Betaxolol
**Betaxolol** is a topical ophthalmic medication primarily used for the management of **glaucoma** in dogs. It is a cardioselective (beta-1) beta-blocker that reduces intraocular pressure by decreasing the production of aqueous humour. It can be used as a monotherapy or in combination with other topical anti-glaucoma medications, such as carbonic anhydrase inhibitors. It is also utilized prophylactically in the unaffected eye of dogs presenting with unilateral primary closed-angle glaucoma. > **Clinical Warning:** Although applied topically, systemic absorption can occur. Use with extreme caution or avoid in patients with uncontrolled heart failure or asthma.
Mechanism: Betaxolol acts as a **beta-1 selective beta-blocker**. It works by blocking **beta-adrenoreceptors** in the ciliary body → decreasing the production of aqueous humour → lowering intraocular pressure (IOP).
Dosing by species
- Management of glaucoma (including prophylactic management in unilateral primary closed-angle glaucoma) · 1 drop per eye · topical · q12h · Not specified · Can be used alone or in combination with other topical glaucoma drugs (e.g., topical carbonic anhydrase inhibitors).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Uncontrolled heart failure
- Asthma
Adverse effects
- Miosis
- Conjunctival hyperaemia
- Local ocular irritation
Drug interactions
- Oral beta-blockers · Additive adverse effects (systemic beta-blockade) · moderate
- Calcium antagonists · Prolonged atrioventricular (AV) conduction times · major
- Digoxin · Prolonged atrioventricular (AV) conduction times · major
Monitoring
- Intraocular pressure (IOP)
- Heart rate and rhythm (due to potential systemic absorption)
- Signs of local ocular irritation
Overdose
**Clinical Pearl:** Overdosage via the ophthalmic route is rare but excessive application may lead to systemic absorption. Signs of systemic beta-blocker overdose include bradycardia, hypotension, and bronchospasm. Treatment is supportive and symptomatic.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.