Brimonidine/timolol

Brimonidine/timolol, sold under the brand name Combigan among others, is a fixed-dose combination medication eye drop used for the treatment of glaucoma. It is a combination of brimonidine (an α2 adrenergic agonist) and timolol (a β adrenergic blocker).

In 2020, it was the 256th most commonly prescribed medication in the United States, with more than 1 million prescriptions.

Medical uses

Brimonidine/timolol is used to reduce elevated intraocular pressure (IOP) in people with glaucoma or ocular hypertension who need adjunctive or replacement therapy.

Adverse effects

The most common adverse effects affecting 5 to 15% of the patients include allergic conjunctivitis, conjunctival folliculosis, conjunctival hyperemia, eye pruritus, ocular burning, and stinging. 1 to 5% of the patients in clinical trials experienced asthenia, blepharitis, corneal erosion, depression, epiphora, eye discharge, eye dryness, eye irritation, eye pain, eyelid edema, eyelid erythema, eyelid pruritus, foreign body sensation, headache, hypertension, oral dryness, somnolence, superficial punctate keratitis, and visual disturbance.

Contraindications

Contraindications of brimonidine/timolol include the following: reactive airway disease including bronchial asthma, a history of bronchial asthma, severe chronic obstructive pulmonary disease, sinus bradycardia, secondary or third degree atrioventricular block, overt cardiac failure, cardiogenic shock, age less than 2 years, and hypersensitivity to any component of brimonidine/timolol.

Pharmacology

Brimonidine/timolol is composed of brimonidine, a selective alpha-2 adrenergic receptor agonist, and timolol, a non-selective beta-adrenergic receptor inhibitor. Elevated IOP is considered the only modifiable risk factor in the pathogenesis of glaucoma. Brimonidine exerts its ocular hypotensive effect by decreasing aqueous humor production and increasing uveoscleral outflow, while timolol acts by reducing aqueous humor production.