The newer ocular hypotensive agents available to treat glaucoma and ocular hypertension (OHT) include latanoprost, a prostaglandin F(2alpha) analogue, and the fixed combination of dorzolamide hydrochloride, a carbonic anhydrase inhibitor, and timolol maleate, a beta-blocker.
The aim of this study was to compare the efficacy and tolerability of latanoprost with that of the fixed combination of dorzolamide and timolol over 8 weeks.
This interventional, 8-week, randomized, open-label, parallel-group study was conducted at 18 centers in 6 Latin American countries. Patients with unilateral or bilateral primary open-angle, pigmentary, or exfoliative glaucoma or OHT were randomized to receive latanoprost, 1 drop in the affected eye QD (evening), or fixed-combination dorzolamide/timolol, 1 drop in the affected eye BID (morning and evening). Medications were self-administered, 1 drop per affected eye. At baseline and week 8, intraocular pressure (IOP) was measured 3 times each at 8:30 am, 10:00 am, 2:00 pm, and 5:00 pm and after the water-drinking test, which estimates the IOP peak of diurnal tension curve, performed following the 5:00 pm IOP assessment. The primary efficacy outcome was change in diurnal IOP (the mean of IOP measurements) from baseline to week 8. Adverse effect (AE) data were recorded at each visit.
A total of 229 patients were randomized (latanoprost, n = 112; dorzolamide/timolol, n = 117). Mean baseline diurnal IOP values were similar between the 2 groups. Mean (SD) diurnal IOP reductions at week 8 before the water-drinking test were 6.9 (3.0) mm Hg for the latanoprost group and 6.4 (3.2) mm Hg for the dorzolamide/timolol group. Mean IOP values were similar at all time points except at 5:00 pm, when levels were significantly lower in latanoprost-treated patients (P = 0.025). After the water-drinking test, the increase in IOP values was similar between groups at baseline but lower in latanoprost-treated patients at week 8 (adjusted difference, 1.08 mm Hg; P = 0.012). Fewer patients treated with latanoprost reported ocular or systemic AEs (P = 0.025 and P < 0.001, respectively).
In this study of patients with unilateral or bilateral primary open-angle, pigmentary, or exfoliative glaucoma or OHT IOP reductions generally were similar between treatment groups, except at 5:00 pm, when the mean IOP level was significantly lower in latanoprost-treated patients. Latanoprost was better tolerated than fixed-combination dorzolamide and timolol.