The Answers.com Dictionary describes osteoporosis as:

A disease in which the bones become extremely porous, are subject to fracture, and heal slowly, occurring especially in women following menopause and often leading to curvature of the spine from vertebral collapse.

The Connecticut Center for Health offers several methods of treatment, from lifestyle changes to medication. Fosamax is one such medication. However, the Center for Health warns:

Taking Fosamax or Tums is neither the complete nor the optimal treatment for osteoporosis or osteopenia. A comprehensive treatment program customized to your particular needs is the better approach.

Now, according to an article in the National Review of Medicine:

New research shows that zoledronic acid (Aclasta), a drug used to treat Paget's disease, reduced bone fractures in older women by 70% over three years. The HORIZON (Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly) study, which appears in the May 3 issue of NEJM, suggests that zoledronic acid is as effective as other osteoporosis meds, but the once-yearly dose gives both compliance and bone mineral density a big boost.

However, as with most medicines, this does not come without risks. The National Review reports that an increased risk of atrial fibrillation was observed in some women. Atrial fibrillation is an abnormal heart rhythm which involves the two upper chambers of the heart.