Acute and chronic effects of brimonidine 0.2% on intraocular pressure and pulsatile ocular blood flow in patients with primary open-angle glaucoma: An open-label, uncontrolled, prospective study

Background. Brimonidine has been reported to decrease aqueous production an d increase uveoscleral outflow; however, the hemodynamic effects of brimoni dine are still under investigation. Objective: The purpose of this study was to report the acute and chronic ef fects of brimonidine 0.2% on intraocular pressure (IOP) and pulsatile ocula r blood flow (pOBF) in patients with primary open-angle glaucoma (POAG). Methods: Nonsmoking patients aged 45 to 67 years with POAG and normal blood pressure, heart rate, body mass index, and hemorheologic parameters were e nrolled in the study. Brimonidine 0.2% was self-administered twice daily fo r 180 days. IOP and pOBF were determined using Goldmann applanation tonomet ry and the Langham system. All measurements were taken at baseline and 4, 8 , and 12 hours after treatment and were repeated on days 7, 15, 30, 60, 90, 120, 150, and 180 of treatment. Results: Of the 18 eligible patients, 10 (6 men and 4 women) were enrolled (mean age, 51.5 +/-4.39; range, 47-64 years). When measured 12 hours after instillation, mean IOP was significantly reduced by 21.5% (P<0.001) compare d with the baseline value. The greatest decrease in IOP (-23.5%) was observ ed at 8 hours. After 12 hours, a significant increase (P<0.001) in pOBF was measured. A stable IOP reduction (P<0.001 vs baseline), as well as an incr ease in pOBF (P=0.015), was recorded at the subsequent time points. The pOB F increases ranged from 22.5% at day 30 to 9.2% at day 180 of treatment. No evidence of adverse events was found at any time point. Conclusions: In this sample of patients with open-angle glaucoma, brimonidi ne induced a rapid reduction in IOP that was significant even after 6 month s. Moreover, an increase in pOBF was observed from the first day of treatme nt, and remained consistent throughout the study.