Generic name: Alendronate.

Fosamax is a bisphosphonate, a group of drugs used to treat a variety of conditions that cause bone mass to be reabsorbed by the body. Fosamax slows down the loss of bone tissue and increases bone mass in women with osteoporosis. 

Quick Facts About Fosamax


Used to treat osteoporosis (the brittle-bone disease) in postmenopausal women. Also used to treat Paget’s disease (a painful weakening of the bones).

Fosamax Dosage

Take with a full glass of water in the morning, at  least 30 to 60 minutes before the first food, beverage, or other medication; best absorbed if you wait longer. Do not lie down for at least 30 minutes after taking medication. Treatment for osteoporosis lasts for years.

  • Usual adult dose: for postmenopausal osteoporosis — 10 milligrams daily. For Paget’s disease — 40 milligrams daily for 6 months.
  • Usual child dose: not prescribed for children.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Fosamax Side Effects

Overdose symptoms:

inflammation of the esophagus or stomach, severe heartburn, throat irritation, ulcer, upset stomach. If you suspect an overdose, immediately seek medical attention.

More common side effects: abdominal pain, constipation, diarrhea, indigestion, muscle and bone pain, nausea.

Less common Fosamax side effects: abdominal swelling, acid backup, difficulty swallowing, esophageal ulcers, gas, headache, vomiting. Rare side effects: taste changes, inflammation of the stomach, rash, skin redness.


Inform your doctor before combining Fosamax with aspirin or hormone replacement therapy.

Wait at least 30 minutes after taking Fosamax to take: antacids such as Riopan; calcium supplements such as Caltrate; vitamin supplements. Avoid smoking and alcohol while taking Fosamax. 

Special Cautions

Not recommended and normally not used in premenopausal women. However, if pregnant or planning to become pregnant, or breastfeeding, inform your doctor immediately.

No special precautions apply to seniors.

Not prescribed for children.

  • In order for Fosamax to be effective, you must take the tablets without food, other beverages, or other medications.
  • Your doctor may recommend taking calcium or vitamin D supplements if you have low blood levels of calcium (hypocalcemia) or vitamin D deficiency.
  • Weight-bearing exercise can contribute to strengthening bones.
  • Inform your doctor before taking if you have gastrointestinal or kidney problems.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Fosamax side effects, please contact your healthcare provider.