The DDDs for the bisphosphonates are based on the treatment of osteoporosis if this is an approved indication.
The DDDs for clodronic acid, pamidronic acid, zoledronic acid, parenteral etidronic acid and parenteral ibandronic acid are based on tumor induced hypercalcemia. The oral DDD for ibandronic acid is based on osteoporosis. Since the duration of the intravenous treatment courses with the bisphosphonates are varying, from 1-5 days, the DDDs for these parenteral formulations are assigned according to the total course dose. The DDDs for the oral formulations, which are mainly used for maintenance therapy, are assigned according to daily dosages.
The DDDs for alendronic acid, risedronic acid, and oral etidronic acid are based on treatment of osteoporosis.
The DDD for tiludronic acid is based on the treatment of Paget's disease.