OBJECTIVE: Prostamides have recently been introduced for the treatment of glaucoma patients. We wanted to understand and evaluate the effectiveness and cost for new anti-glaucoma medications and study the potential cost-savings role that newer therapies may play in the prevention of glaucoma progression to blindness. In this study, we compared estimated effectiveness and costs, from a payer perspective, of a prostamide and a representative from another fairly new category of anti-glaucoma medications, the combination products. METHODS: A pharmacoeconomic model was constructed based on a three-month randomized controlled efficacy trial comparing Lumigan (bimatoprost 0.03%, a new synthetic prostamide) and Cosopt (a fixed combination product of timolol 0.5% and dorzolamide 2.0%). The clinical trial evaluated the percent of patients achieving various target intraocular pressures (IOPs) throughout the day and the cost of treatment to achieve target was calculated based on the estimated effectiveness from the trial. Total expected annual treatment costs included direct costs of both medications and ophthalmology visits. RESULTS: With bimatoprost, 30% of patients (N = 27) reached and maintained a target IOP of < 17 mm Hg for all measurements throughout the day vs. 17% with the combination product (N=15; p < .05). Average expected annual treatment costs, incorporating the costs of treatment success and failure (requiring additional medications and office visits) were EURO 485 vs. EURO 471 for bimatoprost vs. the combination product, respectively. Cost-effectiveness, calculated as medication cost/expected effectiveness based on patients achieving a target IOP at three months of < 17 mm Hg, was EURO 139 vs. EURO 190 for bimatoprost vs. the combination product, respectively. CONCLUSION: Annual expected treatment costs for prostamides and combination products are similar. However, when cost-effectiveness is considered, due to a greater percentage of glaucoma patients achieving ideal target treatment goals with prostamides, prostamides appear to be more cost-effective than combination products.