Bisphosphonates, a class of drugs that includes zoledronic acid, are the most commonly used treatment for osteoporosis. They work by slowing the body's natural reabsorption of bone.
But there has been one enduring problem with bisphosphonates: patients don't take the drugs as they should.
"The big concern has been in patient compliance," Brandt confirmed. "The monthly pills run into problems where women start to forget. It's also a pain to take these drugs. You have to sit upright and there's a risk of acid reflux, esophageal damage."
Women also have to take the pills with a full glass of water while fasting.
According to background information in the paper, most women appear to be taking less than 80 percent of their prescribed pills by 12 months.
Previous research had shown that one annual injection of zoledronic acid improved bone density for at least one year in postmenopausal women with osteoporosis.
The current study looks at how well annual injections do three years out.
Almost 4,000 postmenopausal women were randomly assigned to receive a single 15-minute infusion of zoledronic acid or a placebo at baseline, and then 12 months and 24 months later. Participants were followed out to the 36-month point.
Treatment with zoledronic acid reduced the risk of vertebral
fractures by 70 percent (3.3 percent of women in the treatment arm
and 10.9 percent of women in the placebo arm suffered such
fractures) over three years, the team reported. It also reduced the
risk of
Meanwhile, nonvertebral fractures, clinical fractures and clinical vertebral fractures were reduced by 25 percent, 33 percent and 77 percent, respectively.
Women in the treatment arm also experienced significant
improvement in bone mineral density and bone
There was a slight downside to the injections: women in the
zoledronic acid group experienced more incidents of an irregular
heart rhythm called
More information
There's more on osteoporosis at the National Osteoporosis Foundation.
