The impact of reference pricing and extension of generic substitution on the daily cost of antipsychotic medication in Finland

Objective: To assess the impact of reference pricing and extension of generic substitution on the daily cost of antipsychotic drugs in Finland during the first year after its launch. Furthermore, the additional impact of reference pricing on prior implemented generic substitution is assessed. Methods: A retrospective analysis was performed between 2006 and 2010. A segmented linear regression analysis of interrupted time series was used to estimate changes in the levels and trends in the cost of one day of treatment. Of the study drugs, clozapine belonged to generic substitution already at the start of the study period while olanzapine and quetiapine were included in generic substitution alongside with reference pricing in 2009. Risperidone was included in generic substitution in 2008, before reference pricing. Results: A substantial decrease in the daily cost of all four antipsychotic substances was seen after one year of the implementation of reference pricing and the extension of generic substitution. The impact ranged from -29.9% to -66.3%, and it was most substantial on the daily cost of olanzapine. Also in the daily cost of risperidone a substantial decrease of -43.3% was observed. However, most of these savings, -32.6%, were generated by generic substitution which had been adopted prior. Conclusions: Reference pricing and the extension of generic substitution produced substantial savings on antipsychotic medication costs during the first year after its launch, but the intensity of the impact differed between active substances. Furthermore, our results suggest that the additional cost savings from reference pricing after prior implemented generic substitution, are comparatively low.