Objective: From the viewpoint of drug cost reduction, many generic drugs have appeared in the eye drops market.  Although the price of eye drops is defined on a per bottle (or per mL) basis, the difference in the total number of drops per bottle between the original drug and its generic drug may alter the drug cost reduction effect greatly.  Moreover, the difference in the total number of drops per bottle may also affect the number of pharmacy visits made by a patient in one year.
Methods: The total number of drops per bottle of an original drug and a generic drug was computed, and the influence of the number of drops on the drug cost reduction effect, including drug cost, was evaluated.
Results: Distinct differences in the volume per drop and the total number of drops per bottle were observed between the original drug and its generic drug, and those differences were found to clearly influence the drug cost reduction effect.  Moreover, in a survey of patients who shifted to generic eye drops, there were some patients who returned to the original eye drops because they could not apply the generic eye drops with ease or their eyes started to smart after using the generic eye drops.
Conclusion: This study revealed the need to take into consideration patient’s ease of use and the drug cost reduction effect, in the selection of eye drops.