Doxazosin
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Doxazosin: From Hypertension and Benign Prostatic Hyperplasia to Migraine Disorder
One-Sentence Summary
Doxazosin is an alpha-1 adrenergic blocker originally used to treat hypertension and benign prostatic hyperplasia. The TxGNN model predicts it may be effective for migraine disorder, but there are no registered clinical trials and only 1 publication (a small case series) supporting this direction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Hypertension; benign prostatic hyperplasia (the approved indication text on the Singapore licence is not available, so these come from the knowledge graph) |
| Predicted New Indication | Migraine disorder |
| TxGNN Prediction Score | 99.20% |
| Evidence Level | L5 (model prediction with only a small uncontrolled case series; no trials) |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 1 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on known pharmacology, doxazosin is an alpha-1 adrenergic receptor antagonist. It relaxes vascular smooth muscle (lowering blood pressure) and prostatic smooth muscle (easing urinary symptoms).
The link to migraine is plausible but indirect. Adrenergic signalling and vascular tone regulation have been proposed to contribute to migraine, and other agents acting on the adrenergic system (for example propranolol and clonidine) are used for prophylaxis. The very high TxGNN score is a computational prediction only and is not backed by trial data. Mechanistic similarity between the original and new indications has not yet been assessed.
Other predictions from the model, such as migraine with brainstem aura, are likely inherited from the general migraine node. Predictions in hair disorders, congenital malformation syndromes and kyphoscoliotic heart disease have no identifiable mechanistic link and appear to be knowledge-graph artefacts. They are not pursued in this report.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 9074296 | 1997 | Review (small case series) | Headache | Ten migraine patients in a neurology practice were given terazosin or doxazosin. Nearly all had fewer or milder migraines, but 5 stopped the drug because of side effects. No serious adverse reactions were reported. |
This is a single, very small, uncontrolled report. It is hypothesis-generating only.
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN05014P | CARDURA TABLET 2 mg | Tablet (oral) | Not available in the data compiled |
Manufacturer: Pfizer Manufacturing Deutschland GmbH. This is the only valid single-ingredient registration.
Safety Considerations
Contraindications / cautions from the drug–disease knowledge graph (these come from the knowledge graph, not from the package insert): multiple system atrophy, postural orthostatic tachycardia syndrome, orthostatic hypotension, hypotensive disorder, liver failure, liver disease, gallbladder disease, pyloric stenosis, intestinal obstruction, priapism, and intraoperative floppy iris syndrome.
Of particular relevance to a migraine population:
- Orthostatic and general hypotension are a concern, since blood pressure lowering is the main pharmacological effect.
- In the one small case series, 5 of 10 patients stopped treatment because of side effects.
Drug Interactions: The interaction query found 100 interacting drugs. Most of those shown are Moderate-level:
- Corticosteroids: hydrocortisone, dexamethasone, betamethasone, budesonide, prednisolone, prednisone, triamcinolone
- SGLT2 inhibitors: canagliflozin, dapagliflozin, empagliflozin, ertugliflozin
- Central nervous system (CNS) agents: morphine, opium, bupropion, dronabinol, nabilone
- Clarithromycin
Interactions with calcitriol, clotrimazole and cimetidine are of unknown severity.
The package insert warnings and contraindications for the Singapore-registered product have not been reviewed. Please refer to the package insert.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests mainly on a computational score and a single small, uncontrolled 1997 case series. There are no registered trials, and the mechanistic rationale is indirect. Doxazosin is already marketed in Singapore, which lowers access barriers, but the evidence is not yet sufficient to move forward. The migraine hypothesis may be kept as a research question.
To proceed, the following is needed:
- Singapore package insert warnings and contraindications (a blocking gap for safety screening)
- Detailed mechanism of action data
- A systematic literature search for alpha-1 blockers (e.g., prazosin, terazosin) in migraine prophylaxis, and a check of international trial registries
- Assessment of tolerability, especially hypotension, in migraine patients
- A controlled study (for example, a small randomised pilot) if the literature review supports the hypothesis
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.