Blood-Pressure Drug Norvasc Linked to Breast Cancer Risk

August 6, 2013 — A study published by JAMA Internal Medicine has found that certain medications used to reduce blood-pressure may increase a woman’s risk of breast cancer.

Using drugs in the “calcium-channel blocker” class for 10 or more years was associated with a 2.5-fold increased risk of breast cancer. Other types of blood-pressure medications were not associated with an increased risk of breast cancer.

Researchers evaluated data on women in the Seattle-Puget Sound metropolitan area who were between 55 and 74 years old. Researchers compared data on 880 women with invasive ductal breast cancer, 1027 with invasive lobular breast cancer, and 856 women with no cancer to serve as controls.

The researchers warned:

“Long-term current use of calcium-channel blockers in particular are associated with breast cancer risk. Additional research is needed to confirm this finding and to evaluate potential underlying biological mechanisms.”

This is the first study to link breast cancer to calcium-channel blocking medications. However, the study is concerning for many people, because blood-pressure drugs are the most commonly prescribed medicines in the United States. Of the 678 million prescriptions for the drugs, about 98 million prescriptions were written for calcium-channel blockers. One of the most popular calcium channel blockers is Norvasc, a generic drug that is manufactured by Pfizer.