When older adults with cancer take multiple medications – including ordinary drugs like blood pressure pills, supplements, or antacids – it can result in more toxic chemotherapy side effects and even a need to stop cancer treatment, according to new research at the Wilmot Cancer Institute.

The latest study, published in the journal Cancer, provides a cautionary note to both patients and physicians regarding “polypharmacy”,  a buzzword describing the concurrent use of multiple medications. It’s extremely common, applying to nearly 92% of older adults with cancer.

The study uncovered a significant finding: individuals with one or more major potential drug interactions had a 59% higher likelihood of having to discontinue their cancer treatment earlier than advised. This underscores the critical importance of avoiding potentially harmful drug interactions, as they can significantly impact the effectiveness and duration of cancer treatment. By carefully considering a patient’s medication regimen and potential drug interactions, healthcare providers can help ensure that their patients receive the best possible care and achieve the best possible outcomes.

“It’s possible that polypharmacy affects both the experience and the effectiveness of chemotherapy,” said Erika Ramsdale, MD, a Wilmot oncologist, geriatrics specialist, data scientist, and senior author of the paper.  

Last year, Ramsdale and colleagues published a descriptive study that laid out the scope of the polypharmacy problem and categorized medication issues in a nationwide sample of 718 adults with a mean age of 77 who had stage 3 or 4 cancer and other health conditions. Read more.

According to the first study conducted by researchers, the majority of the patients being treated had at least one other serious health concern, with cardiovascular disease being the most common. Additionally, 70% of the patients were at risk of drug-drug interactions, while 67% were taking at least one drug that was potentially inappropriate for their condition.

Furthermore, the study revealed that 61% of the patients were taking five or more medications prior to beginning chemotherapy, with nearly 15% taking 10 or more medications. These findings highlight the importance of considering a patient’s overall health and medication regimen when designing a chemotherapy treatment plan, in order to minimize the risk of adverse drug reactions and maximise treatment effectiveness.

Both studies suggest that physicians should carefully screen for medication usage and possible drug interactions upon a new patient’s cancer diagnosis.