Blood Pressure Rx May Not Pose Cancer Threat

Breast cancer risk tied to calcium channel blockers may be smaller than previously thought

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) A blood pressure medication once considered a threat to women's health may not be as bad as researchers thought.

Calcium channel blockers have been linked to increased odds of developing breast cancer. A new study found that the risk of getting breast cancer when using these medications may be smaller than previously thought.

Calcium channel blockers are widely used to treat hypertension (high blood pressure). Last year, the Fred Hutchinson Cancer Research Center in Seattle published a study that said breast cancer risk more than doubled for women who took these heart medications.

Jeffery L. Anderson, MD, a cardiologist and researcher at the Intermountain Medical Center Heart Institute in Salt Lake City, UT, and colleagues wrote the study.

These researchers reviewed medical records on more than 3,700 women from two groups at the Intermountain center. One group of 2,612 consisted of general patients. Another group of 1,106 patients was undergoing coronary angiography. This is a procedure that uses dye and special X-rays to view the insides of coronary arteries to look for heart disease.

The women were all ages 50 to 70 at the start of the study and had no history of breast cancer.

In each of the two groups, Dr. Anderson and colleagues compared women who were prescribed calcium channel blockers to similar women who weren't prescribed the medications.

After five years or less of follow-up, Dr. Anderson and team observed that women in the general patient group who were taking calcium channel blockers were 1.6 times more likely than those who were not taking them to develop breast cancer. On the other hand, patients in the angiography group who were taking channel blockers had a 50 percent reduction in their risk for breast cancer.

Because of these contrasting results, the study authors concluded that it was unlikely that the medication caused the changes in breast cancer risk.

“Given the important role of calcium channel blockers in clinical medicine, further studies are warranted, including randomized trials to assess calcium channel blocker safety with respect to breast cancer risk,” Dr. Anderson and team concluded.

Calcium channel blockers work by blocking calcium from moving into heart cells and blood vessel walls. This widens blood vessels and makes it easier for the heart to pump — which can reduce blood pressure. A few common calcium channel blockers are amlodipine (brand name Norvasc), felodipine (Plendil) and isradipine (DynaCirc).

This study was presented Nov. 19 at the American Heart Association Scientific Sessions 2014 in Chicago. Research presented at conferences may not have been peer-reviewed.

The authors disclosed no funding sources or conflicts of interest.

Review Date: 
November 20, 2014
Last Updated:
November 22, 2014