Comparing diurnal and nocturnal effects of brinzolamide and timolol on intraocular pressure in patients receiving latanoprost monotherapy.

PURPOSE To compare the diurnal and nocturnal effects of brinzolamide and timolol on intraocular pressure (IOP) in patients already receiving monotherapy with latanoprost. DESIGN Prospective, open-label, and crossover clinical trial. PARTICIPANTS Twenty-six patients with glaucoma or ocular hypertension (ages, 44-79 years) who were receiving treatment with 0.005% latanoprost once every evening. METHODS Baseline data of 24-hour IOP were collected in a sleep laboratory while patients were receiving latanoprost monotherapy. Measurements were taken every 2 hours in the sitting and supine positions during the 16-hour diurnal/wake period and in a supine position during the 8-hour nocturnal/sleep period. Patients were randomly assigned to receive an add-on treatment with either 1% brinzolamide 3 times per day or 0.5% timolol gel forming solution once every morning for 8 weeks, and then crossed over to receive the other add-on treatment. At the end of each add-on treatment period, 24-hour IOP data were collected. MAIN OUTCOME MEASURES Diurnal and nocturnal IOP means were compared among the baseline, the brinzolamide add-on treatment, and the timolol add-on treatment. RESULTS During the diurnal period, the mean IOP under brinzolamide or timolol add-on treatment was significantly lower than the baseline IOP in both the sitting and supine positions. There was no statistical difference between the 2 add-on treatments. During the nocturnal period, the supine IOP under brinzolamide add-on treatment was significantly lower than both the baseline and the timolol add-on treatment. There was no difference in nocturnal IOP between the timolol add-on treatment and the baseline. CONCLUSIONS In patients already receiving the latanoprost monotherapy, adding brinzolamide or timolol significantly reduced IOP during the diurnal period. However, only the brinzolamide add-on treatment had an IOP-lowering efficacy during the nocturnal period.