Metyrapone
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Metyrapone: From Adrenal Function Testing to Exercise-Induced Malignant Hyperthermia
One-Sentence Summary
Metyrapone is an 11β-hydroxylase (CYP11B1) inhibitor, established for hypothalamic-pituitary-adrenal (HPA) axis testing and management of Cushing’s syndrome. The TxGNN model predicts a possible link to Exercise-Induced Malignant Hyperthermia, but this prediction is supported by 0 clinical trials and 0 publications, and the model’s own mechanistic review found no plausible pharmacological basis for the association.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Adrenal function (HPA axis) testing / Cushing’s syndrome (sourced from evidence-pack mechanistic notes; not confirmed via a formal indications record) |
| Predicted New Indication | Exercise-Induced Malignant Hyperthermia |
| TxGNN Prediction Score | 99.95% |
| 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 in the formal original_moa field. Based on information contained elsewhere in the evidence pack, Metyrapone inhibits 11β-hydroxylase (CYP11B1) in the adrenal cortex, blocking cortisol synthesis; clinically it is used to test HPA axis function and to manage Cushing’s syndrome.
Exercise-induced malignant hyperthermia and the related conditions predicted by the model (malignant hyperthermia susceptibility, King-Denborough syndrome, central core myopathy, multiminicore disease, centronuclear myopathy, familial periodic paralysis, renal tubular acidosis, and anaesthesia-induced malignant hyperthermia) are caused primarily by RYR1 (and occasionally CACNA1S) mutations, which lead to abnormal calcium release from the sarcoplasmic reticulum in skeletal muscle. This is a fundamentally different biological pathway from adrenocortical steroidogenesis.
The evidence pack’s own mechanistic review of all ten ranked candidates concludes that the high TxGNN scores most likely arise from indirect knowledge-graph proximity (for example, via shared “stress/steroid response” or “electrolyte/endocrine” intermediate nodes) rather than genuine pharmacological overlap. No candidate has any supporting clinical, preclinical, or literature evidence, and several rationales explicitly flag a theoretical risk that metyrapone could worsen electrolyte disturbance rather than help (e.g. renal tubular acidosis). This is a mechanistically weak, model-only signal.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available.
UK Market Information
Metyrapone currently holds no active UK marketing authorisations in this evidence pack (market status: Not Marketed; 0 licenses on file). No dosage form or licensed-indication data are available for review.
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 — TFDA/SmPC warnings and contraindications for metyrapone have not yet been retrieved, so no drug-specific safety statements can be made at this stage.)
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests solely on a TxGNN model score (L5, decision stage S0) with no supporting clinical trials or literature, and the evidence pack’s own mechanistic analysis finds no credible biological link between cortisol-synthesis inhibition and RYR1-driven malignant hyperthermia/myopathy pathology. A blocking data gap on safety (TFDA/SmPC warnings) further precludes any safety assessment.
To proceed, the following is needed:
- Confirmed original indication and mechanism-of-action data for metyrapone (currently marked as a data gap)
- TFDA/SmPC warnings and contraindications (Blocking gap — required before any S1 safety screening)
- Preclinical (in vitro/in vivo) evidence exploring any plausible interaction between adrenal steroidogenesis and RYR1-mediated calcium signalling, before this candidate can advance beyond L5
- Continued monitoring for emerging literature or trial registrations, given the complete current absence of clinical/observational evidence across all ten predicted indications in this candidate set
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.