Polypharmacy in older oncology patients and the need for an interdisciplinary approach to side‐effect management

Summary Background and objective:  Older oncology patients with multiple comorbidities are at risk for adverse drug events associated with polypharmacy and drug–drug interactions due to patients’ altered pharmacokinetic/pharmacodynamic status and the narrow therapeutic windows associated with anti-neoplastic agents. This study addresses the issue of polypharmacy and potential drug–drug interactions in outpatients in a community setting in the USA, and the prescribing behaviour of oncologists after being made aware of potential drug–drug interactions. Methods:  We performed a retrospective cohort study in patients with multiple comorbidities exposed to chemotherapy to profile the potential for adverse drug reactions and to define physicians' responses to risks arising from drug interactions. The medical records of 100 patients aged ≥70 years receiving chemotherapeutic agents at a community-based, university-affiliated medical practice were randomly selected and reviewed. Drug class usage was quantified, and potential drug–drug interactions were assessed and categorized. Treating oncologists were encouraged to modify their prescriptions on the basis of potential interactive drug evaluation reports. Physicians’ responses were catalogued. Results and Discussion:  The mean age of the study population was 78 years (range, 70–90 years). Patients had an average of three comorbid conditions. Each patient received an average of 9·1 medications. Cardiovascular drugs were the most common medications that patients used to treat chronic conditions. Carboplatin and paclitaxel were the most frequently used chemotherapeutic agents. Inspite of the potential for drug–drug interactions, physicians made no adjustments to prescriptions. Conclusion:  Given that polypharmacy and the chronic use of multiple drugs are a reality for older patients with cancer and polymorbidities, outcome data need to be generated and motivations/incentives provided for physicians to optimize safe and effective supportive oncologic therapeutics.