Nationwide prevalence of potential drug-drug interactions associated with non-anticancer agents in patients on oral anticancer agents in South Korea.

purposeWe analyzed the prevalence and severity of potential drug-drug interactions (PDDIs) in Korean patients receiving oral anticancer agents (OAAs) during two different periods.

methodsA cross-sectional study was conducted using the national insurance reimbursement database. The subjects were adult outpatients diagnosed with cancer and prescribed OAAs at least once in 2010 or 2014. PDDIs were identified using a database and the PDDI severity was categorized as category X (contraindications) or D (consideration of therapy modification). The associated factors for the occurrence of PDDIs were also analyzed.

resultsAmong the 118,258 patients prescribed OAAs in 2014, approximately 59% were middle-aged, and approximately half were diagnosed with breast cancer. The number of comorbidities increased over time, and majority were diagnosed with gastrointestinal disorders, hyperlipidemia, and psychonervous disorders. The PDDIs due to protein kinase inhibitors (PKIs) with gastrointestinal/metabolic and neurological drugs increased 3.1- and 4.9-fold, respectively, over the 5 years, and 24.0% of the PDDIs fell into category X. Tamoxifen, the most commonly prescribed OAAs, caused the PDDIs with antidepressants through QTc prolongation or pharmacokinetic interaction. The PKIs prescription, cancer type like breast or hematologic cancer, and number of comorbidities or co-prescribing drugs were independently associated with the occurrence of PDDIs.

conclusionsThe risk of PDDIs in patients receiving OAAs increases, particularly with the concomitant use of PKIs with gastrointestinal or psychiatric drugs and endocrine agents with antidepressants. Considering the potential risk of chronic concomitant use of these drug classes in outpatients, healthcare professionals should be made aware of the potential interactions.