Purpose: To compare the efficacy and safety of the fixed combination of latanoprost and timolol with those of the fixed combination of dorzolamide and timolol in patients with elevated intraocular pressure (IOP).
Design: Three-month, randomized, parallel group, evaluator-masked, multicenter study.
Participants: Patients with primary open-angle glaucoma or ocular hypertension with elevated IOP insufficiently responsive to monotherapy; 253 randomized: 125 to receive a fixed combination of latanoprost 0.005% and timolol 0.5% once daily, and 128 to receive a fixed combination of dorzolamide 2% and timolol 0.5% twice daily.
Methods: Visits were at screening (current ocular hypotensive therapy was discontinued), 2 weeks (if needed for an IOP-safety check), baseline (randomization), and after 1 and 3 months of therapy. Intraocular pressure was measured in triplicate at 8 am, 12 pm, and 4 pm at each study visit, and diurnal IOP was calculated as the mean value of these recordings. Adverse events were recorded at each visit.
Main outcome measure: The difference between treatment groups in the change in mean diurnal IOP from baseline to month 3.
Results: Mean diurnal IOP levels were similar at baseline. Mean (+/- standard error of the mean) reductions in diurnal IOP from baseline to month 3 were 9.4+/-0.27 mmHg in the latanoprost/timolol fixed-combination group, versus 8.4+/-0.26 mmHg in patients receiving the dorzolamide/timolol fixed combination. The mean difference in diurnal IOP reduction between treatments was 1.00 mmHg (95% confidence interval, 0.31-1.69; P = 0.005) in favor of the latanoprost/timolol fixed combination. Both treatments generally were well tolerated.
Conclusions: The fixed combination of latanoprost and timolol was slightly more effective than that of dorzolamide and timolol in reducing mean diurnal IOP, and both treatments were generally well tolerated.