alendronate, Fosamax

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GENERIC NAME: alendronate

BRAND NAME: Fosamax

DRUG CLASS AND MECHANISM: Alendronate is in a class of medications called bisphosphonates. The bisphosphonate class includes etidronate (Didronel), ibandronate (Boniva), pamidronate (Aredia), risedronate (Actonel), and tiludronate (Skelid). Bisphosphonates are used for treating osteoporosis (reduced density of bone that leads to fractures) and bone pain from diseases such as metastatic breast cancer, multiple myeloma, and Paget's disease. Bone is in a constant state of remodeling. New bone is laid down by cells called osteoblasts while old bone is removed by cells called osteoclasts. Bisphosphonates strengthen bone by inhibiting bone removal (resorption) by osteoclasts. After menopause, there is an increased rate of bone loss leading to osteoporosis, and alendronate has been shown to increase bone density and decrease fractures of bones. The FDA approved alendronate in September 1995.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 5, 10, 35, 40, 70 mg. Solution: 70 mg

STORAGE: Tablets and solution should be stored at room temperature, 15-30 C (59-86 F) and not frozen.

PRESCRIBED FOR: Alendronate is used for treating osteoporosis in men and postmenopausal women. It also is used for Paget's disease of bone and osteoporosis caused by steroid treatment. Non-FDA approved (off-label) uses include vitamin D overdose and osteoporosis caused by spinal injury.

DOSING: The recommended dose for treatment of osteoporosis is 5-10 mg daily or 35-70 mg weekly. Paget's disease is treated with 40 mg once daily for six months.

Since food, other medications, and vitamins can interfere with the absorption of alendronate, they should be taken at least 30 minutes before alendronate. In order to avoid chemical irritation of the esophagus (the swallowing tube that connects the mouth with the stomach), alendronate should be taken with a full glass of plain water immediately upon arising in the morning and never chewed or sucked. It should be avoided by patients with abnormalities of the esophagus which delay esophageal emptying, such as scarring (stricture) or poor motility (achalasia). Patients should also not lie down for 30 minutes after swallowing the tablets. Those patients who are unable to remain upright for at least 30 minutes after taking alendronate should not take it.

DRUG INTERACTIONS: Calcium supplements and antacids reduce the absorption of alendronate. Therefore, alendronate should be taken at least 30 minutes before calcium and antacids.

Intravenous ranitidine (Zantac) increases blood levels of alendronate. The importance of this reaction is unknown.

The risk of stomach and intestinal side effects may increase when alendronate is combined with aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs).

PREGNANCY: Alendronate has not been studied in pregnant women.

NURSING MOTHERS: It is not known whether alendronate is secreted in breast milk.

SIDE EFFECTS: The most common side effect of alendronate is stomach pain. It also may cause nausea, vomiting, bloating, constipation, diarrhea, gas, black stool (due to intestinal bleeding), change in taste perception, and muscle or joint pain. Alendronate may irritate the esophagus, causing ulcers and bleeding. This occurs more often when patients do not drink enough water with alendronate, wait 30 minutes before lying down, or take alendronate before the first meal of the day. Rarely, patients may experience jaw problems (osteonecrosis of the jaw) associated with delayed healing and infection after tooth extraction.

Bone, joint, and muscle pain also can occur as can femoral fractures.

Reference: FDA Prescribing Information


Last Editorial Review: 7/13/2010




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