What are the side effects of Fosamax (Alendronate)?

From the Guidelines

Fosamax (alendronate) can cause several side effects, including gastrointestinal issues, osteonecrosis of the jaw, and atypical femur fractures, and patients should be aware of these potential risks. The most common side effects of Fosamax include gastrointestinal issues such as heartburn, stomach pain, nausea, and acid reflux, which occur in about 10-30% of patients and can be minimized by taking the medication properly - with a full glass of plain water first thing in the morning, remaining upright for at least 30 minutes afterward, and not eating or drinking anything else during this time 1. More serious but rare side effects include:

• Osteonecrosis of the jaw (bone death in the jaw), which primarily affects patients undergoing dental procedures while on the medication, and atypical femur fractures after long-term use (typically over 5 years) 1
• Musculoskeletal pain, which can be severe in rare cases
• Eye inflammation and esophageal ulcers, which can occur particularly if the medication is not taken as directed These side effects result from Fosamax's mechanism of action as a bisphosphonate that inhibits bone resorption by binding to bone mineral and reducing osteoclast activity. Patients should report persistent or severe side effects to their healthcare provider immediately, as dosage adjustments or alternative treatments may be necessary. It is essential to note that the risk of serious adverse events, such as medication-related osteonecrosis of the jaw (MRONJ), bone pain, atrial fibrillation, and esophageal cancer, is rare, and the incidence of MRONJ associated with bisphosphonate use for osteoporosis ranged from less than one to 28 cases per 100,000 person-years of treatment 1. Additionally, the optimal duration of treatment with bisphosphonates is unclear, but some experts recommend discontinuation after 5 years with careful observation 1. Overall, patients should be aware of the potential risks and benefits of Fosamax and discuss any concerns with their healthcare provider.

From the FDA Drug Label

Alendronate sodium tablets, USP can cause serious side effects including: Esophagus problems Low calcium levels in your blood (hypocalcemia) Bone, joint, or muscle pain Severe jaw bone problems (osteonecrosis) Unusual thigh bone fractures The most common side effects of alendronate sodium tablets, USP are: Stomach area (abdominal) pain Heartburn Constipation Diarrhea Upset stomach Pain in your bones, joints, or muscles Nausea

The possible side effects of Fosamax (alendronate) include:

• Serious side effects:
  • Esophagus problems
  • Low calcium levels in the blood (hypocalcemia)
  • Bone, joint, or muscle pain
  • Severe jaw bone problems (osteonecrosis)
  • Unusual thigh bone fractures
• Common side effects:
  • Stomach area (abdominal) pain
  • Heartburn
  • Constipation
  • Diarrhea
  • Upset stomach
  • Pain in bones, joints, or muscles
  • Nausea 2 2

From the Research

Fosamax Side Effects

Fosamax, also known as alendronate, is a medication used to treat osteoporosis. The following are some potential side effects associated with Fosamax:

• Upper GI tract adverse events, including abdominal pain, nausea, dyspepsia, acid regurgitation, and musculoskeletal pain 3
• Esophagitis, including severe ulcerations, which can be caused by swallowing alendronate with little or no water, lying down during or after ingestion of the tablet, or continuing to take alendronate after the onset of symptoms 4
• Gastrointestinal side effects, such as nausea, which was the most often encountered symptom in a study of 759 female patients taking alendronate for at least 6 months 5
• Osteonecrosis of the jaw (ONJ), although the incidence of ONJ is rare and was not observed in a study of patients taking alendronate 6
• Other potential side effects, including withdrawals due to adverse events and serious adverse events, although the evidence for these is uncertain or of low certainty 6

Reducing the Risk of Side Effects

To reduce the risk of side effects, particularly esophagitis, the following recommendations have been made:

• Swallow alendronate with 180 to 240 ml (6 to 8 oz) of water on arising in the morning 4
• Remain upright for at least 30 minutes after swallowing the tablet and until the first food of the day has been ingested 4
• Discontinue the drug promptly if esophageal symptoms develop 4
• Follow the safety and absorption rules provided by the manufacturer, although non-compliance with these rules was not found to be significantly associated with upper GI tract complaints in one study 5