BRIMONIDINE

 BRIMONIDINE

BRAND NAME:- ALPHAGAN-P ,BRIMODIN - P 0.15% eye drops,IOBRIM 0.2% eye drops.

BRIMONIDINE is clonidine congener is more an alpha-2 adrenergic agonist used to treat glaucoma and ocular hypertension, as well as facial erythema in rosacea. 

PHARMACODYNAMIC:-

This clonidine congener is more an alpha2 selective and more lipophilic than apraclonidine. It lowers i.o.t. by 20-70% by reducing aqueous production and by increasing uveoscleral flow. Peak effects on i.o.t. occurs after 2 hours . Allergic conjunctivitis and other ocular side effects are similar to but less frequent than with apraclonidine. Because of weaker an alpha1 action, side effects like mydriasis,eyelid retraction, conjunctival blanching followed by hyperemia are less prominent, but dry mouth, sedation and a small fall in BP have been noted.

BRIMONIDINE is indicated both for short - term (prophylaxis of i.o.t. spikes post laser / post surgery) as well as long - term use in Glaucoma. It is generally used for add on therapy only.

MECHANISM OF ACTION:-

Brimonidine is an α2 adrenergic agonist.

α2 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 α2 agonist activity results in vasoconstriction of blood vessels (as opposed to central α2 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 α adrenergic stimulation. This may lead to relaxed ciliary muscle and increased uveoscleral outflow. 

USED:-

Brimonidine is used to relieve redness in the eyes caused by minor eye irritations (such as smog, swimming, dust, or smoke). 

SIDE EFFECTS:-

Erythema (skin redness), Blurred vision, Dryness in mouth, Burning sensation in eye, Stinging in the eyes, Flushing (sense of warmth in the face, ears, neck and trunk), Headache, Fatigue, Corneal staining. 

DOSE :- 1 drops in each eye TDS. As directed by your doctor.