Brimonidine tartrate is a selective alpha-2 adrenergic receptor agonist used primarily as an ophthalmic solution for the lowering of intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. It reduces aqueous humor production and increases uveoscleral outflow. In the Indian context, it is a first-line or adjunctive therapy, valued for its neuroprotective potential and dual mechanism.
Adult: One drop in the affected eye(s) three times daily, approximately 8 hours apart.
Note: 1. Wash hands. 2. Tilt head back. 3. Gently pull lower eyelid to form a pouch. 4. Instill one drop into the conjunctival sac. 5. Close eyes gently and apply gentle pressure to the nasolacrimal duct (inner corner of eye) for 1-2 minutes to minimize systemic absorption. 6. Do not blink excessively or rinse the eye. 7. Wait at least 5 minutes before instilling any other topical ophthalmic medication.
Brimonidine is a highly selective alpha-2 adrenoceptor agonist. Its primary mechanism for lowering intraocular pressure (IOP) is dual: 1) Reduction of aqueous humor production by vasoconstriction of afferent ciliary body blood vessels, and 2) Increase in uveoscleral outflow. It has minimal effect on trabecular outflow facility.
Pregnancy: Category B (US FDA). Animal studies have shown no evidence of fetal harm at high doses, but no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus. Minimal systemic absorption reduces risk.
Driving: May cause blurred vision, drowsiness, and fatigue. Patients should not drive or operate machinery until they know how the medication affects them, especially after the first dose.
| Monoamine Oxidase Inhibitors (MAOIs) e.g., Phenelzine, Tranylcypromine | Potentiation of systemic alpha-2 agonist effects (hypotension, bradycardia, CNS depression). | Contraindicated |
| Antihypertensives (Beta-blockers, Calcium channel blockers, Diuretics) | Additive hypotensive and bradycardic effects. | Major |
| Cardiac Glycosides (Digoxin) | Potential additive effects on heart rate (bradycardia). | Moderate |
| Tricyclic Antidepressants (TCAs) e.g., Amitriptyline | May antagonize the IOP-lowering effect of brimonidine. | Moderate |
| CNS Depressants (Alcohol, Benzodiazepines, Opioids) | Additive sedative effects (drowsiness, fatigue). | Moderate |
| Other Topical Ophthalmic Agents (Beta-blockers, Prostaglandins) | Additive IOP-lowering effect. Administer at least 5 minutes apart. | Minor |