PURPOSE: To compare drop volume and treatment cost of generic 0.5% timolol maleate preparations. METHODS: The drop volume of Timoptol® 0.5% (Merck Sharp & Dohme) and its generic preparations (Allergan-Lok, Cristália and Falcon) were determined. Five bottles of each medication were purchased at local drugstores. Using a precision scale, ten drops and one mililiter of each bottle were weighed. Drop volume was calculated by the relation between volume and weight. Duration, in days, of each bottle and annual cost were calculated considering a daily use of 4 drops and maximum price to consumers published May, 2003. RESULTS: Statistically significant differences were observed between drop volumes (p<0.0001%). Allergan-Lok timolol maleate had the largest drop (35.1 µl) and the smallest was Falcon timolol maleate (27.3 µl). Timoptol® drop volume was 27.9 µl. Annual treatment costs were R$ 68.87 for Timoptol, R$ 72.76 for Allergan-Lok timolol maleate, R$ 50.00 for Cristalia timolol maleate and R$ 43.11 for Falcon timolol maleate (p<0.0001). Allergan-Lok timolol maleate was statiscally more expensive than the others and it was 68.8% more expensive than the cheapest. CONCLUSION: There are differences in drop volume among generic medications for glaucoma which are related to their annual cost. Drop volume should be considered in the analysis of quality of generic preparations.
Glaucoma; Glaucoma; Health care costs; Drug costs; Ophthalmic solutions; Drug quality; Socioeconomic factors
