Betaxolol
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Betaxolol: From Hypertension and Glaucoma to Primary Hereditary Glaucoma
One-Sentence Summary
Betaxolol is a beta-1 selective blocker originally used for hypertension, open-angle glaucoma and ocular hypertension. The TxGNN model's top-ranked prediction is primary hereditary glaucoma (score 99.7%), but no clinical trials or publications support this specific term. The best-supported related prediction, open angle glaucoma (2 Phase 3 trials, 18 publications), overlaps with betaxolol's existing use rather than being a true new indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Hypertensive disorder, hypertension, open-angle glaucoma, ocular hypertension (the Singapore licence record contains no indication text) |
| Predicted New Indication | Primary hereditary glaucoma |
| TxGNN Prediction Score | 99.74% |
| Evidence Level | L5 (for primary hereditary glaucoma); L1 for the related open angle glaucoma prediction |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 1 |
| Recommended Decision | Hold (primary hereditary glaucoma); Proceed with Guardrails (open angle glaucoma, an existing use) |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on known pharmacology, betaxolol is a beta-1 selective adrenergic antagonist. In the eye, it lowers intraocular pressure (IOP) by reducing aqueous humour production. Systemically, it lowers blood pressure and heart rate.
The top prediction, primary hereditary glaucoma, is probably driven by betaxolol's established IOP-lowering effect in other glaucoma types. No evidence was found in a hereditary or congenital glaucoma population, so this remains a model extrapolation only.
The strongly supported predictions (glaucoma 1, open angle; open angle glaucoma) largely match betaxolol's existing use, so they confirm current practice and are not new repurposing opportunities. Other predictions, such as malignant renovascular hypertension, pulmonary hypertension and closed-angle glaucoma, appear to arise from shared "hypertension" or "glaucoma" terms in the knowledge graph. Their mechanistic fit is weak, and some carry clinical concerns (for example, beta-blockers are generally used cautiously in pulmonary arterial hypertension).
Clinical Trial Evidence
No clinical trials are registered for the top-ranked prediction, primary hereditary glaucoma. Trials for the related prediction open angle glaucoma are listed below.
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT02617459 | Phase 3 | Completed | 366 | Randomised, open-label, positive-controlled trial of levobetaxolol eye drops in Chinese patients with primary open-angle glaucoma or ocular hypertension. Levobetaxolol is the S-enantiomer, not racemic betaxolol. |
| NCT00000132 | Phase 3 | Unknown | Not reported | Early Manifest Glaucoma Trial (EMGT): immediate IOP-lowering treatment versus late or no treatment in newly detected open-angle glaucoma. Betaxolol was combined with laser trabeculoplasty, so its effect is not isolated. |
Literature Evidence
No literature was found for primary hereditary glaucoma. The table below shows the most relevant publications for open angle glaucoma.
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 26526633 | 2016 | Systematic review / network meta-analysis | Ophthalmology | Compared first-line medications for primary open-angle glaucoma and ocular hypertension and ranked them |
| 12365904 | 2002 | RCT (EMGT) | Arch Ophthalmol | Lowering IOP slowed progression of newly detected open-angle glaucoma |
| 10571351 | 1999 | RCT design/baseline | Ophthalmology | Design and baseline data of the EMGT |
| 2202584 | 1990 | Review | Drugs | Betaxolol 0.5% reduces IOP by 13–30%, comparable to timolol; main side effect is transient local stinging |
| 8773166 | 1996 | Review | Ann Pharmacother | Compared ocular beta-blockers on systemic effects, tolerability and cost |
| 2898859 | 1988 | Randomised double-masked study | Acta Ophthalmol | Betaxolol and timolol 0.5% gave similar IOP reductions over 26 weeks (−6.3 vs −7.2 mmHg) |
| 11039742 | 2000 | Comparative clinical study | J Glaucoma | Brimonidine 0.2% versus betaxolol 0.25%: clinical success rates and quality of life |
| 9671427 | 1998 | Clinical study | J Ocul Pharmacol Ther | Betaxolol for diurnal IOP control in POAG and normal-tension glaucoma |
| 11755834 | 2002 | Randomised double-masked | Am J Ophthalmol | Six-month comparison of unoprostone with timolol and betaxolol |
| 2874783 | 1986 | Clinical study | Arch Ophthalmol | Epinephrine added to betaxolol lowered IOP further, from 24.5 to 19.4 mmHg at one week |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN12621P | BETAC FILM COATED TABLET 20 mg | Tablet, film coated (oral) | Not listed in the licence record |
The only registered product is an oral tablet. The glaucoma predictions generally involve eye drops, and no ophthalmic betaxolol product appears in the Singapore data, so route compatibility needs to be assessed.
Safety Considerations
- Contraindications flagged in the knowledge graph (these come from drug-disease relationships, not from the package insert): asthma, pulmonary emphysema and other bronchial disease; atrioventricular block; diabetes mellitus, diabetic ketoacidosis and hypoglycaemia; myasthenia gravis; phaeochromocytoma and related tumours; kidney, liver and gallbladder disease; psoriasis; and anxiety or dysthymic disorders.
- Drug interactions: 100 interactions were found in the interaction database, and 20 are listed in the data compiled for this report, mostly Moderate and some Minor. Moderate examples include epinephrine, corticosteroids (hydrocortisone, dexamethasone, betamethasone, budesonide, triamcinolone), atropine, hyoscyamine, bupropion, morphine, acetohexamide and several calcium salts. Minor examples include acetylsalicylic acid, aluminium hydroxide and attapulgite.
- Class-related cautions for the glaucoma use: systemic beta-blocker effects (bradycardia, AV block, decompensated heart failure, severe asthma or COPD). Ocular betaxolol also lowers IOP somewhat less than non-selective beta-blockers and prostaglandin analogues.
Please refer to the package insert for the official warnings and contraindications.
Conclusion and Next Steps
Decision: Hold (for the top-ranked prediction, primary hereditary glaucoma)
Rationale:
- The high TxGNN score (99.7%) is not backed by any trial or publication, and the prediction is likely an extrapolation from betaxolol's known IOP-lowering action in other glaucomas. Evidence level is L5.
- The open angle glaucoma prediction has L1-level support and merits Proceed with Guardrails, but it largely duplicates betaxolol's existing indication and is not new repurposing.
- The other predictions (malignant hypertensive conditions, pulmonary hypertension, closed-angle glaucoma, obsolete or very rare terms) lack evidence or are clinically implausible, so they stay on Hold.
To proceed, the following is needed:
- Package insert warnings and contraindications for the registered Singapore product
- Detailed mechanism of action data
- Direct clinical or genetic-cohort evidence for betaxolol in hereditary or congenital glaucoma
- Assessment of route compatibility, since the registered product is oral and glaucoma treatment typically needs an ophthalmic formulation
- A systemic beta-blocker safety screen (cardiac, respiratory and diabetic risks) before any new use
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.