Patient perspectives when switching from Cosopt(®) (dorzolamide-timolol) to Azarga™ (brinzolamide-timolol) for glaucoma requiring multiple drug therapy.

Background: This study aimed to determine the impact of switching patients requiring multiple drug treatment from the dorzolamide-timolol fixed combination to the brinzolamide-timolol fixed combination and potential effects on tolerability and compliance.

Methods: Patients were switched from dorzolamide-timolol to brinzolamide-timolol and questioned within a period of 4-26 weeks. Questions were asked to confirm if a specific side effect had been experienced, and then a numerical comparison between the two types of eye drop was made.

Results: Thirty-one consecutive patients (12 males and 19 females aged 41-89 years) successfully completed the questionnaire. Comparison of the severity and chronicity of the side effects of the two types of fixed-combination eye drops showed that brinzolamide-timolol caused significantly less stinging for a shorter amount of time than dorzolamide-timolol; it also produced less eye redness for a significantly shorter amount of time. Brinzolamide-timolol produced more blurring, although the length of time this was present was similar to that for dorzolamide-timolol. No differences between the two eye drops were found for taste, overall impression, and likelihood of compliance.

Conclusion: Our study confirms the findings of other researchers pertaining to the side effect profile of brinzolamide-timolol after switching from dorzolamide-timolol, which is a reduction in stinging but an increase in blurred vision. The advantage of one eye drop over the other then becomes patient-specific, depending on which side effect they find most tolerable. We suggest that both eye drops are acceptable choices in treating patients with glaucoma, and are interchangeable if compliance becomes an issue because of a specific side effect of one eye drop or the other.