What is the use of brimonidine (alpha-2 adrenergic agonist)?

From the Guidelines

Brimonidine is used to treat open-angle glaucoma, ocular hypertension, and facial redness associated with rosacea, with its primary mechanism being a selective α2-adrenergic receptor agonist with strong vasoconstrictive effects. The medication is available in various forms, including ophthalmic solution (eye drops) typically at 0.1%, 0.15%, or 0.2% concentrations for glaucoma and ocular hypertension, and topical gel form (0.33%) for treating facial redness associated with rosacea 1. Some key points about brimonidine include:

• It decreases the production of aqueous humor and increases its outflow, thereby lowering eye pressure in the treatment of glaucoma and ocular hypertension.
• For rosacea, brimonidine tartrate 0.33% gel has been shown to be effective in reducing facial erythema, with benefits seen as early as 30 minutes after application and maximal effects between 3 and 6 hours after application 1.
• Common side effects of brimonidine eye drops include eye irritation, dryness, and allergic reactions, while systemic effects may include drowsiness, fatigue, and dry mouth.
• When using brimonidine eye drops, patients should wait at least 5 minutes between applying different eye medications and should press gently on the inner corner of the eye for 1-2 minutes after application to prevent systemic absorption.
• The use of brimonidine in combination with other medications, such as ivermectin cream 1%, has been shown to have additive benefits in the treatment of rosacea without significant side effects 1.

From the FDA Drug Label

CLINICAL PHARMACOLOGY: Mechanism of Action: Brimonidine tartrate ophthalmic solution 0. 2% is an alpha adrenergic receptor agonist. It has a peak ocular hypotensive effect occurring at two hours post-dosing. Clinical Evaluations: Elevated IOP presents a major risk factor in glaucomatous field loss. The higher the level of lOP, the greater the likelihood of optic nerve damage and visual field loss Brimonidine tartrate has the action of lowering intraocular pressure with minimal effect on cardiovascular and pulmonary parameters.

Brimonidine is used for lowering intraocular pressure in patients with glaucoma or ocular hypertension 2.

• The main goal of using brimonidine is to reduce the risk of optic nerve damage and visual field loss associated with elevated intraocular pressure (IOP).
• Brimonidine has a dual mechanism of action, reducing aqueous humor production and increasing uveoscleral outflow.

From the Research

Uses of Brimonidine

• Brimonidine is a highly selective alpha 2-adrenoceptor agonist used to reduce intraocular pressure (IOP) in the management of open-angle glaucoma and ocular hypertension 3.
• It is used as monotherapy, adjunctive therapy, and replacement therapy in open-angle glaucoma and ocular hypertension 4.
• Brimonidine is effective in lowering IOP by reducing aqueous humour production and increasing aqueous humour outflow via the uveoscleral pathway 3.

Efficacy of Brimonidine

• Brimonidine has been shown to be as effective as timolol 0.5% twice daily in reducing IOP, and superior to betaxolol 0.25% twice daily 3.
• When added to topical beta-adrenoceptor antagonist therapy, brimonidine has additive ocular hypotensive efficacy similar to that of pilocarpine 2% three times daily 3.
• Brimonidine has been shown to be effective in reducing IOP in patients with glaucoma or ocular hypertension, with a mean reduction in IOP of 5.6 to 5.9 mmHg at peak and 3.3 to 3.7 mmHg at trough 3.

Combination Therapies

• A fixed combination of brimonidine and timolol is available in some countries and has been shown to be effective in reducing IOP 4.
• Brimonidine has also been combined with brinzolamide in a fixed-combination formulation, which has been shown to be effective in reducing IOP and is a potential alternative to other fixed-combination medications 5.
• The combination of brimonidine and latanoprost has also been studied, with results showing that brimonidine is as effective as latanoprost in reducing IOP 6.

Safety and Tolerability

• Brimonidine is generally well tolerated, with the most common adverse events being conjunctival hyperaemia, allergic conjunctivitis, and ocular pruritus 4.
• Brimonidine has been shown to be safe and effective in patients with cardiopulmonary disease, although it should be used with caution in individuals with severe cardiovascular disease 3.