Reasons for allowing and refusing generic substitution and factors determining the choice of an interchangeable prescription medicine: a survey among pharmacy customers in Finland.

Background: Generic substitution (GS) was introduced in Finland in 2003 and supplemented with a reference price system (RPS) in 2009. Patients play a vital role in the acceptance of GS and the use of less expensive generic medicines. The objective of this study was to explore Finnish pharmacy customers' experience with allowing and refusing GS. Specific aims were to investigate the reasons for (1) allowing and (2) refusing GS and (3) to determine the prescription medicine-related factors influencing the customer's choice of an interchangeable prescription medicine.

Methods: A questionnaire survey was conducted in February 2018. Questionnaires were handed out from 18 community pharmacies across Finland to customers ≥18 years who purchased for themselves a prescription medicine included in the RPS. A descriptive approach was used in the analysis using frequencies, the Chi-square test and Fisher's exact test.

Results: The final study material consisted of 1043 questionnaires (response rate 40.0%). Of the customers, 47.9% had both allowed and refused GS, 41.2% had only allowed GS and 6.0% had only refused GS. Customers had allowed GS because they wanted to lower their medicine expenses (75.5%), or because the prescribed medicine (30.8%) or medicine they had used before (27.4%) was unavailable at the pharmacy. The main reasons for refusing GS were an insignificant price difference between interchangeable medicines (63.3%) and satisfaction with the medicine used before (60.2%). The main factors influencing customers' choice of an interchangeable prescription medicine were price (81.1%), familiarity (38.4%) and availability (32.8%). Customers who had allowed GS chose the medicine based on price. Customers who had only refused GS appreciated familiarity more than the price of the medicine.

Conclusions: GS is a common practice in Finnish community pharmacies. The price of the medicine was the most important factor affecting customers' decision to allow or refuse GS and the choice of an interchangeable prescription medicine. Thus, customers should receive information about medicine prices at the pharmacy in order to help them make their decision. However, individual needs should also be taken into account in counselling because customers regard several factors as important in their choice of an interchangeable medicine.