Fixed combination of dorzolamide / timolol eye drops versus fixed combination of brinzolamide / timolol eye drops in the treatment of primary open angle glaucoma and ocular hypertension

Abstract

Background: Glaucoma is a worldwide major blinding eye disease. Medical treatment aims at reduction of intraocular pressure (IOP) to prevent further damage to the optic nerve. Dorzolamide 2.0% + timolol 0.5% (D / T - FC) (Cosopt®) and brinzolamide 1.0% + timolol 0.5% (B / T - FC) (Azarga®) are both types of commercially available fixed dose combination eye drops that are used to treat primary open angle glaucoma (POAG) and ocular hypertension (OHT). Dorzolamide and brinzolamide are topical carbonic anhydrase inhibitors (CAIs) fixed combined with timolol a beta-adrenoceptor blocker. CAIs and beta blockers reduce IOP through inhibiting the production of aqueous humor by the ciliary epithelium.Aim: The aim of this prospective clinical therapeutic study was to compare the efficacy and side effects of both combinations in POAG and OHT.Patients & methods: 50 cases of POAG / OHT were enrolled in this study. The patients were randomly assigned to 2 groups with 25 patients in each group. Group 1 received D / T - FC eye drops twice daily while group 2 received B / T - FC eye drops twice daily. Baseline IOP was measured and recorded and then followed up at regular intervals of 2 weeks for one month then monthly for 6 months and then the percentage of reduction was determined. The side effects questioned and reported by the patients were recorded.Results: Both groups had a statistically significant reduction in IOP from baseline (P=0.0001). In the first group IOP reduction ranged from 7.0 to 12.0 mmHg (21.9 – 37.5 %) while in group 2 IOP reduction ranged from 6.5 to 11.0 mm Hg (20.7 – 37.9 %). No significant difference existed between the 2 groups (P=0.6075). Group 2 reported less adverse effects than group 1 (P=0.0412).Conclusion: Both combinations were equally effective in reducing IOP in glaucoma and OHT patients, however B / T - FC was more tolerated.