What Is Alendronic Acid And What Are Its Uses?

alendronic acid

Alendronic Acid is a medication commonly used for the management of osteoporosis. The use of this drug has been found to be beneficial for improving bone mineral density and reducing the risk of fractures.

Here is a detailed discussion about this acid, its mechanism of action, side effects, and the recommended doses.

What is Alendronic Acid?

Alendronic acid belongs to the group of medications called bisphosphonates. They can strengthen your bones and make them more resistant to fractures. [1]

It is specifically used for the treatment of a bone disorder called osteoporosis that occurs due to the loss of bone mineral density. Osteoporosis usually affects people over 50 years of age. Degenerative changes occur in the bones as a result of aging, sometimes coupled with the hormonal changes, can cause bones to lose their vital minerals. 

As a result, bones become weak and porous. This triggers the development of osteoporosis.

The use of This acid is recommended as a preventive strategy for people who are at risk of osteoporosis. It can slow down bone loss and prevent the development of osteoporosis. 

It is also used for the management of malignant hypercalcemia, osteitis deformans, osteosarcoma, and Paget’s disease. [2] [3]

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The use of Alendronic acid restores bone mineral density making the bone stronger and healthier.  It is available in tablets and liquids.

How does Alendronic Acid work?

It helps to preserve bone mass by binding to bone hydroxyapatite. It can be taken by osteoclasts in the bone. Osteoclasts are the cells that cause the breakdown of bone tissues. Increased activities of osteoclasts can accelerate bone loss due to which the risk of osteoporosis increases substantially. 

The uptake of Alendronic acid by osteoclasts can induce apoptosis or cell death. This means it can induce the destruction of osteoclasts. As a result, the process of bone loss is slowed down. The inhibition of osteoclasts also leads to decreased bone resorption. These effects of Alendronic acid help to rebuild the bone mass and restore healthy bone density. [4]

Additionally, it may also increase the amount of calcium in the bones. It can make the bones stronger, more resistant to breakage and reduces the risk of developing osteoporosis. 

How long does Alendronic acid take to work?

The effect of this acid is usually noticeable about 1 month after you start using it. It takes time to regulate bone loss and bone resorption processes in order to improve bone mineral density. 

It may take about 6 to 12 months for Alendronic acid to restore normal bone mineral density and protect you against the risk of fractures. The improvement in the bone density can be assessed with the help of a bone densitometry test.

How effective is Alendronic acid at preventing fractures?

There is a high risk of fractures in patients who are diagnosed with osteoporosis or have broken a bone recently. [5]

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The regular use of Alendronic acid has been found to reduce the risk of developing fractures in the future significantly. 

In the case of menopausal women with a high risk of developing osteoporosis and fractures, it needs to be used for at least 12 months to reduce their chances of having a fracture.

How long Alendronic acid needs to be taken?

Since osteoporosis is a chronic disorder that can progress gradually over a period of time, the treatment also needs to be long-term. It is usually taken for several months. The exact duration of using it depends on the extent of bone loss, your bone mineral density, and the presence of risk factors such as family history or the use of medications that can accelerate bone loss. 

For example; patients who are undergoing long-term treatment with steroidal medications may need to use Alendronic Acid until they stop using steroids.

The decision to continue or stop using this acid can be taken based on the bone density tests performed at regular intervals. [6]

Your doctor will assess your bone mineral density and the risk of fractures at frequent intervals. Depending on the results, you will be advised to continue or stop using it. 

How long does the effect of Alendronic Acid last?

The effects of Alendronic Acid last for nearly 5 years after you stop taking it. However, the benefits may wear off gradually over a period of time. The benefits would can last longer if you have used this acid for a longer duration. 

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What is the recommended dose of Alendronic Acid?

The usual dose of Alendronic Acid for adults is 10 mg once a day or 70 mg once a week. It is advisable to consult a physician to know the right dosage suitable for you before you start using it. 

What are the side effects of Alendronic Acid?

The common side effects of this acid include: [7]

  • Loose motions
  • Constipation
  • Frequent headaches
  • Dizziness
  • Swelling in the joints of hands or legs
  • Pain in the muscles and joints
  • Skin rashes with itching 
  • Indigestion and bloating 
  • Fatigue
  • Feeling sleepy 
  • Hair loss

What are the contraindications for Alendronic Acid?

  • An allergic reaction
  • Inability to sit or stand for at least 30 minutes. (After taking alendronate you should not lie down for at least 30 minutes to prevent throat irritation due to the medicine.)
  • Having very low calcium levels in the blood 
  • Kidney disorders 
  • Pregnancy and breastfeeding
  • Undergoing chemotherapy for cancer 

Can healthy lifestyle changes help?

Adopting healthy lifestyle habits can improve the benefits of Alendronic Acid. You can keep your bones strong and healthy by making key lifestyle changes such as [8] [9]

  • Including foods high in calcium and vitamin D in your diet
  • Getting vitamin D from sunlight 
  • Reducing alcohol intake 
  • Quit smoking 
  • Staying physically active by performing exercises like walking and swimming 


Alendronic acid is an effective medication that can help to improve bone mineral density. The use of this acid is recommended for the treatment and prevention of osteoporosis. It can make bones denser and stronger, helping to prevent fractures. 


  1. https://www.medicines.org.uk/emc/product/5697/pil
  2. https://www.mdpi.com/1999-4923/12/3/293/htm
  3. https://adisinsight.springer.com/drugs/800012324
  4. https://www.drugbank.ca/drugs/DB00630
  5. https://www.ouh.nhs.uk/patient-guide/leaflets/files/11732Palendronic.pdf
  6. http://www.awmsg.org/docs/awmsg/medman/Guidance%20to%20Support%20the%20Safe%20Use%20of%20Long-term%20Oral%20Bisphosphonate%20Therapy.pdf
  7. https://www.nhs.uk/conditions/osteoporosis/treatment/
  8. https://www.nhs.uk/medicines/alendronic-acid/
  9. https://pubmed.ncbi.nlm.nih.gov/12578398/

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