What are two drugs commonly prescribed for osteoporosis?

October 10, 2025 •

5 min read

In the U.S., an estimated 10.2 million people aged 50 and over had osteoporosis in 2010. So, what are two drugs commonly prescribed for osteoporosis? The most common are bisphosphonates, such as Alendronate, and another option is Denosumab.

Quick Summary

The most common first-line medications for osteoporosis are bisphosphonates, which include drugs like Alendronate. Another widely used option is Denosumab, a monoclonal antibody. Both work to reduce bone loss and lower fracture risk.

Key Points

Two Common Drugs: Bisphosphonates (like Alendronate) and Denosumab are two common, effective drug classes for osteoporosis.
Bisphosphonates (Alendronate): These are often the first-line treatment, working by slowing down the cells that break down bone. They are typically taken as a weekly or daily pill.
Denosumab (Prolia): This is a monoclonal antibody given as an injection every six months that blocks the formation of bone-resorbing cells.
Different Mechanisms: Alendronate slows existing bone-resorbing cells, while Denosumab prevents them from forming in the first place.
Administration Varies: Alendronate requires strict dosing rules (empty stomach, remaining upright), while Denosumab is a simple injection given by a healthcare provider.
Stopping Treatment is Risky: Discontinuing Denosumab can lead to rapid bone loss and an increased fracture risk, requiring a transition to another medication.
Lifestyle is Key: Medications are most effective when combined with sufficient calcium and vitamin D intake, weight-bearing exercise, and fall prevention strategies.

Understanding Osteoporosis and Bone Density

Osteoporosis is a common bone disease characterized by a loss of bone density and strength, making bones porous, weak, and more susceptible to fractures. Throughout life, bones undergo a constant process of breaking down old bone and rebuilding new bone. As people age, particularly after menopause for women, this balance shifts, and bone breakdown outpates bone formation, leading to weaker bones. In 2017–2018, the age-adjusted prevalence of osteoporosis among U.S. adults aged 50 and over was 12.6%, affecting 19.6% of women and 4.4% of men.

Diagnosing osteoporosis often involves a bone mineral density (BMD) test, such as a dual-energy X-ray absorptiometry (DXA) scan, which measures the mineral content of your bones. The results are often given as a T-score. A T-score of -2.5 or lower indicates osteoporosis. Treatment focuses on slowing bone loss and reducing the risk of fractures through lifestyle changes and medication.

First-Line Treatment: Bisphosphonates

Bisphosphonates are the most widely prescribed class of drugs for treating osteoporosis and are often the first choice for treatment. They work as antiresorptive agents, meaning they slow down the rate at which bone is broken down. By inhibiting the action of osteoclasts—the cells responsible for bone resorption—bisphosphonates help preserve bone mass and increase bone density, which in turn lowers the risk of fractures.

Drug Profile: Alendronate (Fosamax)

Alendronate, commonly known by the brand name Fosamax, is a frequently prescribed bisphosphonate used to treat and prevent osteoporosis in postmenopausal women and men.

How it Works: Alendronate prevents bone breakdown and increases bone thickness by attaching to the bone and slowing the action of osteoclasts.
Administration: It is typically taken as an oral tablet. It must be taken on an empty stomach first thing in the morning with a full glass of plain water. Patients must remain upright (sitting or standing) for at least 30 minutes after taking the dose and before consuming any other food, drink, or medication to ensure proper absorption and minimize esophageal irritation.
Side Effects: The most common side effects are gastrointestinal, including heartburn, stomach pain, and nausea. A rare but serious complication is osteonecrosis of the jaw (ONJ), where the jawbone fails to heal, often after an invasive dental procedure. Another rare risk is an atypical fracture of the thigh bone.

An Alternative First-Line Option: Denosumab (Prolia)

Denosumab, sold under the brand name Prolia, is another common medication for osteoporosis. It is a monoclonal antibody and works differently than bisphosphonates. It is often used for individuals who cannot tolerate bisphosphonates or for those at a high risk of fracture.

How it Works: Denosumab is a RANKL inhibitor. It works by blocking a protein called RANK ligand (RANKL), which is essential for the formation, function, and survival of osteoclasts. By inhibiting RANKL, denosumab reduces bone resorption, increases bone density, and lowers fracture risk. Studies have shown it can increase lumbar spine BMD by over 20% after 10 years of treatment.
Administration: Denosumab is administered as a subcutaneous injection (a shot under the skin) once every six months by a healthcare professional. This can be more convenient for patients than a daily or weekly pill.
Side Effects: Common side effects include back, muscle, and limb pain. Like bisphosphonates, it carries a rare risk of osteonecrosis of the jaw and atypical femoral fractures. A significant concern with denosumab is the risk of a rapid rebound in bone loss and an increased risk of spinal fractures if the medication is stopped or delayed, so continuous treatment or transition to another medication is crucial.

Comparison of Alendronate and Denosumab


Feature	Alendronate (Bisphosphonate)	Denosumab (RANKL Inhibitor)
Mechanism	Slows down bone-resorbing cells (osteoclasts).	Blocks the formation and activation of osteoclasts.
Administration	Oral pill, typically taken weekly or daily on an empty stomach.	Subcutaneous injection every 6 months by a healthcare provider.
Common Side Effects	Heartburn, stomach upset, nausea.	Back pain, muscle aches, pain in extremities.
Rare, Serious Risks	Osteonecrosis of the jaw (ONJ), atypical femoral fractures.	Osteonecrosis of the jaw (ONJ), atypical femoral fractures, rebound bone loss upon stopping.
Use Case	Often the first-line medication prescribed.	A first-line option, especially for those who can't take bisphosphonates or are at high risk.

Other Osteoporosis Medications

While bisphosphonates and denosumab are common, other classes of drugs are available:

Anabolic (Bone-Building) Agents: These drugs work by stimulating new bone formation. They include teriparatide (Forteo), abaloparatide (Tymlos), and romosozumab (Evenity). These are typically reserved for patients with very low bone density or those who have had fractures despite other treatments. Romosozumab has a dual effect, both increasing bone formation and reducing bone loss.
Hormone-Related Therapy: Estrogen therapy can help maintain bone density, especially when started soon after menopause, but it carries risks like blood clots and certain cancers. Raloxifene (Evista) is a selective estrogen receptor modulator (SERM) that provides bone benefits without some of estrogen's risks.

Lifestyle's Role in Bone Health

Medication is most effective when combined with healthy lifestyle choices. Key recommendations include:

Adequate Calcium and Vitamin D: Calcium is crucial for bone strength, and Vitamin D helps the body absorb it. Adults aged 51 and older should aim for appropriate daily intake of calcium and vitamin D, as recommended by healthcare guidelines.
Weight-Bearing Exercise: Activities like walking, jogging, and strength training help build and maintain strong bones.
Avoid Smoking and Excessive Alcohol: Smoking weakens bones, and consuming more than two alcoholic drinks per day can decrease bone formation.
Fall Prevention: Simple measures like installing grab bars, ensuring good lighting, and wearing supportive shoes can prevent falls that lead to fractures.

Conclusion

For managing osteoporosis, bisphosphonates like Alendronate and RANKL inhibitors like Denosumab are two of the most effective and commonly prescribed drug classes. Alendronate is a widely used oral medication that slows bone breakdown, while Denosumab is a twice-yearly injection that blocks the cells responsible for bone loss. The choice between them depends on a patient's medical history, fracture risk, potential side effects, and personal preference for administration. Both treatments, especially when paired with a healthy lifestyle, play a vital role in reducing fracture risk and preserving bone health for individuals with osteoporosis.

For more information on osteoporosis treatments, you can visit the Mayo Clinic.

Frequently Asked Questions

Bisphosphonates are the most commonly prescribed class of medications for osteoporosis, with Alendronate (Fosamax) being a frequent first choice.

Alendronate works by preventing bone breakdown and increasing bone density. It belongs to a class of drugs called bisphosphonates that slow down the cells responsible for bone resorption.

Denosumab is a monoclonal antibody, not a bisphosphonate. It works by blocking a protein (RANKL) essential for the formation of bone-resorbing cells. It is administered as an injection every six months, whereas many bisphosphonates are oral pills.

Oral bisphosphonates like Alendronate can cause heartburn and stomach upset. Denosumab can cause muscle or back pain. Both carry a rare risk of serious side effects like osteonecrosis of the jaw and atypical thigh bone fractures.

You should not stop taking osteoporosis medication without consulting your doctor. Discontinuing Denosumab, for instance, can cause a rapid loss of bone density and an increased risk of spinal fractures.

Yes. Denosumab (Prolia) is an injection given every six months. Some bisphosphonates, like zoledronic acid (Reclast), are given as an intravenous (IV) infusion once a year.

Key lifestyle changes include ensuring adequate intake of calcium and vitamin D, performing regular weight-bearing exercises, avoiding smoking, and limiting alcohol consumption. Preventing falls is also crucial to avoid fractures.