Brimonidine is a drug used as eye drops under the brand names Alphagan and Alphagan-P to treat open-angle glaucoma or ocular hypertension, and as a gel, Mirvaso, for facial skin redness in rosacea.
It acts via decreasing synthesis of aqueous humor, and increasing the amount that drains from the eye through uveoscleral outflow; brimonidine treats reddened skin (erythema) by causing narrowing of blood vessels (vasoconstriction).
Video Brimonidine
Clinical uses
Brimonidine is indicated for the lowering of intraocular pressure in patients with open-angle glaucoma or ocular hypertension. It is also the active ingredient of Combigan along with timolol maleate.
A Cochrane Systematic Review compared the effect of brimonidine and timolol in slowing the progression of open angle glaucoma in adult participants.
In 2013, the FDA approved topical application of brimonidine 0.33% gel (Mirvaso) for persistent facial redness of rosacea.
Maps Brimonidine
Mechanism of action
Brimonidine is an ?2 adrenergic agonist.
?2 agonists, through the activation of a G protein-coupled receptor, inhibit the activity of adenylate cyclase. This reduces cAMP and hence aqueous humour production by the ciliary body.
Peripheral ?2 agonist activity results in vasoconstriction of blood vessels (as opposed to central ?2 agonist activity that decreases sympathetic tone, as can be seen by the medication clonidine). This vasoconstriction may explain the acute reduction in aqueous humor flow. The increased uveoscleral outflow from prolonged use may be explained by increased prostaglandin release due to ? adrenergic stimulation. This may lead to relaxed ciliary muscle and increased uveoscleral outflow.
References
- Mosby's Drug Guide for Nurses (7th edition; Skidmore) 2007.
External links
- Alphagan P (brimonidine tartrate ophthalmic solution) Product Website
- Alphagan P Full Prescribing Information
- Mirvaso (brimonidine topical gel) Product Website
Source of the article : Wikipedia
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