TREATMENT OF OSTEOPOROSIS AND PREVENTION OF NEW FRACTURES: ROLE OF INTRAVENOUSLY ADMINISTERED BISPHOSPHONATES

Objective: To evaluate the usefulness of intravenously administered bisphosphonates for improving absorption, tolerability, adherence, and outcomes in the treatment and prevention of osteoporosis. Methods: Data published from 1996 to 2009 relevant to the treatment of osteoporosis, with emphasis on bisphosphonates, fracture risk, adherence to therapy, frequency of dosing, intravenous treatment, tolerability, cost-effectiveness, and quality of life, were reviewed. Results: Although bisphosphonates are currently the standard of care for treatment of postmenopausal osteoporosis and osteoporosis in men, oral formulations are associated with poor absorption and potential irritation of the upper gastrointestinal tract. These issues necessitate complicated and restrictive dosing regimens, which in turn lead to poor compliance and persistence. Intravenous formulations such as 3 mg of ibandronate given quarterly and 5 mg of zoledronic acid administered once yearly avoid problems relating to absorption and tolerability by bypassing the gastrointestinal tract. Intravenously administered ibandronate is presumed (by virtue of similar or superior improvements in bone mineral density) to have antifracture efficacy similar to that of orally administered ibandronate given daily, which has been shown to produce significant reductions in vertebral fractures during a 3-year period in comparison with placebo. Zoledronic acid, 5 mg once yearly, has been shown to produce a significant reduction in the risk of morphometric vertebral fractures, clinical vertebral fractures, hip fractures, and nonvertebral fractures versus placebo during a 3-year interval in patients with postmenopausal osteoporosis and also to yield a significantly decreased risk for new clinical fractures versus placebo in patients with recent low-trauma hip fracture. Both agents have favorable safety and tolerability profiles. Couclusion: Intravenously administered bisphosphonates have the potential to increase compliance and persistence with therapy in patients with osteoporosis and to improve patient outcomes. (Endocr Pract. 2009;15:483-493)