Reasons for patients’ generic drug switching at the pharmacy counter: a pilot study

Background: Drug switching describes switching between drug products with the same active substance. Drug switching occurs commonly in the Netherlands and mostly between generic drug products, however, the specific reasons for switching are incompletely understood. Methods: To document reasons for drug switches between products with the same active substance in the Netherlands. Results: In total, 207 drug switches were recorded. Most drug switches were caused by nationwide drug shortages (32%, n = 66) and the Dutch price-based tender system (23%, n = 47). Other reasons for switching included deals between pharmacists and wholesalers (12%, n = 25), distribution issues at wholesalers (11%, n = 22), and a financially favourable margin for pharmacists (11%, n = 21). Conclusion: This study indicates that drug shortages and the Dutch price-based tender system are likely to be major causes of drug switches in the Netherlands. However, other reasons, such as drug product distribution issues and local economic incentives, were also identified.