Brimonidine — NZ Medication Guide

What is Brimonidine?

Brimonidine (generic name: brimonidine tartrate) is a medication used primarily for lowering intraocular pressure in open-angle glaucoma and ocular hypertension. Brimonidine eye drops 0.2% (Alphagan) are available in New Zealand on prescription. They are funded by Pharmac for glaucoma management, often as second-line or adjunct therapy.

What is Brimonidine Used For?

Brimonidine is prescribed by healthcare professionals in New Zealand for the following indications:

• Open-angle glaucoma (intraocular pressure reduction)
• Ocular hypertension (elevated eye pressure without glaucoma damage)
• Adjunct therapy when beta-blocker eye drops are insufficient or contraindicated
• Rosacea (topical gel formulation — facial redness, off-label in some countries)

How Does Brimonidine Work?

Brimonidine is a selective alpha-2 adrenoceptor agonist. When applied as eye drops, it reduces intraocular pressure by decreasing aqueous humour production and increasing uveoscleral outflow. It has a dual mechanism of action that makes it useful as monotherapy or in combination with other glaucoma treatments. Unlike beta-blocker eye drops, brimonidine does not affect heart rate or lung function, making it preferable in patients with asthma or bradycardia.

How to Take Brimonidine

Apply one drop of brimonidine 0.2% eye drops into the affected eye(s) twice or three times daily as directed by your ophthalmologist. Press the inner corner of your eye (punctal occlusion) for 1–2 minutes after instillation to reduce systemic absorption. Space doses evenly throughout the day. Do not use with soft contact lenses in place — remove contacts and wait at least 15 minutes before reinserting. Store at room temperature and discard according to the expiry on the bottle.

Common Side Effects

• Ocular stinging or burning on instillation
• Red eye or conjunctival hyperaemia
• Dry eye and itching
• Foreign body sensation
• Drowsiness or fatigue (systemic absorption)
• Dry mouth (systemic absorption)

Serious Side Effects — Seek Medical Attention

• Severe allergic conjunctivitis (allergic reaction to the eye drops)
• Significant systemic sedation — avoid activities requiring alertness (especially in elderly)
• Hypotension — particularly in combination with systemic antihypertensives
• Apnoea in neonates and young infants (contraindicated in children under 2 years)
• Corneal toxicity with prolonged use

Drug Interactions

• CNS depressants (alcohol, sedatives, benzodiazepines) — enhanced sedation due to systemic absorption
• Tricyclic antidepressants — may interfere with brimonidine metabolism; enhanced CNS effects
• MAO inhibitors — CONTRAINDICATED; risk of serious cardiovascular and CNS effects
• Antihypertensives — additive blood pressure lowering effect
• Beta-blocker eye drops — commonly combined for additive IOP reduction; monitor for systemic effects

New Zealand Prescribing Information

In New Zealand, glaucoma management is guided by ophthalmologist specialists. Brimonidine is typically used when prostaglandin analogues (latanoprost) or beta-blocker eye drops are insufficient or not tolerated. The NZ Guidelines for the Management of Glaucoma support combination therapy when monotherapy is inadequate. Regular intraocular pressure monitoring and optic nerve assessment are essential components of glaucoma care.

Frequently Asked Questions

Why do I feel drowsy after using brimonidine eye drops?

Although applied directly to the eye, a small amount of brimonidine is absorbed systemically through the nasolacrimal duct. This systemic absorption can cause drowsiness, fatigue, and dry mouth. Using punctal occlusion (pressing the inner corner of your eye after instilling drops) reduces this absorption significantly. Avoid driving or operating machinery if you experience significant sedation.

Can I use brimonidine eye drops if I have asthma?

Yes — brimonidine is generally safe for patients with asthma or chronic obstructive pulmonary disease (COPD) as it does not affect the airways, unlike timolol (a beta-blocker eye drop). This is one of its key advantages for patients who cannot use beta-blocker eye drops. Always inform your ophthalmologist and prescriber of all your medical conditions when starting any new eye medication.

References & Further Information

The following New Zealand and international resources were used to inform this page:

• New Zealand Formulary — Brimonidine
• Pharmac — Funded Medicines Schedule
• Glaucoma NZ — Understanding Glaucoma Treatment
• Medsafe — Alphagan Eye Drops Data Sheet

Reviewed by a Registered Pharmacist — KiwiMeds New Zealand