A Pharmacoeconomic Analysis to Determine the Relative Cost-effectiveness of Timolol 0.5%, Brinzolamide 1% and Brimonidine 0.2% Eye Drops in Treatment of Primary Open Angle Glaucoma/Ocular Hypertension

Abstract

Aim: A pharmacoeconomic analysis to determine the relative cost-effectiveness of timolol 0.5%, brinzolamide 1% and brimonidine 0.2% eye drops in treatment of Primary Open Angle Glaucoma (POAG)/ocular hypertension (OHT). Settings and Design: Comparative, open, randomized, parallel group prospective study. Materials and Methods: 60 patients of POAG or ocular hypertension were included in this study. Time period of study was 6 weeks. 60 eyes of 60 patients were included in the study. Patients were divided randomly into 3 groups of 20 each. Patients in group A, B and C received timolol, brinzolamide and brimonidine respectively. One drop of each medication was instilled twice a day at 9 am and 9 pm daily for 6 weeks. IOP was measured on day 0 at 9 am (before administration of drugs) and then at 11 am, to get baseline IOP. IOP was again measured on subsequent visits at 9 am and 11 am. Treatment outcome was number of mm Hg fall in IOP induced by the study drug. The daily cost of each drug was calculated by maximum retail price and the average number of drops per bottle. The cost-effectiveness was then calculated as the cost of drug/mm Hg fall in IOP. Statistics: Paired 't' test was used to analyze the parameters within the group. Independent samples t-test was used to compare the efficacy of drugs with each other. Results: The % reduction of brimonidine, timolol and brinzolamide at end of 6 weeks was 21.43 ± 3.06%, 24.87 ± 2.46% and 18.78 ± 1.73% respectively. Timolol was superior in efficacy to other two drugs. The difference was statistically significant between the efficacy of timolol and brinzolamide (p < 0.001) as well as timolol and brimonidine (p = 0.003). There was no statistical significant difference in the efficacy of brimonidine when compared to brinzolamide (p=0.26). Timolol (5.87 ± 0.83 Rs/mm lowering after 6 weeks) was found to be most cost-effective followed by brimonidine (46.83 ± 7.37) and then brinzolamide (60.49 ± 6.77) in lowering IOP. Conclusion: All three drugs under the present study are useful in the treatment of POAG/OHT, but timolol is a better choice than other two drugs because of greater reduction in IOP and greater cost-effectiveness.