Brimonidine

How it works

It lowers intraocular pressure by reducing aqueous humour production and increasing uveoscleral outflow via stimulation of alpha-2 receptors in the ciliary body.

Prescribing in practice

• Avoid in neonates and young infants, in whom systemic absorption can cause CNS depression, apnoea, bradycardia and hypotension.
• Commonly causes ocular allergy and conjunctival hyperaemia, which may necessitate discontinuation with prolonged use.
• Use with caution in cardiovascular disease, cerebral or coronary insufficiency, depression, and orthostatic hypotension.

Monitoring

Monitor intraocular pressure response and watch for local hypersensitivity and, in susceptible patients, systemic alpha-adrenergic effects such as drowsiness and dry mouth.

Counselling the patient

• It can cause drowsiness and fatigue; take care when driving or operating machinery.
• Remove soft contact lenses before instilling and wait before reinserting them.
• Report persistent redness, itching or swelling of the eye, which may indicate an allergic reaction.

Evidence & guidelines

Topical alpha-2 agonists are an established second-line option for lowering intraocular pressure where prostaglandin analogues or beta-blockers are insufficient or unsuitable.