Side Effects of Osteoporosis Drugs

Osteoporosis, meaning porous bone, is a disease marked by weak bones which increases the risk of fractures even from minor falls and injuries. Osteoporosis affects more than 10 million Americans, 8 million of which are women. There are several different types of medications commonly prescribed to treat osteoporosis, unfortunately they do have some side effects.

Bone Remodeling

• Bone is a living tissue; therefore new bone is continually replacing old bone through a process called the bone remodeling cycle. This cycle consists of two distinct parts: the bone resorption, where bone is broken down and removed; and the bone formation, where new bone is formed. In healthy individuals the two parts of the cycle are in balance; however, in osteoporosis there is an imbalance, with more bone broken down than formed. Some medications target the bone-resorption phase and others support the bone-formation phase.

Bisphosphonates

• Bisphosphonates are a class of medications that are taken to slow down the rate of bone loss during bone resorption. Bisphosphanates include many of the most common medications prescribed, including Fosamax, Actonel, Boniva and Reclast. The side effects of these medications include bone, joint and muscle pain, nausea, difficulty swallowing, heartburn, esophagus irritation and gastric ulcer. Rarely a patient may experience uveitis, which is swelling of the eye. There are also rare cases of osteonecrosis (the death of bone cells) in the jaw reported, but most of these were in cases where bisphosphonates were given intravenously,which usually only happens in cases such as cancer treatments.

Other Antiresoptive Medications

• Another medication that works to slow down the loss of bone is calcitonin, sold as the brand names Fortical and Miacalcin. Calcitonin is a naturally occurring hormone that works to regulate calcium. Calcitonin slows down bone loss which helps to increase bone density. Calcitonin medications can be taken either orally or as a nasal spray.
  Common side effects of calcitonin include flushing of the hands and face, increased urination, nausea and skin rash. The nasal spray may also cause headaches, runny nose, nose bleed and back pain.

Hormone Therapy

• Hormones, including estrogen and estrogen with progesterone, have a positive effect on reducing bone loss in post-menopausal women. Hormones, delivered either orally or by skin patch, are especially effective in increasing bone density in the hips and spine. Hormone therapy with estrogen is associated with many side effects including vaginal bleeding, breast tenderness and gallbladder disease. It has also been linked with more serious conditions such as stroke, blood clots and an increased risk of breast cancer. For these reasons, doctors prefer to prescribe non-estrogen medications for the treatment of osteoporosis.

Estrogen Agonist/Antiagonist

• The medication raloxifene, sold as the brand name Evista, is a Selective Estrogen Receptor Modulator (SERM) that acts similar to estrogen, but without the associated side effects. It is effective in reducing bone loss and therefore increasing bone density. The side effects of raloxifene are minimal, including hot flashes, leg cramps and blood clots. It can also cause flu-like symptoms but the advantage is that it has shown to decrease estrogen related breast cancer by 65 percent.

Bone-forming Medications

• The medication teriparatide, brand name Forteo, is the only medication approved for use that rebuilds bone. This medication is prescribed to those who still continue to suffer from osteoporosis symptoms even when taking other medication. It is administered by self-injections. The side effects of teriparatide are dizziness and leg cramps. Although it has shown to increase the blood levels of calcium, there is no evidence that it causes an increased risk of kidney stones. Teriparatide is only prescribed for two years because continued use can increase the risk of osteocarcinoma (bone tumors).