Diurnal intraocular pressure and blood pressure with two dosing regimens of brimonidine in normal tension glaucoma

Background. To compare the effects of 2 dosing regimens of brimonidine tartrate 0.2% on diurnal intraocular pressure (IOP) and systemic hemodynamics in patients with normal-tension glaucoma (NTG). Methods. Twenty NTG patients were enrolled and randomized to receive either brimonidine twice daily (BID) for 4 weeks followed by brimonidine 3 times daily (TID) for another 4 weeks, or in reverse order. Diurnal variations of IOP and ocular perfusion pressure (OPP), as well as the 24-hour ambulatory blood pressure (BP) and pulse rate, were evaluated at baseline and after treatment. Baseline and post-treatment data were compared using a paired Student's t test, and treatment effects were compared between regimens using a crossover-designed analysis of variance. Results. Both regimens decreased the mean (p<0.001) and minimum (p<0.001) diurnal IOP, and only the TID regimen decreased the maximum IOP with a marginal significance (p = 0.049). The TID regimen decreased the maximum OPP (p = 0.009) while the BID regimen caused no changes in OPP. No significant difference in IOP or OPP was noted between regimens at each time point. Neither regimen caused changes in BP or pulse rate as assessed using the 24-hour ambulatory monitoring device. Conclusions. The TID regimen of brimonidine produces similar reductions in diurnal IOP for NTG patients as the BID regimen, and it alone decreases the maximum OPP. Neither of the 2 regimens causes exaggerated nocturnal reduction of BP.