Purpose: To evaluate the efficacy and safety of brimonidine 0.2% two or
three times daily versus timolol maleate 0.5% solution twice daily in primary
open-angle glaucoma patients.
Methods: Patients were randomized by Latin square technique to one of
the three treatment sequences in this crossover, prospective double-masked
trial. Each treatment period
consisted of six weeks of chronic dosing followed by a diurnal curve for the
intraocular pressure measured at 8:00, 10:00, 16:00, 18:00, 20:00, 22:00, and
24:00 hours.
Results: 30 patients completed this trial. A statistical difference in diurnal intraocular pressure
existed between brimonidine twice daily (19.2 ± 2.4 mm Hg) and three times
daily (18.0 ± 2.2 mm Hg), and timolol maleate (17.7 ± 2.7 mm Hg, P <
0.005). When groups were compared
by pairs three times daily dosing with brimonidine and timolol maleate both
reduced the pressure more than twice daily brimonidine at every timepoint past
10:00 hours and for the diurnal curve (P < 0.05). In contrast, three times daily brimonidine and timolol
maleate, were statistically similar for the diurnal pressure and each
timepoint, except timolol maleate decreased the pressure more at 16:00 (P =
0.042). Safety was similar between
groups.
Conclusions: This study demonstrates that both timolol maleate twice
daily and brimonidine three times daily provide a similar intraocular pressure
reduction to each other, and a greater decrease in pressure in the late
afternoon and nighttime hours, compared to brimonidine twice daily.