Patients' acceptance of a switch from dorzolamide to brinzolamide for the treatment of glaucoma in a clinical practice setting

Background: The first topically active carbonic anhydrase inhibitor, dorzol amide, was developed to circumvent the adverse systemic effects of oral car bonic anhydrase inhibitors. However, its use has been associated with ocula r discomfort. Objective: The present study examined the acceptability of brinzolamide, as measured by patients' ratings and stated preferences, in patients with gla ucoma previously treated with dorzolamide in the clinical practice setting. Methods: This was a prospective, open-label, noncomparative study conducted shortly after the approval of brinzolamide. Ophthalmologists in private pr actice in the continental United States were asked to select patients curre ntly using dorzolamide as their sole or combination therapy for glucoma. Pa tients underwent a screening assessment in which they were asked to rate th eir ocular comfort with dorzolamide on a scale from 1 to 6. Brinzolamide wa s,then substituted for dorzolamide, and patients returned for a follow-up v isit similar to1 to 3 months later. At this visit, patients were asked abou t ocular comfort, their preferred medication, and whether they thought ocul ar comfort influenced their adherence to treatment. Intraocular pressure (I OP) was measured at both visits. Results: Valid visit dates (ie, both baseline and follow-up dates) were ava ilable for 447 of 501 patients from 68 of 73 sites (range, 1-40 patients pe r site). Because not all measurements were available for all patients at ea ch visit, the sample size varied for each measurement. Demographic data wer e not available. The switch to brinzolamide resulted in a mean decrease in IOP of similar to0.8 mm Hg (P < 0.001, paired t test). Sixty-nine percent o f patients (274/397) reported an improvement of <greater than or equal to>1 grade in their comfort rating with brinzolamide versus dorzolamide. The me an (+/- SD) improvement in comfort rating was 1.43 +/- 1.48 grades (P < 0.0 01, Wilcoxon rank sum test). When patients were asked whether their adheren ce to treatment was affected by the occurrence of burning and stinging, 43% (173/399) answered affirmatively Fifty-nine percent (251/424) preferred br inzolamide to dorzolamide. At the end of the study, based on patient prefer ence, physician judgment, and other factors, 73% of responding patients (30 1/410) continued with brinzolamide therapy. Conclusions: In this study, the switch from dorzolamide to brinzolamide res ulted in overall improvements in comfort and ocular hypotensive efficacy. H owever, studies using a more rigorous randomized, controlled, crossover des ign are needed to support these observations.