What Is Alendronate and How Does It Work?

Alendronate is used to prevent and treat certain types of bone loss (osteoporosis) in adults. Osteoporosis causes bones to become thinner and break more easily. Your chance of developing osteoporosis increases as you age, after menopause, or if you are taking corticosteroid medications (such as prednisone) for a long time.

  • Alendronate works by slowing bone loss. This effect helps maintain strong bones and reduces the risk of broken bones (fractures). Alendronate belongs to a class of drugs called bisphosphonates.
  • Alendronate is available under the following different brand names: Fosamax, Binosto, and Fosamax Plus D.

What Are Dosages of Alendronate?

Dosages of Alendronate:

Dosage Forms and Strengths


  • 5 mg
  • 10 mg
  • 35 mg
  • 40 mg
  • 70 mg

Tablet for solution (effervescent)

  • 70 mg

Solution, oral

  • 70 mg/75mL

Dosage Considerations – Should be Given as Follows:


Prevention in postmenopausal women

  • 5 mg orally once daily or 35 mg orally once weekly

Treatment in postmenopausal women and men

  • 10 mg orally once daily or 70 mg orally once weekly

Glucocorticoid-Induced Osteoporosis

  • Males and females: 5 mg orally once daily (10 mg/day for postmenopausal women not on hormone replacement therapy)

Paget Disease

  • 40 mg/day orally for 6 months

Dosing Modifications

  • Mild-to-moderate renal impairment (CrCl 35-60 mL/min): Dose adjustment not necessary
  • Severe renal impairment (CrCl less than 35 mL/min): Not recommended


  • Take only in the morning, not at bedtime or before arising
  • Take the tablet with a full glass of water (6-8 oz) at least 30 minutes before the first food or drink of the day, in an upright position
  • Administer oral solution with at least 2 ounces of water
  • Swallow with plain water only; mineral water, coffee, juice, or other beverages severely reduces the bioavailability
  • Swallow tablet whole; do not suck or chew
  • Do not lie down for 30 minutes after taking the drug; sit or stand upright
  • Despite a long terminal half-life (10 years), the bone-incorporated drug is not pharmacologically active
  • If dietary intake is inadequate, patients should receive calcium supplements and vitamin D

Limitation of Use

  • Optimal duration of use not determined; for patients at low risk for fracture, consider drug discontinuation after 3-5 years of use
  • Pediatric: Safety and efficacy not established

What Are Side Effects Associated with Using Alendronate?

Common side effects of alendronate include:

Less common side effects of alendronate include:

Serious side effects of alendronate include:

  • Severe pain (joints, bone, muscle, jaw, back, or heartburn)
  • Chest pain
  • Difficulty swallowing
  • Bloody stools
  • Eye pain
  • Skin blisters
  • Swelling of the face, tongue, or throat

Postmarketing side effects of alendronate reported include:

  • Body as a whole: Hypersensitivity reactions including hives and skin swelling; transient muscle pain, feeling unwell (malaise), weakness/lack of energy, and fever; symptomatic hypocalcemia; swelling of extremities
  • Gastrointestinal: Esophagitis, esophageal erosions, esophageal ulcers, esophageal stricture or perforation, and mouth or throat ulceration; gastric or duodenal ulcers
  • Localized osteonecrosis of the jaw, generally associated with tooth extraction and/or local infection with delayed healing
  • Musculoskeletal: Bone, joint, and/or muscle pain, occasionally severe, and incapacitating; joint swelling; low-energy femoral shaft and subtrochanteric fractures
  • Nervous system: dizziness, spinning sensation (vertigo)
  • Pulmonary: Acute asthma exacerbations
  • Skin: Rash (occasionally with photosensitivity), itching, hair loss, severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis
  • Special Senses: Uveitis, scleritis, or episcleritis, cholesteatoma of the external auditory canal (focal osteonecrosis)

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Alendronate?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

What Are Warnings and Precautions for Alendronate?


This medication contains alendronate. Do not take Fosamax, Binosto, or Fosamax Plus D if you are allergic to alendronate or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity
  • Hypocalcemia
  • Abnormalities of the esophagus delaying esophageal emptying such as stricture or achalasia
  • Inability to stand or sit upright for 30 minutes

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Alendronate?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Alendronate?"


  • May cause local irritation of upper gastrointestinal (GI) mucosa
  • Take with plain water only, not coffee, juice, or mineral water; sit or stand upright for at least 30 minutes after administration
  • Hypocalcemia reported with the use of bisphosphonates; correct hypocalcemia before therapy; ensure adequate calcium and vitamin D intake
  • Conjunctivitis, uveitis, episcleritis, and scleritis reported with alendronate use; perform the ophthalmic evaluation in patients with signs of ocular inflammation
  • Avoid concomitant polyvalent cation-containing medications
  • Osteonecrosis of the jaw can occur spontaneously and is generally associated with tooth extraction and/or local infection with delayed healing; known risk factors include invasive dental procedures (e.g., tooth extraction, dental implants, boney surgery), diagnosis of cancer, concomitant therapies (e.g., chemotherapy, corticosteroids, angiogenesis inhibitors), poor oral hygiene, and co-morbid disorders; risk of osteonecrosis of the jaw may increase with duration of exposure to bisphosphonates
  • Not recommended in severe renal impairment (CrCl less than 35 mL/min)
  • In Paget disease, the drug is available only through Paget's Patient Support Program with Pharma Care Specialty Pharmacy (800-238-7828 x58197) distribution system for a 40-mg dosage regimen
  • Risk of severe bone, joint, or muscle pain; discontinue therapy in patients who experience severe symptoms of pain; avoid use in patients with a history of these symptoms in association with bisphosphonate therapy
  • Possible increased risk of atypical subtrochanteric and diaphyseal femur fractures; may consider discontinuing therapy after 3-5 years in patients at low-risk for fracture; following discontinuation, re-evaluate fracture risk periodically; consider periodic reevaluation of the need for continued bisphosphonate therapy, particularly if the treatment lasts more than 5 years; patients with new thigh or groin pain should be evaluated to rule out a femoral fracture
  • Use effervescent tablet with caution in sodium-restricted patients (tablet contains 650 mg of sodium)
  • Esophageal cancer risk (July 21, 2011, FDA safety communication):
    • Conflicting findings exist from studies evaluating the risk of esophageal cancer with oral bisphosphonates
    • Esophagitis, dysphagia, esophageal ulcers, esophageal erosions, and esophageal stricture reported with oral bisphosphonates; risk is higher in patients unable to closely follow dosing instructions (e.g., sitting up or standing after administration and taking with a full glass of water); use with caution in patients with dysphagia, esophageal disease, gastritis, duodenitis, or ulcers; discontinue use if new or worsening symptoms develop
    • An ongoing review of data from published studies to evaluate whether the use of oral bisphosphonates is associated with an increased risk of cancer of the esophagus is currently being conducted by FDA
    • FDA has not concluded that taking an oral bisphosphonate increases the risk of esophageal cancer
    • Data are insufficient to recommend endoscopic screening of asymptomatic patients
    • FDA will continue to evaluate all available data supporting safety and effectiveness of bisphosphonates and will update the public when more information becomes available
    • Instruct patients to contact their healthcare provider if they develop symptoms of esophagitis (e.g., swallowing difficulties, chest pain, new or worsening heartburn, trouble or pain when swallowing)

Pregnancy and Lactation

  • Use alendronate with caution during pregnancy if the benefits outweigh the risks. Animal studies show risk and human studies are not available or neither animal nor human studies were done.
  • It is unknown whether alendronate is excreted in the milk; use caution if breastfeeding.
Medscape. Alendronate.
RxList. Fosamax Side Effects Center.

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