Response of bone mineral density to once-weekly administration of risedronate

To evaluate the changes in bone mineral density (BMD) and the tolerability associated with treatment with risedronate, 30 mg once weekly.

Risedronate, 30 mg, was administered once weekly before breakfast to patients with osteoporosis or osteopenia. All patients were also treated with calcium, 1,500 mg daily, and supplemental vitamin D. Patients receiving treatment with other antiresorptive agents were not excluded. BMD was assessed with dual-energy x-ray absorptiometry (DEXA) at baseline and 1 year.

After a mean of 11.6 +/- 0.4 months, mean BMD had increased at the lumbar spine and total hip, respectively, by 5.7% (P<0.001) and 2.9% (P<0.001) among all patients, by 4.8% (P<0.001) and 2.2% (P<0.04) among 23 treated with risedronate alone, and by 6.7% (P<0.003) and 3.6% (P<0.004) among 21 receiving risedronate and other antiresorptive agents. Linear regression analysis of the relationship between baseline T-score and BMD increment at the lumbar spine and femoral neck showed a statistically significant negative correlation, an indication of an enhanced response to treatment in patients with lower baseline T-scores. Adverse events possibly associated with risedronate therapy were recorded in 3 of the 70 enrolled patients (dyspepsia in 2 and urticaria in 1). Of 44 patients with follow-up DEXA scans, 12 (27%) had not tolerated alendronate (10 mg daily) previously, but they tolerated once-weekly risedronate therapy without difficulty.

A once-weekly 30-mg regimen of risedronate increases BMD when administered alone or with other antiresorptive agents. Few adverse events possibly associated with risedronate therapy were noted.