The safety and efficacy of unoprostone 0.15% versus brimonidine 0.2%

To compare the efficacy and safety of unoprostone versus brimonidine both given twice daily in ocular hypertensive or primary open-angle glaucoma subjects.

After a 1-month washout period a baseline diurnal curve was measured every 2 hours from 08:00 hours (trough) to 20:00 hours in subjects with a trough intraocular pressure (IOP) and the pressure 24 mmHg. Qualified subjects were randomized to either brimonidine or unoprostone. After 6 weeks of treatment the period 1 diurnal curve was performed. Subjects were then switched to the opposite treatment for 6 weeks and the period 2 diurnal curve was performed.

A total of 33 subjects were included in this study. In the brimonidine-treated group the trough IOP 20.1 +/- 2.8 mmHg was reduced from baseline up to 8 hours after dosing. In the unoprostone-treated group the trough IOP was 19.5 +/- 3.0 mmHg, which was statistically equal to that of brimonidine (p = 0.21), was reduced from baseline for 12 hours after dosing. Brimonidine decreased the IOP statistically more than unoprostone at 10:00 and 12:00 hours (p < 0.0001 and p = 0.02, respectively), while unoprostone reduced the IOP more than brimonidine at 18:00 and 20:00 hours (p = 0.002 and p = 0.05, respectively). Safety levels were similar between groups, but unoprostone caused more ocular stinging than brimonidine (p = 0.008).

This study suggests that twice daily brimonidine demonstrates a statistically greater peak reduction in IOP than unoprostone. However, unoprostone, but not brimonidine, decreased IOP over the complete 12-hour daytime dosing cycle.