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

Abstract

Background: The first topically active carbonic anhydrase inhibitor, dorzolamide, was developed to circumvent the adverse systemic effects of oral carbonic anhydrase inhibitors. However, its use has been associated with ocular discomfort.

Objective: The present study examined the acceptability of brinzolamide, as measured by patients' ratings and stated preferences, in patients with glaucoma 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 practice in the continental United States were asked to select patients currently using dorzolamide as their sole or combination therapy for glaucoma. Patients underwent a screening assessment in which they were asked to rate their ocular comfort with dorzolamide on a scale from 1 to 6. Brinzolamide was then substituted for dorzolamide, and patients returned for a follow-up visit approximately 1 to 3 months later. At this visit, patients were asked about ocular comfort, their preferred medication, and whether they thought ocular comfort influenced their adherence to treatment. Intraocular pressure (IOP) was measured at both visits.

Results: Valid visit dates (ie, both baseline and follow-up dates) were available for 447 of 501 patients from 68 of 73 sites (range, 1-40 patients per site). Because not all measurements were available for all patients at each visit, the sample size varied for each measurement. Demographic data were not available. The switch to brinzolamide resulted in a mean decrease in IOP of approximately 0.8 mm Hg (P < 0.001, paired t test). Sixty-nine percent of patients (274/397) reported an improvement of > or =1 grade in their comfort rating with brinzolamide versus dorzolamide. The mean (+/- SD) improvement in comfort rating was 1.43 +/- 1.48 grades (P < 0.001, Wilcoxon rank sum test). When patients were asked whether their adherence to treatment was affected by the occurrence of burning and stinging, 43% (173/399) answered affirmatively. Fifty-nine percent (251/424) preferred brinzolamide to dorzolamide. At the end of the study, based on patient preference, physician judgment, and other factors, 73% of responding patients (301/410) continued with brinzolamide therapy.

Conclusions: In this study, the switch from dorzolamide to brinzolamide resulted in overall improvements in comfort and ocular hypotensive efficacy. However, studies using a more rigorous randomized, controlled, crossover design are needed to support these observations.