Fosamax is a classified bisphosphonate which improves bone mineral density by increasing bone formation while suppressing bone resorption or breakdown. Medcations in this category are being prescribed to prevent or treat bone problems such as osteoporosis, Paget’s disease or osteitis deformans, multiple myeloma, primary hyperparathyroidism and osteogenesis imperfecta. Nonetheless, these kind of drugs have also been found to cause severe conditions like osteonecrosis of the jawbone (ONJ) and atypical fracture of the femur.
Osteonecrosis of the jawbone (ONJ). ONJ is an infrequent but severe dental condition in which a fraction of a jawbone tissue is is divulge that does not heal as a result of poor blood supply until the bone tissue dies. There is no diagnostic exam that detects ONJ – it is only diagnosed when a jawbone is exposed which lasts for more than 8 weeks. Most of the time, pain or discomfort is felt by the patient which may be the result of an infection, swelling of soft tissue, drainage or exposure of the bone
To reduce the risk of ONJ, good oral hygiene with regular dental care should be observed by the patient. Also, inform your dentist prior to any dental procedure – even if it’s just a minor one – that you are taking Fosamax or other bisphosphonates. Moreover, patients who are about to start their bisphosphonate therapy are advised to wait until any immediate dental surgery is completed.
Atypical fracture of the femur. On October 13, 2010, the US Food and Drug Administration advised the addition of 2 atypical femur fractures on the label warnings of bisphosphonates which include Fosamax. Large research suggested that prolonged use of the drug could lead to the development of such fracture. Yet, FDA insisted that the benefits still outweighs the risk which seems to be pretty rare.
The FDA also suggested to physicians that a temporary halt might be important once the patient feels symptoms like  significant dull, aching pain in the thigh or groin. Additionally, some health care providers prescribe Fosamax for a period not exceeding 4 years. At the end of it all, treating osteoporosis aims to prevent the occurrence of fracture and definitely suffering from a Fosamax femur fracture is not part of the goal.

References: