LIFELONG HEALTH Osteoporosis drug has problematic side effects

— For millions of women, and more recently men, the use of medications to treat osteoporosis has led to fewer fractures and less disability with advancing age. The most commonly employed medications are bisphosphonates, which have been shown to be highly effective in building bone mass and strength. Unfortunately, bisphosphonates have been associated with some very serious side effects.

To understand how bisphosphonates work, we must first understand normal bone metabolism. Adult bones are not unlike a large tree - tough, sturdy and seemingly inactive. But look past the exterior and you will find that bones are vibrant, living, ever-changing parts of the human body. Throughout life, bone is continually being remodeled, broken down by cells called osteoclasts while simultaneously being rebuiltby cells called osteoblasts.

This combined production and destruction determines the strength and resilience of our bones. If there is either decreased production or increased destruction of bone,osteoporosis or conditions like it will develop. In the most common form of osteoporosis, found in post-menopausal women and in men over the age of 70, the major cause is decreased production caused by declines in hormones, inadequate calcium or vitamin D, and inadequate exercise.

Osteoporosis can be diagnosed clinically by the development of a fracture or through screening with a bone density, or DEXA, scan. When bone loss is minimal, further decrease can be prevented by diet and exercise. But if severe, treatment is warranted and bisphosphonates are the drugs of choice. These drugs build bone strength by inhibiting osteoclasts that cause the breakdown of bone, thus altering the delicate balanceof bone destruction and production. With increased production comes greater bone strength.

Recently thousands of patients have spontaneously stopped taking bisphosphonates due to reports of scary side effects. The most frequent side effect is indigestion, heartburn and damage to the esophagus. To prevent this from happening, the drug must be taken on an empty stomach with a full glass of water and the patient should not lie down or eat for 30 to 60 minutes. More rarely, abdominal pain and diarrhea have been reported. The drug occasionally cannot be tolerated because of fatigue or muscle and joint pain.

Perhaps the most serious side effect of bisphosphonates is a condition called osteonecrosis of the jaw. Here, death of bone in the jaw can occur after surgery, leading to pain, swelling, infection and exposure of bone. The condition is quite common in patients who receive frequent injections of bisphosphonates to treat cancer that has spread to the bone. However, the condition occurs less frequentlyafter therapy for osteoporosis (1 per 100,000 patients). Regardless, the risk makes many dentists wary of performing major procedures on patients who have taken bisphosphonates.

These side effects occur because the bone built after treatment with any bisphosphonate is not totally normal. For this reason, experts recommend ceasing the drug for a year after bisphosphonates have been taken for five to seven years.

In a study just released by the New England Journal of Medicine, researchers indicate that there is hope for treating or preventing osteonecrosis of the jaw. Teripeptide (Forteo), a drug used to treat osteoporosis, aided bone recovery in patients undergoing surgery for periodontal disease. Furthermore, researchers reported complete healing in a patient with severe osteonecrosis of the jaw after treatment withForteo, which is given as a subcutaneous injection daily for two years. In contrast to the bisphosphonates, Forteo stimulates bone production rather than inhibiting bone destruction.

Despite the side effects of bisphosphonates, these medications still remain the treatment of choice for osteoporosis. The cheapest generic form should be used first and intravenous injections should be given only to those unable to tolerate newer therapies. Other medications such as Forteo should only be considered if the bisphosphonates are not tolerated or contraindicated.

A new medication (Prolia) is given as a subcutaneous injection twice a year. While more convenient thanthe daily shots of Forteo, it is a new, untested, expensive treatment with a similar mechanism of action to the bisphosphonates, hence the same side effects.

The long-term suffering and disability caused by osteoporosis is very profound. Despite some adverse effects, treatment with medications, when used appropriately, is well worth it.

Dr. David Lipschitz is the director of The Longevity Center at St. Vincent Infirmary Medical Center. More information is available at:

drdavidhealth.com

High Profile, Pages 45 on 10/31/2010

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