Fosamax Side Effects

Generic Name: alendronate

Note: This page contains information about the side effects of alendronate. Some of the dosage forms included on this document may not apply to the brand name Fosamax.

Not all side effects for Fosamax may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to alendronate: oral solution, oral tablet, oral tablet effervescent

In addition to its needed effects, some unwanted effects may be caused by alendronate (the active ingredient contained in Fosamax). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking alendronate:

More common
  • Abdominal or stomach pain
Less common
  • Difficulty with swallowing
  • heartburn
  • irritation or pain of the esophagus
  • muscle pain
  • Skin rash
Incidence not known
  • Abdominal or stomach cramps
  • blistering, peeling, or loosening of the skin
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • bone, joint, or muscle pain, severe and occasionally incapacitating
  • chest pain
  • chills
  • confusion
  • convulsions
  • cough
  • diarrhea
  • difficulty with breathing
  • difficulty with moving
  • heartburn
  • heavy jaw feeling
  • hives or welts
  • irregular heartbeats
  • itching
  • joint pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • loosening of a tooth
  • muscle aching or cramping
  • muscle cramps in the hands, arms, feet, legs, or face
  • numbness and tingling around the mouth, fingertips, or feet
  • pain or burning in the throat
  • pain, swelling, or numbness in the mouth or jaw
  • rapid weight gain
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • redness of the skin
  • shortness of breath
  • sore throat
  • sores, ulcers, or white spots on the lips or tongue or inside the mouth
  • swollen joints
  • tingling of the hands or feet
  • tremor
  • unusual tiredness or weakness
  • unusual weight gain or loss
  • vomiting

Some of the side effects that can occur with alendronate may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common
  • Constipation
  • diarrhea
  • full or bloated feeling
  • gas
  • headache
  • nausea
Incidence not known
  • Blurred vision or other change in vision
  • dizziness or lightheadedness
  • eye pain
  • feeling of constant movement of self or surroundings
  • general feeling of discomfort or illness
  • hair loss or thinning of the hair
  • sensation of spinning
  • sensitivity of the eye to light
  • tearing

For Healthcare Professionals

Applies to alendronate: oral solution, oral tablet, oral tablet effervescent


Generally, alendronate (the active ingredient contained in Fosamax) has been well tolerated. Adverse effects usually have been mild when patients adhered to prescribing instructions.

Fever has been reported in patients receiving intravenous infusions of alendronate.

Asthenia and rare instances of peripheral edema have been reported in postmarketing experience.


Postmarketing experience has reported esophagitis, esophageal erosions, esophageal ulcers, rarely esophageal stricture or perforation and oropharyngeal ulceration.

The combination of alendronate (the active ingredient contained in Fosamax) and naproxen has been reported as synergistic for development of gastric ulcers.

Gastrointestinal side effects have included abdominal pain, nausea, dyspepsia, constipation, diarrhea, and flatulence. Regurgitation, esophageal ulcer, vomiting, dysphagia, abdominal distention, and gastritis also have occurred. Rarely, taste perversion has been reported. The frequency of adverse effects increased with higher dosages.

Several cases of ulcerative esophagitis have been reported in patients receiving alendronate. Patients with preexisting esophageal disorders and those who take alendronate with little or no water and lie down immediately following ingestion may be at an increased risk.


Metabolic side effects have included reductions in serum calcium and phosphate levels as a result of the inhibition of bone resorption. These reductions generally have been mild, asymptomatic, and transient. Symptomatic hypocalcemia has been reported in postmarketing experiences.


Musculoskeletal side effects have included bone, muscle or joint pain in approximately 4% of patients. In postmarketing experience, severe and occasionally incapacitating bone, joint and/or muscle pain, have been infrequently reported. Localized osteonecrosis of the jaw, generally associated with tooth extraction and/or local infection, often with delayed healing, has been reported rarely. Joint swelling has been reported postmarketing experience. Also, low-energy femoral shaft and subtrochanteric fractures have been reported in postmarketing experience.

Nervous system

Nervous system side effects have been rare. Headaches have been reported in fewer than 3% of patients. Dizziness and vertigo have been reported in postmarketing experience.


Dermatologic side effects have included rare reports of rash and erythema. Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported in postmarketing experiences.


Ocular side effects have included rare incidences of iritis, scleritis, uveitis, and nonspecific transitory conjunctivitis.


Respiratory side effects have included a case report of an asthma attack induced by alendronate (the active ingredient contained in Fosamax) Postmarketing side effects have included exacerbations of asthma.

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