These Common Meds May Worsen Breast Cancer Treatment Side Effects

If you take medicine to treat heartburn or high blood pressure, you may be at greater risk of severe side effects from breast cancer treatment, new research suggests. Proton pump inhibitors, used to treat heartburn and indigestion, were most strongly linked to severe side effects. The findings were published in Cancer Medicine.  

The study included information from around 23,000 clinical trial participants with early-stage or advanced breast cancer. Most participants were taking anti-HER2 therapies. Other therapies included CDK4/6 inhibitors, hormonal therapy, and chemotherapy. 

The researchers focused on participants who were also taking drugs to treat high blood pressure, high cholesterol, Type 2 diabetes, and/or heartburn. Participants taking proton pump inhibitors had shorter survival than participants not taking proton pump inhibitors. This group also had a 36% higher risk of severe side effects from treatment. Severe side effects are events that are not life-threatening but require people to be hospitalized. 

High blood pressure meds, including beta-blockers, ACE inhibitors, and calcium-channel blockers, were also linked to more severe side effects. Cholesterol drugs including statins and metformin didn’t impact side effects or survival. 

By understanding how common drugs interact with breast cancer treatments, doctors can better guide treatment decisions and improve patient care. 

The research “underlies how important it is for doctors to regularly review patient medications because people are living longer and managing multiple health issues,” said study author Natansh Modi, PhD, a lecturer in pharmacology at the University of South Australia, in a statement. If you’re taking these medications during cancer treatment, talk with your doctors about the risks and benefits.