Fixed-combination glaucoma medication reduces IOP more than each medication alone

Am J Ophthalmol. 2011;151(1):93-99.

Patients with glaucoma or ocular hypertension who received fixed-combination brimonidine-timolol had a better chance of achieving a low mean IOP with less IOP fluctuation than patients who received brimonidine or timolol monotherapy, according to a study.

A total of 1,159 patients were evaluated, of whom 385 received Combigan (brimonidine tartrate 0.2%, timolol maleate 0.5% ophthalmic solution, Allergan) twice a day, 382 received Alphagan (brimonidine tartrate 0.2%, Allergan) three times a day and 392 received timolol maleate 0.5% (Allergen) twice a day in each eye for 12 months.

The post hoc analysis included data from two identical, randomized, phase 3, double-masked, multicenter trials.

After 12 months, 43% of patients in the combination group had mean diurnal IOP less than 18 mm Hg and a daily IOP fluctuation less than or equal to 2 mm Hg, compared with 18.9% of patients in the brimonidine group and 33.5% of patients in the timolol group, according to the study.

Researchers defined fluctuation as the standard deviation of IOP measurements, and follow-up of diurnal IOP measurements was conducted at 2 weeks and 6 weeks, as well as every 3 months for 1 year.

At the hours of 8 a.m., 10 a.m., 3 p.m. and 5 p.m., researchers found that the combination group had a significantly higher percentage of patients (41% at 8 a.m.) with mean IOP less than 18 mm Hg and an intervisit IOP fluctuation less than or equal to 2 mm Hg; 11.3% of patients in the brimonidine group and 23.7% of patients in the timolol group had those readings at 8 a.m. (P < .001), the study said.

"As IOP fluctuation may have an important effect on [visual field] progression and patient outcomes, we recommend that analyses of data from additional comparative studies be performed to evaluate IOP fluctuation as well as mean IOP levels with available IOP-lowering medications," the study authors said.