betaxolol hydrochloride: clinical use

Prescribing considerations

• Confirm the glaucoma type; betaxolol has little effect on pupil constriction and should not be used alone to manage angle-closure glaucoma.
• Review cardiovascular, respiratory, vascular, diabetic, thyroid, myasthenic and ocular-surface history.
• Minimise systemic exposure with nasolacrimal occlusion or eyelid closure.
• Inform the anaesthetist before surgery because ophthalmic beta blockade can alter responses during anaesthesia.

Contraindications and cautions

• Hypersensitivity to betaxolol or an excipient
• Reactive airway disease including severe asthma, previous severe asthma or severe COPD
• Sinus bradycardia, sick sinus syndrome or sinoatrial block
• Unpaced second- or third-degree atrioventricular block
• Overt cardiac failure or cardiogenic shock

Monitoring

• Intraocular pressure and glaucoma progression
• Ocular irritation, dryness, corneal disease and adherence to administration technique
• Pulse, blood pressure, cardiac symptoms and respiratory symptoms where clinically relevant
• Signs of masked hypoglycaemia in susceptible patients

Clinical pharmacology

Betaxolol is a lipophilic, relatively cardioselective beta-1 antagonist without intrinsic sympathomimetic or significant membrane-stabilising activity. Corneal penetration permits local suppression of aqueous-humour production, although systemic absorption can still occur.

Formulation and product differences

• The selected product is a multidose suspension containing benzalkonium chloride and requires shaking.
• Benzalkonium chloride may irritate dry or damaged eyes and can be absorbed by soft contact lenses.
• Preservative-free single-dose betaxolol suspensions exist as separate products with their own licences and handling instructions.

Eye drops

Route: Ophthalmic

Strengths: 0.25% w/v, 0.5%, 0.5% w/v