No clear association between oral bisphosphonate use and atrial fibrillation has been confirmed. Most clinical and observational studies published to date on this issue have not been sufficiently powered to detect rare or uncommon adverse events. One adequately powered observational study, which studied hospital admissions of women diagnosed with atrial fibrillation and atrial flutter, found there was no increased risk for users of oral etidronate and alendronate.1
Medsafe will continue to closely monitor the safety of oral bisphosphonates as new information becomes available. In the meantime, prescribers are advised not alter their prescribing patterns for oral bisphosphonates.
Recently published evidence does however support an association between infusions of zoledronic acid and serious atrial fibrillation.2 The risk was only 0.6-0.7% higher than placebo, with around 1.3% of patients treated with zoledronic acid diagnosed with serious atrial fibrillation. Medsafe advises prescribers the risk to benefit ratio for zoledronic acid remains highly favourable. The data sheets for zoledronic acid infusions available in New Zealand already contain information regarding this risk. Medsafe is currently reviewing clinical data for pamidronic acid in respect of atrial fibrillation and will update prescribers if any increased risk is identified.
1. Sorenson HT, Christensen S, Mehnert F, Pederson L, Chapurlat RD, Cummings SR & Baron JA (2008) Use of bisphosphonates among women and risk of atrial fibrillation and fl utter: population based case-control study British Medical Journal 336:813-6.
2. Black DM, Delmas PD, Easell R, Reid IR, Boonen S, Cauley JA, Cosman F, Lakatos P, Leung PC, Man Z, Mautalen C, Mesenbrink P, Hu H, Sellmeyer D, Eriksen EF & Cummings SR (2007) Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis New England Journal of Medicine 356(18):1809-22.