How glaucoma medication works

I recently wrote about the diagnosis of glaucoma and readers were then asking about how their eye drops for the condition work.

The raised pressure within the eye that defines glaucoma and can cause optic nerve damage can be lowered through surgery problematic cases that do not respond to drugs but eyedrops containing one of a range of medications is the first line treatment. Despite the risks to one’s sight, apparently patient compliance with medication is low in many cases.

  • Prostaglandin analogues, such as latanoprost (Xalatan), bimatoprost (Lumigan) and travoprost (Travatan), increase the rate of fluid outflow from the aqueous humor to lower pressure. Bimatoprost also increases trabecular outflow.
  • Topical beta-adrenergic receptor antagonists, such as timolol, levobunolol (Betagan), and betaxolol, decrease aqueous humor production to lower pressure.
  • Alpha2-adrenergic agonists, such as brimonidine (Alphagan) and apraclonidine, work by a dual mechanism, decreasing aqueous humor production and increasing outflow.
  • Less-selective alpha agonists, such as epinephrine, decrease aqueous humor production through vasoconstriction of blood vessels.

Other compounds used in glaucoma include: epinephrines, miotic agents, such as pilocarpine, the acetylcholinesterase inhibitor echothiophate is used in chronic glaucoma, dorzolamide (Trusopt), brinzolamide (Azopt), and acetazolamide (Diamox) and physostigmine.