[Objective evaluation of generic-specific drug information].

Growth in the use of generic drugs remains flat in Japan, and one of the reasons cited is information availability. We previously showed that the amount of information available on generic drugs differs greatly from one pharmaceutical industry to another, though, on average, it is inferior to that for original, brand name drugs. This report looks at information on individual generic drug products, rather than the active ingredients contained therein. In May 2004, we studied ingredients sold by at least 20 pharmaceutical industries. Here, for the same, particular ingredient, we evaluate current availability of generic-specific information (as of August 2005), as well as change over time. On the basis of ingredient, the amount of information provided for generic drugs is 31.1+/-17.5-57.3+/-11.7% that for the corresponding original drugs (Mean+/-S.D.), but in the company-by-company comparison, a large dispersion of 16.6+/-5.0-69.4+/-11.9% (Mean +/-S.D.) is observed. In terms of information content, generic drugs provided less than 50% as much information on "drug interactions", "clinical efficacy", and "outline of side effects", as that for original drugs. The difference between generic and original drugs was smaller in comparisons focusing on information specific to generics than on those including all drug information. Our study also revealed that, over time, some pharmaceutical industries have added to the amount of information provided. When information is a deciding factor, the quantity available at the current time is not the only relevant aspect; it is best to select a pharmaceutical industry that is proactive about supplementing information post-release.