Brimonidine Hypersensitivity when Switching Between 0.2% and 0.15% Formulations

Purpose: To investigate hypersensitivity rates in patients switched from brimonidine-purite 0.15% to generic brimonidine 0.2%, and to then investigate hypersensitivity rates to re-initiated brimonidine-purite 0.15% in patients who developed hypersensitivity to brimonidine 0.2%. Methods: Ocular hypersensitivity reactions to generic brimonidine 0.2% were identified by retrospective chart review after all Albuquerque Veterans Administration Medical Center patients taking brimonidine-purite 0.15% were switched to generic brimonidine 0.2% due to a facility formulary change. Because brimonidine-purite 0.15% was subsequently re-initiated in some patients who developed hypersensitivity to brimonidine 0.2%, hypersensitivity reactions to re-initiated brimonidine-purite 0.15% were also identified. Results: Three hundred thirteen subjects met inclusion criteria for this study. Of these, 24 [7.7%; 95% confidence interval (CI): 5.0, 11.2] developed hypersensitivity to brimonidine 0.2% after being switched from brimonidine-purite 0.15%. Fifteen of these 24 patients were subsequently instructed to resume use of brimonidine-purite 0.15%; 3 of these 15 (20%; 95% CI: 4.3, 48.1) developed hypersensitivity to brimonidine-purite 0.15%. Conclusion: Our results suggest that the hypersensitivity rate to generic brimonidine 0.2% in previously successful users of brimonidine-purite 0.15% is similar to hypersensitivity rates in brimonidine-naive populations. Additionally, our findings suggest that re-initiation of brimonidine 0.15% may be a reasonable treatment option for patients with brimonidine 0.2% hypersensitivity.