Breast Cancer Risk Greater With Long-Term Use of Calcium-Channel Blockers for Blood PressureAug 6, 2013
Women who take a popular blood pressure medication for more than a decade significantly increase their chances of developing breast cancer.
According to a Bloomberg News report this week, a new study found that women prescribed drugs in the class known as calcium-channel blockers face a 2.5-times greater risk of breast cancer if they take that drug for more than 10 years. The risk is greater among women taking these specific blood pressure drugs than drugs in another class.
Researchers at Translational Research Program at the Fred Hutchinson Cancer Research Center in Seattle believe this is the first study to confirm a link between taking calcium-channel blockers and breast cancer but believe more research is needed and women who take these drugs should not immediately quit the drugs. The study team wants to know now why the link is evident between calcium-channel blocker drugs and breast cancer. This study is published in the journal, JAMA Internal Medicine, according to the Bloomberg report.
The top-selling calcium-channel blocker drug is Norvasc, manufactured by Pfizer Inc. Bloomberg reports that in 2010, there were about 98 million prescriptions filled for Norvasc and other calcium-channel blocker drugs. Calcium-channel blocker drugs work by relaxing blood vessels. They also prevent calcium from entering cells. Other options available for anyone in need of blood pressure regulation include diuretic drugs or those in a class known as beta-blockers.
This initial study examined health histories of nearly 2,000 women with breast cancer and nearly an additional thousand who didn't have breast cancer. Their drug histories were analyzed to come up with the data for the study, Bloomberg reports. The heightened risk of breast cancer was only noted among women who took calcium-channel blocker drugs like Norvasc. Researchers said they weren't sure why that risk was evident only among one class of drugs used to treat blood pressure.
The study, inconclusive on several fronts, only noted the heightened risk among older women participating in the study. All participants in the study were over the age of 55. An Abstract of the study available through the JAMA website shows that the specific calcium-channel blocker used did not have an impact on the elevated risk of breast cancer.
Also, researchers noted that too many women in the study had stopped taking calcium-channel blocker drugs at the time they were analyzed, Bloomberg notes in its report.