Purpose: To evaluate the 24 hour efficacy of latanoprost
0.005% given every evening versus timolol 0.5%/dorzolamide 2% fixed combination
(TDFC) given twice daily in newly diagnosed primary open-angle glaucoma (POAG)
and ocular hypertensive (OHT) patients.
Methods:
This is a two centre ongoing prospective, masked, crossover study. To date we have randomized 27 Greek
patients with POAG (N=22) or OHT (N=5).
Patients underwent two six-week treatment periods with latanoprost
0.005% dosed at 20:00 hours and TDFC dosed at 08:00 and 20:00 hours. Diurnal curve pressures were taken at
the end of each treatment period at 06:00, 10:00, 14:00, 18:00, 22:00 and 02:00
hours. Side effects and patients’
preference to medications have also been documented.
Results: The study found that following six weeks of treatment
the mean diurnal intraocular pressure for TDFC was lower than that for
latanoprost (15.3 ± 1.8 vs
16.1 ± 2.2 mm Hg; P = 0.013). With regard to individual timepoints no
difference was observed between the two medication except for the evening
measurement (22:00) when the TDFC provided lower intraocular pressure (14.7 ± 2.5 vs 17.2 ± 3.0; P<0.0001). Adverse events were not significantly different
between latanoprost and TDFC (P > 0.05) except bitter taste, which
was found more frequently with TDFC (n = 8) than with latanoprost (n = 0) (P
= 0.01). Amongst patients who
expressed a preference 17 preferred latanoprost and only 2 the TDFC; the most
common reason quoted was the convenience of once a day dosing (N=11).
Conclusion: This study indicates that
the mean 24 hour diurnal intraocular pressure is lower with TDFC compared to
latanoprost in POAG and OHT patients, but most patients prefer latanoprost due
to the convenience of once a day dosing.