Risedronate on two consecutive days per month.

Risedronate, an orally administered pyridinal bisphosphonate, is effective in the treatment and prevention of postmenopausal osteoporosis. Efforts to optimize patient adherence and persistence with, and hence the effectiveness of, therapy have led to the development of a 75 mg tablet to be taken on two consecutive days each month (2CDM). After 1 year of treatment, risedronate 75 mg 2CDM was noninferior to risedronate 5 mg once daily in improving lumbar spine bone mineral density (BMD) in an ongoing (2-year) randomized, double-blind, parallel-group, multinational trial in 1229 postmenopausal women with osteoporosis. Mean percentage increases in BMD from baseline at 12 months were 3.4% and 3.6% in the 75 mg 2CDM and 5 mg once-daily groups; the upper limit of the 95% confidence interval for the treatment difference (5 mg once daily - 75 mg 2CDM; -0.19%, 0.62%) did not exceed the predefined noninferiority margin (1.5%). In general, improvements in hip BMD and reductions in bone turnover markers with the 75 mg 2CDM regimen were not significantly different from those with the 5 mg once-daily regimen; there was no significant between-group difference in the incidence of new vertebral fractures at 12 months. The tolerability profile (including the incidence of upper gastrointestinal tract adverse events) of risedronate 75 mg 2CDM in postmenopausal women with osteoporosis was similar to that of risedronate 5 mg once daily.