Brimonidine
Brimonidine (Alphagan) lowers pressure inside the eye, used for Open-angle Glaucoma and Ocular Hypertension. Two Allergan eye drops are on this shelf: Alphagan, brimonidine on its own, and Combigan, which pairs it with the beta-blocker timolol.
Key points
- Brimonidine is an alpha-2 adrenergic agonist that reduces elevated eye pressure, whether or not glaucoma is the cause.
- Combigan is a fixed-dose combination of brimonidine and timolol; Alphagan contains brimonidine alone. Both are 5 ml eye-drop bottles in the Eye Care catalogue.
- The medicine must not be used in neonates or infants under two, and children aged two to seven need close monitoring because of how often it causes drowsiness.
Common questions about brimonidine
Why does Combigan pair brimonidine with timolol?
The two active substances lower eye pressure through different routes. Brimonidine acts on alpha-2 receptors; timolol blocks beta-adrenergic receptors. The label states that their combined effect reduces pressure more than either compound given alone, which is why the brimonidine/timolol combination exists as a distinct product from Alphagan.
Can these eye drops affect the rest of the body?
Yes. Although applied to the eye, the timolol in Combigan can be absorbed into the bloodstream, so the same reactions seen with oral beta-blockers may occur. This is why Combigan is contraindicated in people with asthma, severe chronic obstructive pulmonary disease, a slow heart rate, or certain heart conditions. Alphagan, containing brimonidine alone, does not carry the beta-blocker component.