Latanoprost versus timolol gel-forming solution once daily in primary open-angle glaucoma or ocular hypertension.

Background: To compare the efficacy and safety of latanoprost and timolol gel-forming solution (GFS).

Methods: This was a randomized, crossover, investigator-masked, active-control study of patients with primary open-angle glaucoma and ocular hypertension. Patients received either once-daily 0.5% timolol GFS (n=40) or once-daily 0.005% latanoprost (n=35) for 8 weeks (period 1). Patients were then crossed over to the other medication and treated for another 8 weeks (period 2). Intraocular pressure (IOP) was determined every 2 hours from 8:00 to 20:00 at baseline and weeks 8 and 16. Safety was assessed by visual acuity, slit-lamp biomicroscopy, and adverse event reports.

Results: During period 1, reduction in mean (SD) diurnal IOP was significantly greater in latanoprost-treated patients (-6.9 [3.0] mm Hg) than in timolol GFS-treated patients (-5.5 [2.4] mm Hg), p=0.034. There was also a significant reduction in IOP from baseline after switching from timolol GFS to latanoprost (p<0.001), not observed when patients were switched from latanoprost to timolol GFS. After results from each drug's treatment periods were combined between treatment arms, latanoprost reduced IOP more (-6.9 [2.9] mm Hg) than did timolol GFS (-6.2 [2.7] mm Hg), p=0.018. Hyperemia was the most common adverse event in both treatment groups, with 5 incidences in timolol GFS-treated patients, and 10 in latanoprost.

Interpretation: Latanoprost is more effective than timolol GFS in reducing IOP, and patients switched from timolol GFS to latanoprost have a further significant reduction in IOP.