A single-centre retrospective evaluation of potential drug-drug interactions in breast cancer patients undergoing CDK 4/6 inhibitors chemotherapy.

Introduction: The utilization of CDK4/6 inhibitors has led to compromised survival rates for breast cancer patients. Consequently, certain treatment aspects, involving adherence and drug-to-drug interactions, are gaining prominence. To develop chemotherapy regimens that are both effective and efficient, our main objective was to thoroughly characterize the drug-drug interactions that occur between cyclin-dependent kinase inhibitors and concurrently prescribed medications in hospitalized breast cancer patients.

Methods: In the current retrospective analysis, (January 2017 to January 2023), the baseline characteristics of patients under CDK4/6 chemotherapy were collected by reviewing the patient's medical records. Utilizing drug interactions checker softwares including Micromedex online database system, Drugs.com interaction checker, and UpToDate Lexicomp, the potential for drug-drug interactions was further assessed.

Results: In this retrospective analysis, total of 75 co-medications were prescribed along with palbociclib and ribociclib. Upon analysing all co-prescribed classes of drugs, the potential drug interactions of palbociclib and ribociclib with analgesics, acid-reducing agents, and statins occurred frequently in cancer patients. In the 21-patient cohort, 17 patients (80.95%), were found to be having prevalence of potential drug-drug interactions out of which 41.26% had major pharmacokinetic interactions, 42.85% were moderate ones, while 15.87% were pharmacodynamic interactions.

Conclusion: The retrospective analysis identified the potential risks associated with drug-drug interactions of cyclin-dependent kinase 4/6 inhibitors. Potentially, the application of drug interaction detectors could facilitate additional implementation of research specially designed for interventions aimed at enhancing patient care.