A new enteric-coated delayed-release formulation of risedronate (Atelvia – Warner Chilcott) has been approved by the FDA for treatment of postmenopausal osteoporosis. Unlike immediate-release risedronate (Actonel) and all other oral bisphosphonates, which must be taken after an overnight fast and at least 30 minutes before eating breakfast, the new formulation is taken immediately after breakfast with at least 4 ounces of water. Then the patient must remain upright for at least 30 minutes.

CLINICAL TRIAL — Approval of Atelvia was based on a 52-week non-inferiority study in more than 900 postmenopausal women comparing the new 35-mg delayed-release tablet taken once each week to the original immediate-release 5-mg tablet taken daily at least 30 minutes before breakfast. (FDA approval of risedronate was based on studies with the 5-mg tablet taken once daily; now Actonel is usually taken, like Atelvia, as a 35-mg tablet once a week.) Increases in bone mineral density at the lumbar spine and other locations and changes in markers of bone turnover were similar in both groups. Diarrhea and abdominal pain occurred more frequently with the new formulation once weekly after breakfast than with risedronate 5 mg daily (8.8% vs. 4.9% and 5.2% vs. 2.9%, respectively).1

DOSAGE AND COST — Atelvia is available as a 35-mg tablet taken once each week. A month’s supply of the new formulation (four 35-mg tablets) costs $119.99, which is similar to the cost of Actonel once a week ($126.47).2 Alendronate (Fosamax, and others) is currently the only bisphosphonate available generically that is FDA-approved for treatment of osteoporosis; a month’s supply is available at some discount pharmacies for $9.

CONCLUSION — Taking the new enteric-coated delayed-release formulation of risedronate (Atelvia) after breakfast presumably would be more convenient than taking immediate-release risedronate 30 minutes before breakfast, but it may cause more diarrhea. Generic alendronate costs much less than either one.