There are many medications available for the prevention and treatment of osteoporosis. They improve bone mineral density and have been proven to significantly decrease the risk of fractures. The currently available medications are listed below.

Estrogen in the form of traditional hormone replacement therapy has been proven to improve bone density and reduce the risk of fractures of the hip, spine (vertebral) and wrist. It acts by preventing bone resorption through inhibition of osteoclast formation and function. It also prolongs the life span of the osteoblast.

The concerns of hormone therapy are the small association with the diagnosis of breast cancer and the increased risk of thromboembolic events such as blood clots and stroke. At this point there are other effective medications and therefore estrogen would not be recommended as a first line therapy for osteoporosis.

Studies have documented increased bone loss after discontinuation of estrogen. All women who elect to stop hormone therapy should be assessed for the risk of osteoporosis and treated appropriately.

Biphosphonates include a group of medications that act by destroying the osteoclasts. The result is a significant decrease in bone turnover and bone loss. These medications have been proven thus far to be the most effective in fracture reduction. Studies have documented a 40-50% reduction in vertebral fractures and a 20-40% reduction in nonvertebral fractures including hip.

They include Fosamax (Alendronate), Actonel (Risedronate), and Boniva (Ibandronate). Therapies include daily, weekly and monthly regimens.

Side effects can include gastrointestinal problems such as ulcers and abdominal pain. In addition there is a rare occurrence of necrosis of the bone of the jaw. Discontinuation of this medication can result in increased bone turnover and a decrease in bone density.

Selective estrogen receptor modulators (SERMS) exert estrogen like effects on selective tissue while avoiding some of the undesired effects of estrogen. Evista (Raloxifene) is the SERM that has been studied in osteoporosis. It acts by decreasing bone turnover and has been proven to decrease the risk of vertebral fractures by 34-50%.

The side effects include hot flashes and an increased risk of thromboembolic events such as blood clots. The potential benefit is that it has demonstrated effectiveness in breast cancer prevention and may soon be approved for this use.

Raloxifene probably should be used in osteoporosis prevention and would not be the first choice for the treatment of osteoporosis, except maybe of the spine.

Calcitonin inhibits osteoclast activity thereby preventing bone resorption. It was available only in an injectable form however the nasal spray Fortical has recently come on the market. In those with a diagnosis of osteoporosis it has been shown to decrease the risk of spine fractures by 33%. It is generally well tolerated.

Parathyroid hormone is available as a daily subcutaneous injection called Forteo (Teriparatide). The exact mechanism of action is unclear however it appears to stimulate bone formation even on inactive bone surfaces. The activity of both the osteoclast and osteoblast are increased with an overall net effect of increased bone formation. Studies have demonstrated an increase in bone density of both the hip and spine. They also report a 69% reduction in spinal fractures and a 53% reduction in nonvertebral fractures.

Adverse effects include nausea, headaches, and an increase in serum calcium levels. There was also an observed increase in the incidence of osteosarcoma in animal studies. For this reason it is only recommended for cases of severe osteoporosis and those at high risk of fracture. This medication should not be used for longer than 2 years. The benefits in terms of improved bone density will disappear when the medication is stopped so use of another agent is advised after discontinuation.

There are many effective medications available for the prevention and treatment of osteoporosis. In cases of severe disease there is also the option of combination treatment with 2 agents that have different mechanisms of action. No medication is completely free of risk or side effects. You can work closely with your health care provider to choose the one that is right for you.