Objective: To evaluate the efficacy and tolerability of brimonidine purite 0.1% in comparison to brinzolamide 1% when used as adjunctive therapy to latanoprost 0.005% in patients with glaucoma or ocular hypertension.

Methods: Randomized, single-center, investigator-masked, parallel-group clinical study. Patients with IOP >or= 18 mmHg while on once-daily latanoprost were randomized to adjunctive treatment with brimonidine purite TID (n = 20) or brinzolamide TID (n = 20) for 3 months. Intraocular pressure (IOP) was measured at 8 a.m., 10 a.m., and 4 p.m. at latanoprost-treated baseline and after 1 and 3 months of latanoprost and adjunctive therapy. A patient questionnaire was administered to evaluate the tolerability of eye drop instillation.

Results: Baseline mean diurnal IOP (+/- standard deviation, mmHg) on latanoprost was comparable between groups (brimonidine purite: 19.6 +/- 2.94; brinzolamide: 19.8 +/- 3.25; p = 0.846). Mean diurnal IOP at Month 3 was 16.3 +/- 2.63 mmHg with brimonidine purite and 17.8 +/- 2.19 mmHg with brinzolamide (p = 0.028). Adjunctive use of brimonidine purite provided greater IOP lowering than brinzolamide at 10 a.m. (p < 0.001) and 4 p.m. (p = 0.050) and equivalent IOP lowering to brinzolamide at 8 a.m. (p = 0.716). Blurred vision at Month 1 and bitter taste at Months 1 and 3 were more common upon instillation of brinzolamide eye drops.

Conclusions: Brimonidine purite 0.1% provided significantly lower IOP compared with brinzolamide 1% when used as adjunctive therapy to latanoprost. Both adjunctive therapies were well tolerated. Limitations of this study include the use of a single site and the sample size. Additional studies are needed to further evaluate these drugs as adjunctive therapy to prostaglandin analogs.