Background: Package inserts should convey important information and promote correct, safe and effective use of medicines. The purpose of this study was to investigate possible differences in the information on package inserts between a selection of generic medicines on the substitution list of the Norwegian Medicines Agency.
Material and method: We based our investigation on the 25 most commonly used drugs in Norway. Eight of these drugs were excluded since they were not listed or did not have generic equivalents on the substitution list. For the remaining 17 drugs we procured the package inserts for a total of 71 medicines and compared the texts. Differences which we judged to be a possible source of worry or confusion for the patient were included.
Results: There was only one drug for which the package inserts for all the medicines were almost identical. For three other drugs there were consistently few differences. For the remaining 13 drugs (76%) there were cosiderable differences between the package inserts. There were generally fewest differences in the information on indications for use and most in the information on side effects. In many cases medical expressions without further explanation and unclear and vague words and expressions were used.
Conclusion: There are significant differences in the information in package inserts for generic medicines. This may lead to confusion, uncertainty and poorer patient compliance. The treating doctor should inform patients who are prescribed a generic medicine that the information on the package insert may vary, but that the medicines nevertheless have equal therapeutic value.