Osteoporosis. Efficacy and safety of a bisphosphonate dosed once weekly.

Trabecular and cortical bone is continuously being remodeled at microscopic loci called basic multicellular units (BMU). Estrogen deficiency in menopause contributes to an increase in osteoclastic resorption and/or a decrease in osteoblastic formation, which leads to microscopic bone loss at the BMUs. Drug treatments for osteoporosis are intended to inhibit bone resorption, reduce the rate of bone turnover, and increase bone mass. The bisphosphonate alendronate was recently approved for once-a-week dosing for the prevention and treatment of postmenopausal osteoporosis. A 70-mg, once-a-week dose of alendronate has been shown to be therapeutically equivalent to the standard daily 10-mg dose. Tolerability and safety of weekly dosing appear to be similar to daily dosing.