Glaucoma drugs

1. Alpha adrenergic agonists
Alpha adrenergic agonists are a class of medications used in the treatment of glaucoma
These medications work by reducing the production of aqueous humor (the fluid inside the
eye) or by increasing its outflow, thereby lowering IOP.
In the context of glaucoma treatment, alpha adrenergic agonists primarily refer to two
medications: brimonidine and apraclonidine. These drugs target alpha adrenergic receptors
in the eye, specifically the alpha-2 receptors, to achieve their therapeutic effects.
Apraclonidine (ALFADROPS DS 1% eyedrops)
• Does not cross BBB
• When applied topically lowers i.o.t by 25%
• Decreases aqueous production by primary alpha2 and subsidiary alpha1 action on ciliary body
• Itching, lid dermatitis, follicular conjunctivitis, mydriasis ,eyelid retraction, dryness of mouth and nose are
common side effects
• Used to control short term spikes of i.o.t after laser trabeculoplasty or iridotomy

2. Brimonidine (BRIMODIN-P 0.15% eyedrops)
• More alpha2 selective and more lipophilic than apraclonidine
• Lowers i.o.t by 20 – 27% by reducing aqueous production and increasing uveoscleral flow
• Side effects are similar to apraclonidine but less frequent due to weaker alpha1 action
• Used for both short term and long term control of glaucoma

3. Miotics
Till the 1970, topical pilocarpine and AChE were standard anti glaucoma drugs,
but now only used as a last option due to its several drawbacks, such as –
1. Change in pupil size
2. Dimunition of vison in dim light and in patients with cataract
3. Induced myopia
4. Headache and brow pain due to constant spasm of ciliary muscles
5. Fluctuations in i.o.t
In open angle glaucoma, they lower i.o.t by increasing ciliary muscle tone
thereby improving patency of trabeculae.

4. Carbonic Anhydrase Inhibitor
Acts by reduction of aqueous formation by limiting generation of bicarbonate
ions in the ciliary epithelium.
Include Acetazolamide and Dorzolamide
Acetazolamide
• Supplements ocular hypotensive drugs for short term indications
• Side effects include – paresthesia, anorexia, hypokalemia, acidosis, malaise and
depression
Dorzolamide (DORZOX 2% eyedrops)
• Circumvents side effects of acetazolamide
• Lowers i.o.t by 20%
• Side effects include – ocular stinging, burning, itching, corneal edema and
bitter taste

5. MECHANISM
What happens in angle closure glaucoma ?
Mydriasis occurs in eye with narrow iridocorneal
angle and iris makes contact with lens blocking
aqueous outflow. On top of that pressure builds up
behind the iris which bulges forward and closes the
iridocorneal angle.
What happens in open angle glaucoma ?
A genetically predisposed disease affects the patency
of trabecular meshwork, which causes i.o.t to rise
insidiously and progressively.