Brimonidine / Timolol Fixed Combination

How it works

Brimonidine reduces aqueous humour production and enhances uveoscleral outflow via alpha-2 receptor stimulation, while timolol decreases aqueous production through beta-blockade, providing additive pressure lowering.

Prescribing in practice

• The timolol component contraindicates use in asthma, bronchospasm, severe COPD and significant bradyarrhythmia or uncontrolled heart failure; warn of systemic beta-blocker effects.
• Brimonidine can cause drowsiness, dry mouth and ocular allergic conjunctivitis, and crosses the blood-brain barrier, so it must be avoided in neonates and infants because of the risk of apnoea and CNS depression.
• Caution with concurrent CNS depressants, antihypertensives and monoamine oxidase inhibitors, and advise punctal occlusion to limit systemic absorption.

Monitoring

Monitor intraocular pressure, watch for ocular allergic reactions to brimonidine, and check heart rate and respiratory tolerance in susceptible patients.

Counselling the patient

• Instil twice daily and press on the inner corner of the eye briefly after each dose.
• It may cause tiredness or a dry mouth; take care if driving until you know how it affects you.
• Report a red, itchy or sticky eye, which may indicate an allergic reaction.

Evidence & guidelines

NICE and specialist glaucoma practice endorse fixed alpha-2 agonist/beta-blocker combinations as a step-up option to consolidate dosing and improve adherence.