Article: Dry eye issues for glaucoma patients

I really appreciated this summary of special issues for glaucoma patients with dry eye. I encourage you to read the whole article but here are some excerpts about thne risks of over-exposure to BAK and suggestions for alternatives.

PCON Supersite, May 1, 2008
Keep tear film in mind when treating glaucoma patients with dry eye

From Katherine Mastrota OD MS:

...Benzalkonium chloride, in most ophthalmic preparations, is an effective preservative that can potentiate the effect of antimicrobials. However, as a detergent, chronic administration of BAK-containing medications, such as glaucoma medications, can be deleterious to surface epithelial cells and, perhaps, have far-reaching effects altering the stem cell environment and function. This added insult to a dry eye patient can lead to inflamed, uncomfortable eyes in patients who suffer both disease entities and intolerability of the hypotensive agents....

From Kathy Yang-Williams, OD, FAAO

Benzalkonium chloride is a common ocular preservative that can exacerbate ocular surface disease. Timolol and pilocarpine 2% are available in a nonpreserved unit dose format; however, these medications tend to be more expensive and are less widely available than commercial preparations. Newer medications have replaced BAK with other preservatives that are gentler to the ocular surface. For example, Alphagan P (brimonidine tartrate 0.15%, Allergan) is preserved with Purite, Timoptic XE (0.25% timolol maleate, Merck) is preserved with benzododecinum bromide and Travatan Z (travoprost, Alcon) is preserved with SofZia.

Combination agents such as Cosopt (dorzolamide HCL, timolol maleate, Merck) and Combigan (0.2% brimonidine tartrate, 0.5% timolol maleate, Allergan) provide other options for decreasing ocular surface toxicity because fewer drug applications are required compared to the use of individual component drugs.