Definition: A bisphosphonate is a drug class used to treat and prevent osteoporosis and to treat Paget's disease of bone. Examples with current US labels are alendronate (Fosamax), risedronate (Actonel) and zoledronic acid (Reclast). Their labels share warnings on low calcium, jaw bone death and unusual thigh fractures.
| Product | Form on the label | Approved uses (short form) |
|---|---|---|
| Fosamax (alendronate) | Tablet, 70 mg once weekly | Postmenopausal and male osteoporosis, steroid-induced osteoporosis, Paget's disease |
| Actonel (risedronate) | Tablet | Postmenopausal and male osteoporosis, steroid-induced osteoporosis, Paget's disease |
| Reclast (zoledronic acid) | Infusion into a vein | Postmenopausal and male osteoporosis, steroid-induced osteoporosis, Paget's disease |
Prolia (denosumab) treats the same conditions but is not a bisphosphonate. Its label calls it a RANK ligand inhibitor.
The Fosamax label lists esophagus irritation, low blood calcium, severe bone, joint or muscle pain, osteonecrosis of the jaw and unusual thigh fractures. Reclast adds kidney warnings. Low calcium is corrected before starting. The Fosamax label says the severe pain can start from one day to several months after the first dose, and most people improved after stopping. The jaw and thigh warnings also appear on the Prolia label, so they are not unique to bisphosphonates.
The Fosamax, Actonel and Reclast labels say the best length of use has not been set. The Fosamax label says people at low fracture risk may be considered for stopping after 3 to 5 years. Weekly tablets and yearly infusions are easy to lose track of, so a log with the last date matters more than for a daily pill.
Read more on Dose Track: Fosamax side effects · Actonel side effects · Reclast side effects · Prolia vs Forteo