Alendronate and associated medication


Alendronate is a bisphosphonate compound that maintains the optimum levels of calcium in the blood and bone. It is commonly used by older individuals to avoid the complications of osteoporosis, weak bones, and some specific genetic conditions like Paget’s disease.  It is a medication sold under the name Fosamax. It acts by improving your bone mineral density and blood calcium.

Associated medication:

  • Risedronate.
  • Ibandronate.
  • Zoledronate
  • Denosumab.
  • Teriparatide.

Mechanisms of action:

  • Alendronic acid is a compound that reduces the osteoclastic activity in the bone. Osteoclasts are the cells that lead to the destruction of the bone leading to resorption of the bone. Resorption is a natural or physiological process but if it exceeds the normal rate, it leads to osteoporosis or other bone abnormalities. 
  • Alendronic acid reduces excess bone resorption and keeps the bone calcium levels normal.
  • Alendronic acid also improves the osteoblastic activity in bone, which means enhancing bone cell production. Thereby improving bone strength.
  • Therefore, reducing osteoclastic activity and improving osteoblastic activity improves the bone calcium and minerals and reduces osteoporosis.


  • The bioavailability of this medication is less than about 0.6-0.8%
  • The route of administration is oral.
  • This Medication when taken with food reduces its bioavailability.
  • It binds to the components of food and gets excreted. Hence it should not be consumed just before, with, or just after having food.
  • In the kidneys, it is processed and it is released in urine.
  • This medicine is excreted unchanged in urine to a larger extent.

Use of alendronate:

  • In chronic Kidney disease: in reduced kidney function, the calcium levels are not adequately maintained. Hence, alendronate is used to avoid secondary complications of CKD.
  • In osteoporosis: bone resorption occurs in women post menopause, older age group, chemotherapy, etc. Bone resorption is controlled or treated with alendronate.
  • In Paget’s disease: this is a congenital condition where the bones are brittle, and alendronate helps in maintaining or helping to improve bone strength.
  • In vitamin D deficiency: vitamin D is necessary for calcium absorption. Hence, alendronate is administered in such patients.
  • Corticosteroids induced osteoporosis.


  • Menopause induced osteoporosis.
  • Fracture cases: for the bones to heal, the calcium required is more. Hence, alendronate helps in the same.
  • Bow legs in young adults improve bone strength.
  • Knocked knees.

Indications for alendronate:

  • Osteoporosis
  • Paget’s disease
  • Vitamin D deficiency
  • Post menopausal women with predisposing factors for osteoporosis.
  • Patients on corticosteroids who have the chance of developing osteoporosis as a secondary complication to the preexisting condition.
  • Old age osteoporosis.
  • Fractures.
  • Weakness in bones and joints.


Side effects of alendronate:

  • Hypocalcemia: reduced calcium levels in the blood.
  • Gastrointestinal tract: constipation, gastric or duodenal ulceration, esophageal ulcers. Hence, this leads to varied symptoms like reduced or increased appetite in gastric and duodenal ulcers respectively. Other symptoms like abdomen pain, blood in the vomitus, and blood in stools.
  • Uveitis
  • Skin rashes, the altered texture of the skin.
  • Oesophageal cancer.
  • Body ache, joint pain.
  • Kidney: impaired functioning of the renal glands, chronic Kidney disease.

Contraindication to alendronate:

  • Hypersensitivity or allergy to alendronate.
  • Hypocalcemia.
  • Chronic Kidney disease and abnormal kidney functioning.
  • Achalasia cardia.
  • Frequent vomiting.
  • Pregnancy.
  • Lactation.
  • Intubated patient

Drug interactions with alendronate.

  • Alendronate interacts with food and alcohol and reduces its absorption.
  • It interacts with magnesium, iron, and other minerals which leads to reduced absorption.
  • Other drugs which interact with alendronate are aluminium hydroxide, aluminium carbonate, and aspirin.

Advice to follow:

  • Do not consume alendronate when you fall under the contraindicated category.
  • Do not use it if your blood calcium is low, it may lead to weak muscle contraction and arrhythmias.
  • Do not consume this medication with food.
  • After consumption of alendronate, the patient is advised to sit straight or stand straight for 20-40 minutes, for better results.
  • Sunlight exposure should be maintained each day adequately, especially in the early morning.
  • Proper dietary requirements should be fulfilled.
  • The mineral supplement should be taken 40-50 minutes before the alendronate administration.

Results of this medication:

  • Strong bones.
  • Reduced joint pain.
  • Avoids pathological fractures.
  • Early or quick healing of the fractured bone and early fusion of the same.
  • Improves bone calcium levels.
  • Ability to sit, and stand without pain.
  • Improve the quality of life.

About the associated medication:

  1. Risedronate: it is a medication that prevents the loss of calcium from bone and fractures in patients who are vulnerable. It is used to treat osteoporosis, and bone resorption disorders like Paget’s disease.
  2. Ibandronate: used to treat osteoporosis and used in chronic Kidney disease. It acts by improving osteoblastic activity and decreasing bone destruction.

Lifestyle modification along with alendronate.

  • Using conservative techniques like reaching with the cane, hooks, etc. Use of lifts rather than stairs, use of wheelchairs.
  • Reduce standing for a longer period of time. Avoid heavy lifting and strenuous activity.
  • Reducing bending activities, and excessive pressure on joints.
  • Sit , and stand upright after the administration of medication.
  • Proper timely intake of food and water.
  • Proper spacing between food, another mineral intake, and alendronate.
  • Adequate sleep and rest.
  • Check for proper heart rate, blood pressure, and vitals monitoring.
  • In mild osteoporosis, simple stretching and exercises.
  • Stopping alcohol and tobacco intake.


  • Alendronic acid is a bisphosphonate compound that is used in improving bone strength.
  • It helps improve or treat osteoporosis, Paget’s diseases, weakness in bones, etc. 
  • It has side effects like ulceration, body pain, constipation, and chronic Kidney disease.
  • Food and other medications should not be taken with alendronate.
  • Sir or stand upright after taking this medication for about 40 minutes.
  • It is advised for patients above 18 years of age.
  • It acts by improving the bone forming cells or osteoblasts and reducing the bone destructive cells like osteoclasts.
  • It should be consumed only on advice. Excessive and unprescribed usage leads to various serious effects.


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