US regulators have issued a health alert over the possibility of certain osteoporosis treatments causing “severe and sometimes incapacitating” bone, joint and muscle pain in patients suffering from the disease.

The US Food and Drug Administration says that it is looking at the severe musculoskeletal pain that has been reported with the use of bisphosphonates, including Novartis’ Reclast/Zometa (zoledronic acid) and Aredia (pamidronate), Merck & Co’s Fosamax (alendronate), Procter & Gamble's Didronel (etidronate), Roche and GlaxoSmithKline's Boniva (ibandronate), Sanofi-Aventis and P&G’s Actonel (risedronate), plus Sanofi’s Skelid (tiludronate).

The agency says that although severe musculoskeletal pain is included in the prescribing information for all of the aforementioned drugs, its association with bisphosphonates “may be overlooked by healthcare professionals, delaying diagnosis, prolonging pain and/or impairment, and necessitating the use of analgesics”. Some patients have reported complete relief of symptoms after discontinuing the bisphosphonate, said the FDA, whereas others have reported “slow or incomplete resolution”.

The regulator concluded by saying that the risk factors for, and incidence of, severe musculoskeletal pain associated with bisphosphonates are unknown but doctors should consider whether their use might be responsible for such pain and they should consider “temporary or permanent discontinuation of the drug”.

This is the second time in the last few months that the FDA has made declarations about bisphosphonates. In October, the agency issued an early communication about an ongoing safety review of all bisphosphonates which was initiated after the May 3, 2007 issue of The New England Journal of Medicine suggested that two different studies in older women with osteoporosis of Reclast and Fosamax could increase the risk of atrial fibrillation. The review is likely to continue for another six months.