Home » Drug Information » FDA Approved Drugs » 1995
Medical Areas: Endocrinology | Musculoskeletal | Obstetrics/Gynecology (Women’s Health) | Family Medicine
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Fosamax (alendronate sodium)
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Approval Status: Approved on September 29, 1995
Treatment Area: Post-menopausal osteoporosis, Paget's disease of bone
Fosamax reduces the activity of the cells that cause bone loss
and helps build healthy bone. It is the first nonhormonal medicine
for women after menopause who have osteoporosis.
The FDA also cleared Fosamax for the treatment of Paget's
disease of bone, a chronic disorder that affects up to 1.3 million
Americans and may result in enlarged and deformed bones in one or
more regions of the skeleton.
The FDA clearance of Fosamax to treat osteoporosis is based on
efficacy data from five clinical trials involving 1,827
postmenopausal women with osteoporosis in 16 countries who were
followed for at least two years.
In clinical trials, Fosamax significantly increased bone mineral
density (closely related to bone strength) at the spine (8.2%), hip
(7.2%), and other sites. While the studies were not designed to
detect fracture risk, further analysis supports that Fosamax
reduced the number of women with new spinal fractures by nearly
half (48%), reduced the total number of new spinal fractures by
63%, and reduced overall height loss by 35%. Women treated with
Fosamax lost an average of 3 mm in height, compared with women on
placebo who lost an average of 4.6 mm in height.
Side effects observed in clinical trials were generally mild.
The most commonly reported drug-related side effects in subjects
taking Fosamax were abdominal and musculoskeletal pain. Less
frequently reported were other digestive disturbances such as
nausea, heartburn, and irritation or pain of the esophagus.
Fosamax is indicated for the treatment of osteoporosis in
postmenopausal women. Osteoporosis is a progressive disease of the
skeleton caused by an imbalance in the body's bone-rebuilding
cycle. Osteoporosis is characterized by low bone mass, which
results in bones that are prone to fracture, or by the presence or
history of an osteoporotic fracture. Bone mass is closely related
to bone strength; the greater the bone mass, the stronger the bones
and the less likely they are to fracture.
Osteoporosis affects more than 25 million Americans, 80 percent
of them women. Each year, osteoporosis causes more than 1.3 million
fractures, including 500,000 spinal fractures, 250,000 hip
fractures, and 240,000 wrist fractures.
Bone is constantly being rebuilt (or remodeled) throughout life
in a process in which old bone tissue is broken down (or resorbed)
by cells called osteoclasts and replaced with new bone tissue by
cells called osteoblasts. In healthy young adults, the overall rate
of remodeling is usually in balance so that the amount of bone lost
is about equal to the amount that is replaced.
However, after menopause, more bone is broken down than is
replaced, causing bone loss to occur and bones to become weaker.
This is due to a drop in the level of estrogen. In the first five
years after menopause, women may lose as much as 25% of their bone
mass. In fact, menopause is the single most important risk factor
for osteoporosis in women.
In patients with Paget's disease of bone, excessive
remodeling causes the bone to be enlarged but fragile, and may
result in bone pain, deformities, fractures and in some cases,
arthritis and neurological complications.
Merck estimates that the retail price for a daily dose of 10 mg
will be between $1.65 and $1.80.