The 24-Hour Effects of Brinzolamide/Brimonidine Fixed Combination and Timolol on Intraocular Pressure and Ocular Perfusion Pressure

To determine the 24-h effects of brinzolamide/brimonidine tartrate 1%/0.2% fixed combination (BBFC) on intraocular pressure (IOP), ocular perfusion pressure (OPP), blood pressure (BP), and heart rate (HR).Sixty subjects with open angle glaucoma (OAG) or ocular hypertension (OHTN) were admitted overnight for 24-h monitoring of IOP, BP, and HR. All subjects underwent the first, baseline 24-h study after washout of all medications, if necessary. Subjects were then randomized to receive either (1) timolol maleate 0.5% twice daily or (2) BBFC 3 times daily. After 4 weeks of treatment, all subjects completed a follow-up 24-h study visit. At each study visit, IOP, BP, and HR were measured every 2 h in the habitual position. OPP was calculated as 2/3[diastolic BP +1/3(systolic BP-diastolic BP)]-IOP.Treatment with BBFC significantly lowered IOP during the diurnal period (-2.7 ± 0.4 mmHg; P < 0.01) and nocturnal period (-0.8 ± 0.3 mmHg; P < 0.01). Timolol similarly reduced IOP during the diurnal period, but did not lower IOP overnight. Over a 24-h period, BBFC achieved a significantly greater IOP reduction than timolol (-0.7 ± 0.4 mmHg; P = 0.04). BBFC failed to achieve an increase in OPP during any time period, while timolol increased OPP during the diurnal period only. A significantly greater reduction in HR occurred in the timolol group.BBFC significantly lowers IOP during both the diurnal and nocturnal periods, but has no effect on OPP. Timolol only lowers IOP during the diurnal period.