bimatoprost + timolol maleate: clinical use

Prescribing considerations

• Confirm insufficient response to an appropriate topical beta-blocker or prostaglandin analogue.
• Assess respiratory and cardiovascular history because timolol is systemically absorbed.
• Use caution with coronary disease, hypotension, first-degree heart block, peripheral circulatory disease, mild or moderate COPD, diabetes, hyperthyroidism and severe allergy history.
• Review macular-oedema and inflammatory risk factors, including aphakia, disrupted posterior lens capsule, previous intraocular surgery, diabetic retinopathy, retinal vein occlusion and intraocular inflammation.
• Safety and efficacy have not been established in children; use has not been studied adequately in renal or hepatic impairment.
• Ensure the anaesthetist knows about ophthalmic timolol before surgery.

Contraindications and cautions

• Hypersensitivity to bimatoprost, timolol, beta-blockers or formulation excipients
• Current or previous bronchial asthma, reactive airway disease 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 visual or optic-nerve status
• Heart rate, blood pressure and cardiorespiratory symptoms in susceptible patients
• Corneal surface in dry-eye disease, compromised cornea or prolonged preserved-drop use
• Macular status where risk factors for macular oedema exist
• Iris pigmentation, eyelash growth and prostaglandin-associated periorbital changes
• Clinical response with another systemic beta-blocker or prostaglandin analogue

Clinical pharmacology

Bimatoprost is a synthetic prostamide that increases trabecular and uveoscleral aqueous-humour outflow. Timolol is a non-selective beta-adrenoceptor antagonist that reduces aqueous-humour formation. Ophthalmic timolol is partly absorbed systemically and is metabolised mainly in the liver, with renal elimination of timolol and its metabolites.

Formulation and product differences

• Selected GANFORT and Aspire multidose solutions contain benzalkonium chloride and are supplied in multidose bottles.
• Benzalkonium chloride can irritate the ocular surface, affect compromised corneas and discolour soft contact lenses.
• Preservative-free single-dose products also exist, but their licensing and handling instructions should be checked against their own product information.

Eye drops

Route: Ophthalmic

Strengths: 0.3 mg/mL + 5 mg/mL