24-hour intraocular pressures with brimonidine purite versus dorzolamide added to latanoprost in primary open-angle glaucoma subjects.

Objective

To evaluate the 24-hour efficacy of brimonidine purite versus dorzolamide, each added to latanoprost.

Design

Double-masked, 2-center, prospective, crossover comparison.

Participants

Primary open-angle glaucoma (POAG) subjects.

Methods

Subjects were randomized to brimonidine purite or dorzolamide, each given twice daily, for the first 6-week treatment period after a 6-week latanoprost run-in. Subjects began the opposite treatment for the second 6-week period after a 6-week latanoprost-only treatment between periods. Intraocular pressure (IOP) was measured at 8 am, 12 pm, 4 pm, 8 pm, 12 am, 4 am, and 8 am at each baseline and at the end of each treatment period. This study provided an 80% power that a 1.5-mmHg difference could be excluded between groups if 27 subjects completed the study. A standard deviation (SD) of 2.8 mmHg was assumed.

Main outcome measures

Twenty-four-hour efficacy of intraocular pressures of brimonidine purite versus dorzolamide, each added to latanoprost.

Results

In 31 completed subjects, the baseline mean diurnal 24-hour IOP (+/- SD) was 19.0+/-1.7 mmHg for brimonidine purite and 19.0+/-1.6 mmHg for dorzolamide (P = 0.52). The 8 am IOP after 6 weeks of therapy was 18.4+/-2.1 mmHg for brimonidine purite and 18.9+/-1.9 mmHg for dorzolamide (P = 0.40). The mean diurnal IOP was 16.9+/-1.5 mmHg for brimonidine purite and 16.8+/-1.5 mmHg for dorzolamide (P = 0.66). Dorzolamide caused a more bitter taste (P = 0.01) than brimonidine purite.

Conclusions

This study suggests that brimonidine purite and dorzolamide, added to latanoprost, have similar efficacy and safety in POAG or ocular hypertensive subjects.