Risedronic acid (INN) or risedronate sodium (USAN) is a bisphosphonate used to strengthen bone, treat or prevent osteoporosis, and treat Paget's disease of bone. It is produced and marketed by Warner Chilcott, Sanofi-Aventis, and in Japan by Takeda under the trade names Actonel, Atelvia, and Benet. It is also available in a preparation that includes a calcium carbonate supplement, as Actonel with Calcium.