A newly published study finds that first-time users of a class of drugs to treat osteoporosis may be at an increased risk of serious inflammatory eye disease. Bisphosphonates such as Fosamax and Actonel, which are taken orally, are two of the most commonly prescribed drugs in that class.

Published in the April edition of the Canadian Medical Association Journal (CMAJ), Canadian researchers from the University of British Columbia found among 11,000 first-time users, there were 29 incidents per 10,000 person-years (the number of years the drug is taken) of the eye inflammation, anterior uveitis, and 63 per 10,000 person years for scleritis, another inflammatory eye disease. That finding was compared with 20 and 36 respectively for non-users. The results are considered statistically significant.

Uveitis is a swelling of the middle layer of the eye and scleritis is an inflammation of the white outer wall of the eye or sclera.

Oral bisphosphonates include Fosamax, Actonel, Boniva, and Didronel, among others. As we’ve reported here before, long-time use of these drugs has been associated with atypical femur fractures, osteonecrosis of the jaw, irregular heartbeat, musculoskeletal pain, and colon and esophageal cancer.

The osteoporosis drug Reclast, given once a year, should not be used in patients who suffer from renal impairment, according to the U.S. Food and Drug Administration (FDA). That new warning is now on the Reclast label.

No doubt this new study will raise the question whether too many women and men are being prescribed these drugs which interfere with the natural process of bone breakdown and reabsorbtion.

In some cases, prescriptions for bisphosphonates are written when there is only a slight thinning of the bone. The FDA has issued guidelines that bisphosphonate drugs should be prescribed for those with the highest risk of bone fractures.

About 10 million Americans have osteoporosis, with eight million of them women who suffer from post-menopausal osteoporosis, a thinning of the bone which degrades the integrity of the skeletal system leading to fragility and an increased risk of fracture. These drugs are very popular with 150 million prescriptions dispensed in the U.S. between 2005 and 2009.

The inflammatory eye conditions are potentially reversible if identified early, however the labels on osteoporosis drugs do not mention eye inflammation. Patients and their doctors need to be familiar with the symptoms so they can seek immediate and early intervention from an ophthalmologist.