agent.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Radiological contrast agent (X-ray, CT, myelography, angiography) |
| Predicted New Indication | Insomnia |
| TxGNN Prediction Score | 99.87% |
| Evidence Level | L5 |
| NL Market Status | Not marketed |
| Number of Authorizations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the Evidence Pack. Based on known pharmacology, Iohexol is a non-ionic, water-soluble iodinated contrast medium. Its sole pharmacological mechanism is physical: the high iodine content absorbs X-rays, enhancing radiological image contrast in target tissues. It has no established receptor-binding activity, no central nervous system pharmacodynamics, and no known interaction with any pathway implicated in sleep regulation.
Insomnia involves dysregulation of GABA-A receptors, adenosine signalling, melatonin pathways, and the hypothalamic–pituitary–adrenal (HPA) axis. Iohexol has no known activity at any of these targets. The TxGNN analysis itself acknowledges this explicitly: the high prediction score most likely reflects knowledge graph noise — for example, spurious associations between iodinated compound nodes and protein nodes unrelated to sleep biology — rather than a genuine biological signal.
There is no mechanistic bridge between contrast agent use and insomnia pathophysiology. Unlike cases where a drug’s known mechanism plausibly extends to a new indication (e.g., a kinase inhibitor repurposed across tumour types), Iohexol’s mechanism is entirely physical and indication-agnostic. This prediction requires a biologically plausible hypothesis before any further evaluation is warranted.
Clinical Trial Evidence
Currently no related clinical trials registered for Iohexol in insomnia.
Note on secondary indication — Anxiety (Rank 2): Six clinical trials were retrieved but all are confirmed false positives (relevance grade C). In each case, Iohexol appeared in the study context either as a GFR measurement tool (iohexol plasma clearance technique) or as an imaging contrast agent for procedural guidance — not as the investigational therapeutic. Anxiety appeared only as a comorbidity measure or adverse event category, not as a primary endpoint being treated. Representative examples:
Trial Role of Iohexol Why It Is a False Positive NCT01053130 GFR measurement tool Bariatric surgery/CKD study; anxiety not a treatment target NCT01629537 Guiding contrast for stellate ganglion block Treatment is nerve block, not Iohexol; PTSD/anxiety as endpoint NCT03736005 GFR measurement tool Critical illness/muscle wasting study; anxiety not an endpoint
Literature Evidence
Currently no related literature available for Iohexol in insomnia.
Note on secondary indication — Anxiety (Rank 2): Six publications were retrieved but all represent false-positive associations. Anxiety or mental symptoms appear incidentally — as side effects of myelography (PMID 2352635), as procedural discomfort descriptors (PMID 8883531), or as patient-reported outcomes in imaging studies — not as a therapeutic target of Iohexol.
Netherlands Market Information
Iohexol currently holds no marketing authorization registered with the CBG-MEB in the Netherlands. No RVG number, SmPC, or PIL is available through the Dutch regulatory database.
For reference: Iohexol-containing products (e.g., Omnipaque®) hold authorizations in other EU member states. A decentralized procedure (DCP) or mutual recognition procedure (MRP) pathway would need to be separately verified for any Netherlands-specific authorization.
Safety Considerations
Please refer to the SmPC (Summary of Product Characteristics) for safety information. No warnings, contraindications, or drug interaction data were available in this Evidence Pack.
Conclusion and Next Steps
Decision: Hold
Rationale: This is a pure model prediction (L5 evidence) with zero supporting clinical trials or literature for insomnia, and all retrieved evidence for the secondary indication (anxiety) consists of confirmed false-positive matches. Iohexol has no pharmacodynamic mechanism relevant to any neurological or psychiatric indication; the high TxGNN score is best explained by knowledge graph artifacts rather than a genuine repurposing signal.
To proceed, the following is needed:
- A biologically plausible hypothesis linking iohexol or iodinated contrast media to sleep or anxiety regulation — none currently exists in the published literature
- A knowledge graph quality audit to investigate why Iohexol scores highly for CNS indications (potential node mis-association in the TxGNN graph)
- Any preclinical (in vitro / in vivo) evidence of CNS-modulating effects before clinical consideration
- Confirmation of Dutch market authorization status via CBG-MEB or EMA centralized procedure review if future development is considered
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.