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E W GLAUCOMA 7 7 prostaglandin appears to provide a modest 2–4 mm Hg in additional IOP reduction. Given the costs, p otential side effects, and inconven- ience of requiring multiple doses per day, it is reasonable to ask whether we should skip single-agent adjunc- tive therapy and move straight to a fixed combination as the first adjunct to a prostaglandin. There are now three fixed com- binations on the market: timolol a nd dorzolamide (available with and without preservatives), timolol and brimonidine, and most recently, brinzolamide and brimonidine. There are compelling reasons to consider a fixed combination for second-line therapy, according to Thomas Patrianakos, DO, Cook County Health and Hospitals System, Chicago. First and foremost, he said, they lower IOP more than any single agent added to a prostaglandin. They may also improve adher- ence. "A fixed combination simpli- fies the regimen, which enhances quality of life," he said. "Fewer drops per day lead to less opportunity for patient error." Fixed combinations have other advantages as well, including a reduction in exposure to excipient ingredients such as preservatives, elimination of the washout effect when drops are instilled too closely together in time, and reduced cost compared to concomitant therapy for many patients with prescription drug benefits. There is a downside, however. "With fixed combinations, adverse effects are additive as well," said Dr. Tanna. Clinical impact There is a shortage of science to guide the selection adjunctive ther- apy when a prostaglandin inade- quately controls IOP. Any single agent from among the beta-blocker, adrenergic agonist or CAI classes is likely to provide a mean IOP reduc- tion in the range of 2–4 mm Hg. Of these options, only CAIs provide additive IOP reduction in the nocturnal period. For patients who require more than 2–4 mm Hg of additional IOP reduction, adding a fixed combination to a prostaglandin may be a reasonable option. EW Editors' note: Dr. Tanna has financial interests with Alcon (Fort Worth, Texas) and Merck (Whitehouse Station, N .J.). Dr. Rosenberg has no financial interests related to this article. Dr. Jones has financial interests with Alcon. Dr. Patrianakos has no financial interests related to this article. C ontact information Jones: l_s_jones@howard.edu Patrianakos: tpatrianakos@cookcountyhhs.org Rosenberg: lrosenberg@northwestern.edu Tanna: atanna@northwestern.edu February 2011 February 2014 72-77 Glaucoma_EW February 2014-DL2_Layout 1 1/30/14 10:56 AM Page 77