Bisphosphonates currently are the preferred therapy for treating osteoporosis. Treatment with potent bisphosphonates such as alendronate or risedronate decreases biochemical markers of bone turnover and increases bone mineral density. These changes are associated with significant reductions in vertebral and nonvertebral fracture risk. Clinical trial data with up to 10 years of followup shows these agents are effective and well tolerated for long-term periods. Daily administration is effective and generally well tolerated. However, once weekly doses are more convenient, which may enhance long-term compliance and lead to more successful outcomes. The pharmacokinetics and mechanism of action predict the short-term and long-term skeletal effects and safety profile of once-weekly doses of bisphosphonates are similar to daily doses. These predictions are supported by authors of trials of up to 2 years who report once-weekly doses are therapeutically equivalent to daily doses in terms of BMD and biochemical markers of bone remodeling. Once-weekly bisphosphonate doses have safety and tolerability profiles as good as daily doses and are comparable with the placebo.
Level of evidence: Therapeutic study, Level V (expert opinion). See the Guidelines for Authors for a complete description of the levels of evidence.