Combigan is a prescription eye medication that is used to lower intraocular pressure (IOP) in patients with glaucoma or ocular hypertension. It is a combination medication that contains two active ingredients: brimonidine tartrate and timolol maleate. Glaucoma is a group of eye conditions that can cause damage to the optic nerve and lead to vision loss, often due to increased pressure within the eye. Here's how the two active ingredients work: Brimonidine Tartrate: Brimonidine is an alpha/2 adrenergic agonist. It works by reducing the production of aqueous humor (the fluid inside the eye) and increasing the outflow of this fluid. By regulating the balance between fluid production and drainage, brimonidine helps to lower intraocular pressure. Timolol Maleate: Timolol is a beta/blocker that works by decreasing the production of aqueous humor. By blocking certain receptors, timolol reduces the formation of fluid within the eye, which contributes to lowering intraocular pressure.