Doxazosin
| Evidence Level: L4 | Predicted Indications: 2 |
Table of Contents
Doxazosin: Migraine disorder
One-Sentence Summary
Doxazosin is an alpha-1 adrenergic blocker originally used to treat hypertension and benign prostatic hyperplasia (BPH). The TxGNN model predicts it may be effective for migraine disorder, but currently only 0 registered clinical trials and 1 publication (a small 1997 review of 10 patients) support this direction, so it remains a research question.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Migraine disorder |
| TxGNN Prediction Score | 0.9920 |
| Evidence Level | L4 |
| Canada Market Status | Marketed (marketed DINs: 9 of 9) |
| Number of DINs | 9 (marketed: 9) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the data compiled for this report. Based on general pharmacology, doxazosin is a selective alpha-1 adrenergic receptor antagonist. Its efficacy in hypertension and BPH is well established, and it works by relaxing vascular and prostatic smooth muscle.
Adrenergic signalling influences cerebrovascular tone and sympathetic activity, both of which are hypothesised to play a role in migraine. This offers a plausible but indirect rationale for migraine prophylaxis.
The only supporting publication is a 1997 report in which 10 patients in a neurology practice received terazosin or doxazosin. Migraine frequency or severity decreased in all but one patient, but five stopped treatment because of side effects. This is conceptual support only. The very high TxGNN score is a computational signal, not clinical evidence.
A second predicted indication, migraine with brainstem aura, has no trials or literature. It likely reflects closeness to the parent migraine term in the ontology rather than independent evidence.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 9074296 | 1997 | Review | Headache | Ten migraine patients were given terazosin or doxazosin. Nine had fewer or milder migraines, but five discontinued because of side effects. No serious adverse reactions were reported. |
Canada Market Information
| DIN | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 02240588 | APO-DOXAZOSIN | Not available | Not available |
| 02240589 | APO-DOXAZOSIN | Not available | Not available |
| 02240590 | APO-DOXAZOSIN | Not available | Not available |
| 02242728 | TEVA-DOXAZOSIN | Not available | Not available |
| 02242729 | TEVA-DOXAZOSIN | Not available | Not available |
Nine single-ingredient licences are valid in total (APO, TEVA and JAMP brands); the five above are shown as the main ones.
Safety Considerations
- Disease-level contraindication signals (from the knowledge graph, not label text): 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.
- Drug Interactions: The interaction screening returned 100 interactions in total. The listed ones are mostly of Moderate severity, including:
- Corticosteroids (hydrocortisone, prednisone, prednisolone, dexamethasone, betamethasone, budesonide, triamcinolone)
- SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin, ertugliflozin)
- Opioids (morphine, opium)
- Cannabinoids (dronabinol, nabilone)
- Bupropion and clarithromycin
- Interactions with calcitriol, clotrimazole and cimetidine are of unknown severity.
Please refer to the package insert for the official warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence consists of one small, 1997 uncontrolled report and a model prediction, with no registered trials. The mechanism is plausible but indirect, and the patient-reported side-effect burden (5 of 10 discontinued) is a concern. This is a research question rather than a candidate ready for development.
To proceed, the following is needed:
- Controlled clinical data (at least a well-designed Phase 2 trial) of doxazosin for migraine prophylaxis
- A systematic literature search beyond the single identified publication
- Official mechanism of action data
- Health Canada package insert warnings and contraindications, as well as approved indication text and dosage forms for each DIN
- A tolerability and orthostatic hypotension risk assessment for migraine populations, who are often younger and normotensive
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.