Efficacy and Safety of Switching from Prostaglandin Analog Therapy to Prostaglandin / Timolol Fixed Combination or Prostaglandin / Brimonidine Therapy.

Background: To compare the safety and efficacy between switching to prostaglandin/timolol fixed combination eye drops (PG/timolol FCs) and adding brimonidine to PG analogue monotherapy.

Methods: Eyes of 53 patients with primary open-angle glaucoma or ocular hypertension who were receiving PG analogue monotherapy were included. Participants were randomly divided into two treatment groups: one was prescribed PG/timolol FCs (switched group), and for the other, 0.1% brimonidine was added to the PG analogue (added group). Intraocular pressure (IOP), blood pressure, and pulse rate were measured after 1 and 3 months and compared to baseline values. Participants were also surveyed to determine if they had experienced systemic or topical adverse events at each study visit. IOP changes at 1 and 3 months were compared between groups.

Results: Three months after changing medication, mean IOP was 14.6 ± 2.4 mmHg in the switched group and 13.7 ± 1.8 mmHg in the added group; both were significantly lower than the baseline values (switched group, 16.5 ± 2.7 mmHg; added group, 15.8 ± 2.3 mmHg; both P < 0.001). Neither the mean nor the percentage reductions in IOP were significantly different between groups at 1 and 3 months. In the added group, diastolic blood pressure was lower than that at 1 and 3 months, systolic blood was lower than that at 3 months (P < 0.01). The patients who had experienced systemic or topical adverse events were 53.8% in the added group and 40.7% in the the changed group, which was equivalent between groups (P =0.4142). Three patients (11.5%) in the added group, but none from the switched group, were excluded from analyses because of adverse events (not significant, P = 0.217).

Conclusion: Switching from a PG analogue to PG/timolol FCs or to PG with brimonidine was equally safe (systemically and topically) and effective in reducing IOP. Thus, PG with brimonidine might be appropriate medication in patients who cannot use PG/timolol FCs due to repiratory or circulatory disease.