By the way, doctor: Should I take an intravenous drug for osteoporosis?
Q. I've been taking a Fosamax pill once a week for two years for osteoporosis. I heard that there is an intravenous drug for osteoporosis that's taken just once a year. Should I consider switching to it?
A. The report that a yearly infusion of zoledronic acid reduces fracture risk has many postmenopausal women asking the same question. Zoledronic acid is a bisphosphonate. Like other medications in this class, such as the oral drugs alendronate (Fosamax) and risedronate (Actonel), it reduces bone resorption (breakdown). It's approved for treating bone damage and high blood levels of calcium in cancer patients. In 2002, researchers found that a single infusion increased bone mineral density (BMD) and reduced bone turnover for a full year afterwards, spurring interest in zoledronic acid as a treatment for osteoporosis.
In May 2007, researchers at the University of California in San Francisco reported on the results of a randomized trial involving nearly 8,000 women with osteoporosis, ages 65 to 89. Half received zoledronic acid once a year, and half received a placebo. After three years, the women taking zoledronic acid had higher BMDs at the hip and spine and suffered less height loss. About 3% had spine fractures, compared with nearly 11% in the placebo group — a 70% reduction in risk. There were also fewer hip fractures in this group.