Osteoporosis drugs may increase stroke risk in cancer patients

New research reveals that cancer patients who are treated with osteoporosis-fighting drugs such as bisphosphonates are at an increased risk for abnormal heart rhythms and stroke. The study appears in the Journal of Clinical Oncology.

The benefits of these drugs for preventing and treating cancer after it has spread to the bone, especially in breast cancer patients, still outweigh their risks as long as patients are monitored closely, according to the study's lead author, Dr James S. Goodwin.

Studies had already linked bisphosphonates to atrial fibrillation and stroke, but in 2008 the U.S. Food and Drug Administration concluded that "healthcare professionals should not alter their prescribing patterns for bisphosphonates."

However, doses of these drugs that are given to treat cancer patients with bone metastasis are typically 10 times higher than those used in patients with osteoporosis. The study findings show that cancer patients taking bisphosphonates were at a 30 percent higher risk of atrial fibrillation - an irregular beating rhythm in the heart's atrial chamber - compared to those who were not given the drugs.

If doctors find that a patient has atrial fibrillation, which they can do by listening to the heart, they can immediately prescribe blood-thinning drugs to prevent a stroke, the researcher said.