ESTES PARK, COLO. — Many bone disease experts are recommending a 1- to 2-year bisphosphonate holiday after 5 years of treatment in response to a recent spate of reports of atypical fractures of the femoral diaphysis.
There are now more than 70 reports of these atypical transverse fractures of the femoral shaft occurring in patients on bisphosphonates for longer than 5 years. Affected individuals have also had severely suppressed bone turnover markers, Dr. Michael T. McDermott said at a conference on internal medicine sponsored by the University of Colorado.
“This tells us that drugs that turn off a major process like bone remodeling may be very valuable for 3-5 years, but we have to ask, are they good for longer periods of time? We don't know the answer yet,” observed Dr. McDermott, professor of medicine and director of diabetes practice at University of Colorado Hospital, Aurora.
These distinctive fractures have been bilateral in two-thirds of cases. There is no associated history of trauma, just spontaneous thigh pain. Radiographically they look like nonhealing stress fractures that have completed through the bone shaft.
“Treatment holidays are not advised for high-risk patients,” he stressed. For such patients—those who have a T-score less than −2.5 and/or previous fractures—options include a switch to an anabolic agent such as teriparatide (Forteo) or to a nonbisphosphonate antiresorptive agent such as raloxifene (Evista), estrogen, or calcitonin. Continuing the bisphosphonate in a high-risk patient also is a reasonable strategy, he said.