The Misconception of a Market Withdrawal
Many people believe the osteoporosis drug Fosamax (alendronate sodium) was removed from the market due to a recall, but this is incorrect [1.3.1]. Brand-name Fosamax has not been recalled in the U.S. [1.3.1]. The perception of its disappearance is primarily due to two major factors: the expiration of its patent and the emergence of significant, well-publicized health risks that led to extensive litigation and updated FDA warnings.
First approved by the FDA in 1995, Fosamax became a leading treatment for osteoporosis [1.3.1, 1.4.1]. It belongs to a class of drugs called bisphosphonates, which work by slowing down bone loss [1.3.1]. However, in February 2008, Merck & Company's patent for Fosamax expired, opening the floodgates for generic versions [1.7.2, 1.7.4]. This led to a dramatic drop in the market share for the brand-name drug, as generic alendronate became widely available at a much lower cost [1.7.4]. Within the first 30 days of generic availability, Fosamax lost 84% of its retail market share [1.7.4]. While there have been isolated recalls of specific batches of the generic version, alendronate, due to manufacturing issues like impurity levels, the drug itself remains available [1.2.1, 1.3.1].
The Real Story: Severe Side Effects and FDA Warnings
The true controversy surrounding Fosamax centers on severe side effects that were not adequately warned about for years. These concerns spawned thousands of lawsuits and forced the FDA to mandate significant label changes [1.5.4].
Osteonecrosis of the Jaw (ONJ)
One of the most severe risks linked to Fosamax is Osteonecrosis of the Jaw (ONJ), a condition where the jawbone begins to weaken and die due to a lack of blood flow [1.5.2, 1.5.6]. This can cause severe pain and disfigurement [1.5.1]. The risk of ONJ is particularly elevated for patients undergoing invasive dental procedures like tooth extractions [1.5.6]. After increasing reports of this condition, the FDA urged Merck to update its labeling, and a warning about ONJ was first added to the Fosamax label in 2005 [1.3.1, 1.5.2]. This led to a wave of litigation. A multidistrict litigation (MDL No. 1789) was established in New York to handle these cases, and in 2013, Merck settled approximately 1,200 ONJ lawsuits for $27.7 million [1.4.6, 1.9.1].
Atypical Femur Fractures (AFF)
Another major safety concern is the risk of atypical femur fractures—unusual and severe breaks in the thigh bone that can occur with little to no trauma [1.4.1]. Studies revealed that long-term use of Fosamax could, paradoxically, make bones more brittle and susceptible to these specific types of fractures [1.4.3, 1.4.6]. The FDA became aware of these risks around 2008 and, after its own task force investigation, required Merck to add a prominent warning to the Fosamax label about atypical femoral fractures in 2011 [1.4.1].
This issue has been the subject of a prolonged and complex legal battle. More than 4,000 lawsuits were filed alleging Merck failed to warn consumers about the fracture risk [1.4.4]. These cases were consolidated into another MDL (No. 2243) in New Jersey [1.4.6]. Merck argued that its failure-to-warn claims should be preempted by federal law, stating the FDA had initially rejected its proposed warning language [1.4.2]. This legal fight went through multiple courts, including the U.S. Supreme Court [1.4.3]. As of June 2025, after the Supreme Court declined to hear a recent appeal from Merck, hundreds of these revived lawsuits are cleared to move forward toward trial [1.2.3, 1.4.3].
Comparison of Osteoporosis Medications
Patients and doctors must weigh the benefits of bisphosphonates against their risks. Here is a comparison of alendronate with other common osteoporosis treatments:
| Feature | Alendronate (Fosamax) | Denosumab (Prolia) | Ibandronate (Boniva) |
|---|---|---|---|
| Drug Class | Bisphosphonate [1.8.3] | Monoclonal Antibody (RANKL Inhibitor) [1.8.3] | Bisphosphonate [1.8.3] |
| Administration | Oral pill (daily or weekly) [1.8.1] | Subcutaneous injection every 6 months [1.8.1] | Oral pill (monthly) or IV infusion every 3 months [1.8.1] |
| Primary Function | Slows bone breakdown [1.8.1] | Blocks protein responsible for bone breakdown [1.8.3] | Slows bone breakdown [1.8.3] |
| Common Side Effects | Heartburn, stomach upset, esophageal irritation [1.8.1] | Muscle and bone pain [1.8.3] | Heartburn, stomach upset [1.8.1] |
| Major Controversies | Atypical Femur Fractures, Osteonecrosis of the Jaw (ONJ) [1.8.1] | Potential high risk of spinal fractures after stopping [1.8.1] | Less data supporting non-spinal fracture prevention [1.8.3] |
Authoritative Link: For detailed patient information on alendronate, consult the FDA label.
Conclusion: A Legacy of Generics and Litigation
In summary, the narrative that Fosamax was taken off the market is a simplification of a more complex reality. The brand-name drug's prominence faded due to market forces following its patent expiration in 2008, allowing affordable generic alendronate to dominate [1.7.4, 1.7.5]. Simultaneously, its legacy became intertwined with serious safety concerns—specifically osteonecrosis of the jaw and atypical femur fractures—which were not disclosed to patients for many years [1.5.4]. These risks led to mandatory FDA warning label updates and have resulted in thousands of lawsuits that continue to be litigated over a decade later [1.4.3, 1.9.1]. While alendronate remains a widely prescribed and effective treatment for osteoporosis, its history serves as a critical case study in post-market drug safety monitoring and pharmaceutical liability.
