Prevalence and Significance of Potential Pharmacokinetic Drug-Drug Interactions Among Patients with Lung Cancer: Implications for Clinical Trials

Background The overall prevalence of potential drug-drug interactions (DDIs) among patients with lung cancer is unknown. Objective The objective of this study was to determine the prevalence of potential DDIs and major DDIs among individuals newly diagnosed with lung cancer in a national cohort. Patients and Methods We performed a retrospective cross-sectional study of adult patients in the United States Veterans' Affairs (VA) medical system diagnosed with lung cancer between 2003 and 2016. The primary endpoint was the prevalence of prescriptions for medications associated with any potential DDIs during the 3 months leading up to and including the date of lung cancer diagnosis. The secondary endpoint was the prevalence of prescriptions associated with major DDIs during the same time period. Results Overall, 280,068 patients were included in the study; 55.9% of patients were prescribed medications associated with potential DDIs, while 5.3% received prescriptions for medications associated with major DDIs. Among the 20 most commonly prescribed drugs associated with potential DDIs, only two were associated with major DDIs. Conclusion Medications with potential DDIs are prescribed to the majority of patients with lung cancer; however, only about 5% of patients are prescribed medications with major DDIs that might be prohibited in certain clinical trials.