Isoflurane
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Isoflurane: From General Inhalation Anaesthesia to Prinzmetal Angina
One-Sentence Summary
Isoflurane is a volatile inhalational anaesthetic, registered in Singapore as an inhalation anaesthetic solution. The TxGNN model predicts it may be effective for Prinzmetal angina, but no clinical trials and no publications support this prediction. It rests on the model score alone.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not stated in the Singapore licence records (product names indicate inhalation anaesthesia) |
| Predicted New Indication | Prinzmetal angina |
| TxGNN Prediction Score | 99.67% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 2 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Isoflurane is a volatile anaesthetic used to induce and maintain general anaesthesia. Its anaesthetic use is established, but the compiled data do not describe a mechanism.
A plausible but unverified link is the vasodilation of vascular smooth muscle that volatile anaesthetics can cause (possibly through calcium channel modulation). Prinzmetal angina is driven by coronary vasospasm, so relaxation of vascular smooth muscle is conceptually related. However, isoflurane can also cause coronary steal and haemodynamic instability. The link is therefore not a supportable therapeutic rationale at this point.
Other predicted indications were also reviewed. Migraine disorder and migraine with brainstem aura have the most literature, at L4 level. These are preclinical studies, plus case reports of general anaesthesia for refractory status migrainosus. They are flagged as research questions rather than treatment recommendations.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available for Prinzmetal angina.
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN08670P | AERRANE INHALATION ANAESTHETIC (Baxter Healthcare Corporation) | Solution | Not stated in the licence record |
| SIN07914P | ISOFLURANE INHALATION (Piramal Pharma Limited) | Solution | Not stated in the licence record |
Safety Considerations
- Disease associations from the knowledge graph (not label text): The TxGNN knowledge graph lists contraindication links to liver disease, gallbladder disease, hypotensive disorder, malignant hyperthermia of anaesthesia, exercise-induced malignant hyperthermia, and Duchenne, Becker and other muscular dystrophies. These should be confirmed against the package insert.
- Drug Interactions: 38 interactions were identified in total. The main ones are:
- Major: Epinephrine
- Moderate: Morphine, Opium
- Many others have an unclassified severity level, including atropine, hydrocortisone, mannitol, pantoprazole, omeprazole, vancomycin, simvastatin, ondansetron, metoclopramide and dexamethasone.
Please also refer to the package insert for full warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The Prinzmetal angina prediction has no trials or publications behind it. Isoflurane can cause hypotension and coronary steal, and the knowledge graph lists hypotensive disorder as a contraindication. There is no basis to advance the prediction.
To proceed, the following is needed:
- Singapore package insert warnings and contraindications (HSA)
- Mechanism of action data for isoflurane
- Preclinical or clinical evidence on coronary vasospasm
- Assessment of whether a hospital-only anaesthetic could realistically serve this indication
- Separately, a focused review of the migraine and status migrainosus signal, which is the only area with indirect supporting data
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.