Effect of concomitant use of latanoprost and brinzolamide on 24-hour variation of IOP in normal-tension glaucoma.

PURPOSE: To study the effect of the concomitant use of latanoprost and brinzolamide on the 24-hour variation in the intraocular pressure (IOP) in patients with normal-tension glaucoma (NTG). METHODS: We studied a total of 44 eyes from 22 NTG patients. Mean 24-hour IOP variation was determined after a washout period of > or =4 weeks. Latanoprost monotherapy was continued in both eyes for 8 weeks. Thereafter, patients were randomized to continue latanoprost monotherapy in 1 eye whereas brinzolamide was added as an adjunct to latanoprost therapy in the other eye. Eight weeks after the initiation of brinzolamide treatment, the 24-hour IOP variation was remeasured. IOP was measured in the sitting position 8 times daily using a Goldmann applanation tonometer before and after treatment. RESULTS: The eyes treated with latanoprost monotherapy and those treated with latanoprost and brinzolamide showed a significant decrease in IOP at all time points. Percent reductions in the diurnal mean IOP (mean IOP at 10 AM, 1 PM, and 4 PM) and in nocturnal mean IOP (mean IOP at 10 PM, 1 AM, and 3 AM) were significantly greater in the eyes treated with the combination of latanoprost and brinzolamide than those with latanoprost alone (diurnal mean IOP: latanoprost and brinzolamide=19.8%, latanoprost=14.1%, P<0.001; nocturnal mean IOP: latanoprost and brinzolamide=13.4%, latanoprost=10.0%, P<0.05). CONCLUSIONS: For the treatment of NTG, the combination of latanoprost and brinzolamide demonstrated additive effects in lowering IOP, not only during the day, but also at night.