Ophthalmic medication price variation across the United States: Anti-inflammatory medications

BACKGROUND: Cost-related nonadherence to medication can impact ophthalmic treatment outcomes. We aimed to determine whether medication prices vary between US cities and between different types of pharmacies within one city. METHODS: We conducted a phone survey of eight nationwide and five independent pharmacies in five cities across the United States: Boston, Massachusetts; Charlotte, North Carolina; Denver, Colorado; Detroit, Michigan; and Seattle, Washington. A researcher called each pharmacy asking for price without insurance for four common anti-inflammatory ophthalmic medications: prednisolone acetate, prednisolone sodium phosphate, difluprednate (Durezol™), and loteprednol etabonate (Lotemax™). RESULTS: Prednisolone sodium phosphate price could only be obtained by a small subset of pharmacies (45.2%) and was excluded from additional analysis; however, preliminary data demonstrated lower cost of prednisolone sodium phosphate over prednisolone acetate. Three-way analysis of variance revealed no interaction between pharmacy type (chain versus independent), city, and drug (F = 0.40, p = 0.92). A significant interaction was identified between pharmacy type and drug (F = 5.0, p = 0.008), but not city and pharmacy type (F = 0.66, p = 0.62) or city and drug (F = 0.27, p = 0.97). Average drug prices were lower at independent pharmacies compared with chain pharmacies for difluprednate (US$211.36 versus US$216.85, F = 1.09, p = 0.297) and significantly lower for loteprednol etabonate (US$255.49 versus US$274.86, F = 14.7, p < 0.001). Prednisolone acetate was cheaper at chain pharmacies, but not statistically significantly cheaper (US$48.82 versus US$51.61, F = 0.34, p = 0.559). CONCLUSIONS: Medication prices do not differ significantly between US cities. High variation of drug prices within the same city demonstrates how comparison shopping can provide cost savings for patients and may reduce cost-related nonadherence.