BackgroundMandatory generic substitution (GS) was introduced in Finland on 1 April 2003. The aim of this study was to explore and compare the impacts of GS on the activities of pharmaceutical companies representing mainly original or generic pharmaceutical products in Finland. The self-reported impact of GS from pharmaceutical companies' perspective was explored with a focus on the number of employees, the range of sales packages on the market, the marketing activities, the research and development of new pharmaceutical products and storage of pharmaceuticals.MethodsA cross-sectional postal survey was conducted among pharmaceutical companies with an office in Finland and substitutable medicines in the Finnish pharmaceutical market one year (2004) and five years (2008) after the introduction of GS. Completed questionnaires were returned by 16 original and 7 generic product companies in 2004 (response rate 56%, n = 41) and by 16 original and 6 generic product companies in 2008 (response rate 56%, n = 39). Descriptive statistical analyses were performed.ResultsThe number of employees (2004: n = 6/16, 2008: n = 7/16) and the amount of prescription medicine marketing (2004: n = 7/16, 2008: n = 8/16) decreased in many of the original product companies after the introduction of GS. GS resulted in problems related to the storage of pharmaceuticals in the original product companies shortly after GS was introduced (p = 0.032 between 2004 and 2008). In the generic product companies, the prescription medicine representatives' visits to pharmacies increased at the beginning of GS (p = 0.021 between 2004 and 2008). In addition, GS caused problems with the storage of pharmaceuticals one year and five years after the reform (2004: n = 4/7, 2008: n = 3/6). The differences between original and generic product companies regarding the impacts of GS were not, however, statistically significant. GS did not affect on the range of sales packages on the market or the research activities of the majority of companies.ConclusionsThe study suggests that GS has had impacts on the activities of pharmaceutical companies in Finland. There were also some differences, although not statistically significant, between the surveyed original and generic product companies regarding the self-reported impacts of GS. More investigations are needed in this field.