Objective: To evaluate the efficacy and safety of commercially available latanoprost 0.005% given every evening versus timolol 0.5% and dorzolamide 2% fixed combination (TDFC) given twice daily to white Greeks with primary open-angle glaucoma and ocular hypertensive patients.

Methods: A single-masked, two-center, crossover comparison with two 6-week treatment periods occurring after at least a 3-week medicine-free period. Diurnal curve intraocular pressures were taken at 2:00 AM, 6:00 AM, 10:00 AM, 2:00 PM, 6:00 PM, and 10:00 PM. Methods: Thirty-four subjects with primary open-angle glaucoma or ocular hypertension were enrolled. Methods: Latanoprost 0.005% given every evening and TDFC twice daily. Methods: The primary efficacy variable was diurnal intraocular pressure.

Results: Thirty-three patients completed the study. On the last day of treatment, the mean diurnal intraocular pressure for latanoprost was 15.9 +/- 2.3 mmHg and for TDFC was 15.3 +/- 2.0 mmHg (P = 0.05). Individual time points for intraocular pressure were not statistically different between groups except at the 10:00 PM time point, when the mean for TDFC was 14.6 +/- 2.7 mmHg and for latanoprost was 16.6 +/- 3.1 mmHg (P < 0.006). Eighteen patients overall preferred latanoprost versus 2 patients for the fixed combination, generally because of the greater convenience of once daily dosing. Adverse events were not significantly different between groups except that a bitter taste was found more frequently with TDFC (n = 9) than with latanoprost (n = 0; P = 0.009). Despite screening to exclude intolerance to beta-blockers, a single patient had to discontinue the TDFC because of new-onset asthma.

Conclusions: This study indicates that the 24-hour diurnal intraocular pressure is lowered more, by a small but statistically significant amount, with TDFC compared with latanoprost in primary open-angle glaucoma and ocular hypertensive patients.