Ocular hypotensive effect and safety of brinzolamide ophthalmic solution in open angle glaucoma patients.

BACKGROUND AND PURPOSE

Brinzolamide is a new topical carbonic anhydrase inhibitor for intraocular pressure (IOP) control. It has high inhibitory activity against human carbonic anhydrase II, which is the key isoenzyme regulating aqueous humor production. We conducted this study to compare the ocular hypotensive effect and safety of 1% brinzolamide versus that of 0.5% timolol twice daily.

METHODS

In a double-masked design, 50 open angle glaucoma patients who had a baseline IOP between 20 to 30 mm Hg were randomized to receive either 1% brinzolamide ophthalmic solution or 0.5% timolol twice daily. After completing a 2-week pre-study screening period, patients were scheduled to receive 6 weeks of treatment. Visual acuity, IOP, slit-lamp biomicroscopy, corneal thickness, refraction status, blood pressure, heart rate, and treatment-related signs and symptoms were evaluated at follow-up visits. The eye selected for treatment was the one with the higher baseline IOP, or the right eye if the IOPs were the same in both eyes. The fellow eye served as control.

RESULTS

48 patients completed the study, and there were 24 patients in each group. A significant decrease in mean IOP was found after 6 weeks of treatment in both the brinzolamide group (-17.0%) and the timolol group (-19.7%), with no significant between-group difference in the control of IOP. The central corneal thickness of treatment eyes, measured by ultrasound pachometry, had not changed after 6 weeks of brinzolamide treatment. The study medications were generally well tolerated and no serious adverse reactions occurred during the 6-week study period.

CONCLUSION

When used twice a day, topical brinzolamide is as effective as 0.5% timolol in lowering IOP in patients with open angle glaucoma.