No Link Between Bisphosphonates and Atrial Fibrillation, FDA Says

Yael Waknine


November 13, 2008

November 13, 2008 — A review of clinical trial data has revealed no clear association between overall bisphosphonate exposure and the rate of serious or nonserious atrial fibrillation (AF), the US Food and Drug Administration (FDA) announced today. In addition, increasing the dose or duration of therapy was not linked to an increased risk for AF.

Healthcare professionals should therefore not alter their prescribing patterns for bisphosphonates, and patients should not stop taking their medication, according to an alert issued by MedWatch, the FDA's safety information and adverse event reporting program.

Currently marketed bisphosphonates include alendronate (Fosamax and Fosamax Plus D, Merck and Co, Inc), etidronate (Didronel, Procter & Gamble Pharmaceuticals, Inc), ibandronate (Boniva, Roche Pharmaceuticals, Inc), pamidronate (Aredia, Novartis Pharmaceuticals Corp), risedronate (Actonel and Actonel with Calcium, Procter & Gamble), tiludronate (Skelid, sanofi-aventis US, Inc), and zoledronic acid (Reclast and Zometa, Novartis).

The FDA review, which began in October 2007, was prompted by publications in May 2007 that described increased rates of serious AF in 2 studies of osteoporotic women aged 65 to 89 years receiving alendronate or zoledronic acid therapy. It encompassed drug company–submitted data from placebo-controlled clinical trials (n = 38,045) of alendronate, ibandronate, risedronate, or zoledronic acid given for 6 months to 3 years.

Although 1 large study of zoledronic acid showed a statistically significant increase in AF risk, the incidence of AF was rare overall, with most studies reporting 2 or fewer cases (absolute difference vs placebo, 0% – 0.3%).

Because these findings differ from those in the literature and other epidemiologic studies, the FDA will continue to monitor postmarketing reports of AF in patients receiving bisphosphonate therapy; the feasibility of conducting additional epidemiologic studies is also being explored.

Bisphosphonates are a class of drugs used primarily to increase bone mass and decrease the risk for fracture in patients with osteoporosis.

Adverse events related to use of alendronate, etidronate, ibandronate, pamidronate, risedronate, tiludronate, and zoledronic acid should be reported to the FDA's MedWatch reporting program by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at, or by mail to 5600 Fishers Lane, Rockville, MD 20852-9787.


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