Towards streamlined product information: reporting of transporter-mediated drug interactions.

Purpose: The purpose of this study is to investigate the reporting of risks associated with transporter-mediated drug-drug interactions (DDIs) in medicinal product information and to identify suitable wording for future standardisation of summaries of product characteristics (SmPCs).

Methods: The SmPCs of medicinal products approved in the European Union from 2012 to 2023 were screened for warnings on Organic Anion Transporting Polypeptide 1B1 and 1B3 (OATP1B1 and OATP1B3), and Breast Cancer Resistance Protein (BCRP). An in-house search engine for product information was used. Warnings were categorised into different DDI scenarios based on the SmPC texts.

Results: A total of 192 out of 859 approved medicinal products had SmPC text pertaining to OATP1B1, 1B3 and/or BCRP. The majority of products had text for all three transporters Most texts were located in SmPC Sect. 5.2, followed by Sect. 4.5. Numerous interaction-texts either concluded that the interaction lacked clinical relevance or lacked information on the clinical relevance of the finding. The highest number of SmPC texts indicating a clinically relevant interaction with outlined clinical consequences was found for BCRP. The article also presents SmPC texts for each DDI scenario, which the authors consider as examples of explicit wordings with actionable recommendations.

Conclusion: A potential for improvement of SmPC text for transporter-mediated DDI was identified: Warnings without clinical relevance could be omitted, and some warnings with clinical relevance could be updated to provide actionable recommendations to the prescribers. A selection of unambiguous texts was identified as starting point to generate standard texts.