Harvard Women's Health Watch

Osteoporosis drugs: Which one is right for you?

There's no one-size-fits-all answer. Understanding your options begins with knowing what's available.

Throughout our lives, our bones undergo constant renovation. In a process called bone turnover, cells called osteoclasts break down and remove old bone, and then cells called osteoblasts lay down new bone. After menopause, the rate of bone removal speeds up, and bone formation doesn't always keep pace. The net result can be bone loss and ultimately the weakened, brittle bones of osteoporosis.

Even if you've been diagnosed with osteoporosis, a fracture isn't inevitable. Many drugs available today can slow the rate of bone loss—and can rebuild bone strength.

Your doctor will determine whether you have osteoporosis by measuring your bone density—usually at the hip and spine—using dual energy x-ray absorptiometry (DEXA). The result, expressed as a number called a T-score, compares your bone density with that of a healthy 30-year-old woman.

The doctor will likely recommend medicine if you have

  • a T-score of –2.5 or lower—the definition of osteoporosis

  • a history of hip or vertebral (spinal) fracture caused by a fall while standing (in contrast to a fall from a height)

  • a T-score between –1.0 and –2.5 (called osteopenia) and a high risk of hip or osteoporosis-related fracture in the next 10 years according to a fracture risk calculator.

Osteoporosis treatment: Where to start

To slow bone breakdown, many doctors first turn to one particular class of drugs. "If someone has a very low T-score, we'll typically start with the bisphosphonates," says Dr. David Slovik, associate professor of medicine at Harvard Medical School and endocrinologist at Massachusetts General Hospital.

There are several bisphosphonates to choose from:

  • pills, such as alendronate (Fosamax), ibandronate (Boniva), or risedronate (Actonel, Atelvia), taken daily, weekly, or monthly

  • injections of ibandronate (Boniva), given once every three months

  • intravenous infusion of zoledronic acid (Reclast), given once a year.

"I like starting with alendronate because it's been around the longest, it has shown a good therapeutic response, and it comes in a generic version, which can save patients money," Dr. Slovik says.

Your doctor will also consider where your bone loss is centered. Alendronate, risedronate, and ibandronate have all been shown effective for reducing spine fractures. For women with a history of hip or nonspinal fractures, alendronate and risedronate are better options than ibandronate.

If you have gastrointestinal problems like reflux, or if you can't sit or stand upright for the full 30 to 60 minutes required after taking an oral bisphosphonate, then your doctor may put you on an injection or infusion of these drugs, which works about as well as the oral versions.

You might have read about risks associated with bisphosphonate drugs—particularly fractures of the thighbone (femur) and osteonecrosis (bone death) in the jaw. Though these concerns are real, they are more common in people taking intravenous bisphosphonates to treat cancer that has spread to the bones, or in women who are on long-term, high-dose bisphosphonates.

Doctors acknowledge that the risk of these side effects also increases with long-term use of bisphosphonates, so most women take these drugs for about five years. The good news is that the bone-protective benefits continue even after you stop taking bisphosphonates.

Other drug options

For postmenopausal women who aren't starting with a bisphosphonate, or those who've already been on one for five years, here are a few other options.

Raloxifene (Evista), a selective estrogen receptor modulator (SERM), is perhaps best known for its role in breast cancer prevention and treatment, but it serves double duty in treating osteoporosis, too. It works by binding with estrogen receptors around the body to produce estrogen-like effects, one of which is to decrease bone turnover. "For people with osteoporosis of the spine, raloxifene reduces the risk of vertebral fractures," Dr. Slovik says. The main side effects are hot flashes, muscle pain, and an increased risk of blood clots in the leg (deep-vein thrombosis).

Teriparatide (Forteo) is a synthetic version of parathyroid hormone that increases bone density and strength. It can reduce the risk of fractures significantly in the spine and other bones. "If someone has very low bone density and vertebral fractures, I often consider treatment with teriparatide," Dr. Slovik says. Doctors usually limit teriparatide treatment to two years, because it hasn't been tested for longer than that. After two years, your doctor may switch you to a bisphosphonate to help you maintain bone density. Women on teriparatide need to give themselves a daily injection.

Denosumab (Prolia) is given as a twice-yearly injection. It prevents bone-dissolving osteoclast cells from forming. Denosumab may be an option if a woman cannot tolerate bisphosphonates.

Calcitonin (Miacalcin, Fortical) has been around since the 1980s, making it the oldest osteoporosis drug. It's a hormone that binds to osteoclasts to prevent bone loss. When taken as a daily nasal spray or by injection, calcitonin can reduce spinal fractures, but it hasn't been shown effective for preventing other types of fractures and is not a first-line treatment for most women.

A number of other osteoporosis drugs are in development, including a new monoclonal antibody (romosozumab) and drugs that block sclerostin, a protein that inhibits bone formation. However, Dr. Slovik doesn't think we're going to see any of these new drugs approved within the next year. For now, the best ways to strengthen bone are with the existing osteoporosis drugs.

Osteoporosis drugs compared




How it works

Risks/side effects


  • alendronate (Fosamax, Binosto)

  • daily or weekly tablet or weekly effervescent tablet that you dissolve in water

  • strengthens bones by slowing the rate at which osteoclasts remove bone

  • gastrointestinal problems, such as trouble swallowing, inflammation of the esophagus, and ulcers

  • osteonecrosis (death of bone tissue) in the jaw (rare)

  • ibandronate (Boniva)

  • monthly tablet or injection every three months

  • strengthens bones by slowing the rate at which osteoclasts remove bone

  • fracture of the thighbone (femur) with more than five years of use (rare)

  • risedronate (Actonel, Atelvia)

  • daily, weekly, or monthly tablet

  • strengthens bones by slowing the rate at which osteoclasts remove bone

  • irritation at the injection site

  • flu-like symptoms—headache, muscle aches, fever

  • fracture of the thighbone (rare)

  • osteonecrosis of the jaw (rare)

  • zoledronic acid (Reclast)

  • yearly intravenous infusion

  • strengthens bones by slowing the rate at which osteoclasts remove bone

  • allergic reactions

  • small increase in cancer risk


  • calcitonin (Miacalcin, Fortical)

  • daily nasal spray or injection

  • inhibits bone removal by osteoclasts, and increases the rate of new bone formation by osteoblasts

allergic reactions

  • small increase in cancer risk

parathyroid hormone

  • teriparatide (Forteo)

  • daily injection

  • increases the number of bone-forming osteoblasts

  • leg cramps

  • nausea

  • dizziness

monoclonal antibody

  • denosumab (Prolia)

  • injection given by a health care provider twice a year

  • prevents the development of bone-removing osteoclasts

  • low blood calcium

  • skin infections and rash

  • osteonecrosis of the jaw (rare)

  • fracture of the thighbone (rare)