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Fosamax is prescribed to prevent or treat osteoporosis in postmenopausal women. Doctors prescribe it to increase bone mass in men with osteoporosis. It is also used to treat a fairly rare condition, Paget's disease of bone.

Bone is constantly being "remodeled," broken down by osteoclasts and rebuilt by osteoblasts. Under normal conditions, these two types of bone cells should work together.

With aging, the osteoblasts often slow down, and more bone is destroyed ("resorbed") than is constructed. Fosamax slows the osteoclasts so that bone-building osteoblasts can keep up or get ahead.

Side Effects and Interactions

Fosamax may occasionally cause stomach ache, nausea, constipation or diarrhea, flatulence, trouble swallowing, and esophageal ulcer.

Although esophageal ulcers are uncommon, they can be extremely serious. Another rare but dangerous reaction that has been reported is osteonecrosis of the jaw–death of the jaw bone tissue. This has generally been linked to tooth extractions or other invasive dental procedures.

Anyone taking Fosamax who notices difficulty or pain when swallowing, pain behind the breastbone, or new or more intense heartburn should stop Fosamax and contact the physician promptly.

Other side effects such as muscle pain, skin reactions and eye inflammation have also been reported.

Fosamax works best when the patient is getting adequate calcium and vitamin D. These should be taken at least one half-hour after taking Fosamax, to avoid interfering with absorption of the drug.

Aspirin and arthritis pain relievers, both prescription and over-the-counter, can irritate the digestive tract. This may increase the risk of severe esophageal irritation from Fosamax. Antacids should be taken at least 2 hours after Fosamax. They could interfere with absorption if given at the same time.

Check with your doctor and pharmacist to make sure this medicine is safe in combination with any other drugs you take.

Special Precautions

Fosamax can be very irritating to the esophagus. People with any swallowing problems or those who cannot sit or stand for at least 30 minutes should not take Fosamax.

People with ulcers or esophageal disease should avoid Fosamax also.

Fosamax is not recommended for patients with severe kidney disease.

Taking the Medicine

Fosamax is not well absorbed, and must be taken exactly according to instructions.

The pill is to be taken first thing in the morning, right after rising, with a full glass of plain tap water.

Mineral water, coffee, and orange juice may all interfere with drug absorption.

The patient must stay upright, sitting up or standing (not lying down), for at least 30 minutes after taking Fosamax. Only after that half hour has elapsed should she have breakfast, drink coffee or juice, or take other medications.

Best absorption of Fosamax occurs if two hours goes by between taking the pill and eating.

Fosamax may be taken every day or once a week. The same instructions apply to the weekly dose.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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