Table of ContentsView AllTable of ContentsWhat Is Fosamax?Common Side EffectsRare Side EffectsWhat to Do
Table of ContentsView All
View All
Table of Contents
What Is Fosamax?
Common Side Effects
Rare Side Effects
What to Do
Every drug has side effects and risks, and this is no less true for the drugFosamax (alendonic)prescribed for the treatment ofosteoporosis.
Although Fosamax is generally regarded as safe, there are some rare but potentially serious side effects associated with Fosamax, includingfemur (thigh bone) fracturesandosteonecrosis of the jaw(jaw bone deterioration ).
This article explains what risks Fosamax poses, both common and rare, and how the risks are managed for people prescribed this drug.
wetcake / Getty Images
Along with Actonel (risedronate) and Reclast (zoledronic acid), Fosamax (alendronate) belongs to a class of drugs calledbisphosphonatesused for the prevention and treatment of osteoporosis.Of the three, Fosamax is the most commonly prescribed.
Fosamax is also indicated for the treatment ofPaget’s disease of bone.
Fosamax was approved for use in the United States in 1995 and is approved for use in both females and males with osteoporosis as well as people diagnosed with Paget’s disease of bone.
The most common side effects involve the digestive tract, with symptoms ranging from mild to severe.
Common side effects of Fosamax include:
Many of these side effects may subside or disappear as your body adjusts to the medication. If these side effects don’t go away or get worse, be sure to let your doctor know.
The U.S. Food and Drug Administration (FDA) monitors and documents severe drug side effects and has issued several warnings highlighting the short- and long-term risks of Fosamax. These include:
Ironically, the side effects most concerning to the FDA are those associated with bones, the very structures in the body Fosamax are meant to support.
Focus on Fosamax and Bone Problems
Among some of the rare but serious side effects are bone demineralization (loss of bone mineral) andosteonecrosis(bone tissue death).
Over the longer term, Fosamax and the other bisphosphonates are linked to more serious concerns due to the progressive demineralization of bone:
FDA WarningIn 2010, the FDA issued a warning advising consumers that bisphosphonates like Fosamax were linked to rare bone fractures, calledsubtrochantericordiaphysealfemur fractures, that involve the top or middle part of the thigh bone.The FDA could not state definitively whether the fractures were drug-related. But, because these fractures are so rare (accounting for less than 1% of all hip or femur fractures), the FDA advises users to see their healthcare provider if signs like new thigh or groin pain develop.
FDA Warning
In 2010, the FDA issued a warning advising consumers that bisphosphonates like Fosamax were linked to rare bone fractures, calledsubtrochantericordiaphysealfemur fractures, that involve the top or middle part of the thigh bone.The FDA could not state definitively whether the fractures were drug-related. But, because these fractures are so rare (accounting for less than 1% of all hip or femur fractures), the FDA advises users to see their healthcare provider if signs like new thigh or groin pain develop.
In 2010, the FDA issued a warning advising consumers that bisphosphonates like Fosamax were linked to rare bone fractures, calledsubtrochantericordiaphysealfemur fractures, that involve the top or middle part of the thigh bone.
The FDA could not state definitively whether the fractures were drug-related. But, because these fractures are so rare (accounting for less than 1% of all hip or femur fractures), the FDA advises users to see their healthcare provider if signs like new thigh or groin pain develop.
To reduce the risk, the American Association of Clinical Endocrinologists (AACE) and the American College of Endocrinology (ACE) recommend that females at moderate risk for osteoporosis take a “drug holiday” from bisphosphonates after five years of oral use. Females at high risk are advised to take a drug holiday after 10 years of oral use.
A 2018 study inEndocrine Practicequestioned whether this practice is suitable for all people. According to the researchers, as many as 9.9% of females who took a drug break experienced a fracture within six years of stopping the drug. Most cases occurred within the fourth or fifth years.
These fractures, referred to aspathologic fractures, were thought to be due to bone mineral loss that occurred after treatment was stopped.
As worrisome as the warnings might seem, it is important to put things into perspective and weigh the benefits and risks of any drugs you take.
Among the considerations, it’s important to note that the risk of atypical femur fracture is low, affecting anywhere from three to 50 of every 100,000 Fosamax users per year.Even rarer is the risk of ONJ, affecting fewer than two of every 100,000 bisphosphonate users per year.
In contrast, Fosamax use is associated with as much as a 50% reduction in the risk ofhip fracturesin people with osteoporosis.
To this end, it’s important to have your condition regularly monitored if you are prescribed Fosamax. Most experts recommend a follow-up appointment every six months.
Who Is Most at Risk?The risk of atypical femur fractures appears to be greater the longer Fosamax is used. Some studies have reported that 94% of atypical fractures involved females who were on Fosamax for more than five years.Other studies suggest that risk is dose-related, with daily doses of 5 milligrams (mg) or lower posing minimal risk.For people with postmenopausal osteoporosis, the recommended dose is 10 mg daily.
Who Is Most at Risk?
The risk of atypical femur fractures appears to be greater the longer Fosamax is used. Some studies have reported that 94% of atypical fractures involved females who were on Fosamax for more than five years.Other studies suggest that risk is dose-related, with daily doses of 5 milligrams (mg) or lower posing minimal risk.For people with postmenopausal osteoporosis, the recommended dose is 10 mg daily.
The risk of atypical femur fractures appears to be greater the longer Fosamax is used. Some studies have reported that 94% of atypical fractures involved females who were on Fosamax for more than five years.
Other studies suggest that risk is dose-related, with daily doses of 5 milligrams (mg) or lower posing minimal risk.For people with postmenopausal osteoporosis, the recommended dose is 10 mg daily.
If a drug holiday is recommended, you should still continue to see your provider for follow-up appointments, getting regular blood tests,bone scans, andbone density testswhen recommended. If the risk of bone fracture is low following a three- to five-year drug holiday, some treaters will stop Fosamax permanently.
In the meantime, healthy lifestyle practices including regular exercise and weight loss are advised along with a diet rich in calcium and vitamin D.
Who Treats Osteoporosis?
9 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Abrahamsen B, Eiken P, Prieto-Alhambra D, Eastell R.Risk of hip, subtrochanteric, and femoral shaft fractures among mid and long term users of alendronate: nationwide cohort and nested case-control study.BMJ. 2016;353:i3365. doi:10.1136/bmj.i3365Bindin B, William A, Balasubramanian N, Sandhu J, Camacho P.Osteoporotic fractures during bisphosphonate drug holiday.Endocrine Pract.2018;24(2):163-169. doi:10.4158/EP171975.ORMerck & Co.Fosamax (alendronate sodium) tablets, for oral use.U.S. Food and Drug Administration.FDA drug safety communication: safety update for osteoporosis drugs, bisphosphonates, and atypical fractures. February 2018.Larsen MS, Schmal H.The enigma of atypical femoral fractures: a summary of current knowledge.EFORT Open Rev.2018 Sep;3(9):494–500. doi:10.1302/2058-5241.3.170070Kim JW, Kwak MK, Han JJ.Medication related osteonecrosis of the jaw: 2021 position statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons.J Bone Metab.2021 Nov;28(4):279–296. doi:10.11005/jbm.2021.28.4.279Zhu J, March L.Treating osteoporosis: risks and management.Aust Prescr.2022 Oct;45(5):150–157. doi:10.18773/austprescr.2022.054Camacho PM, Petak SM, Binkley N, et al.American Association of Clinical Endocrinologists/American College of Endocrinology Clinical practice guidelines for the diagnosis and treatment of postmenopausal osteoporosis—2020 update.Endocrine Pract. 2020;26(1):1-46. doi:10.4158/GL-2020-0524SUPPLAlwahhabi BK, Alsuwaine BA.Long-term use of bisphosphonates in osteoporosis.Saudi Med J.2017 Jun;38(6):604–608. doi:10.15537/smj.2017.6.19793Additional ReadingNational Institutes of Health: Osteoporosis and Related Bone Diseases National Resource Center.Osteoporosis Overview.
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Abrahamsen B, Eiken P, Prieto-Alhambra D, Eastell R.Risk of hip, subtrochanteric, and femoral shaft fractures among mid and long term users of alendronate: nationwide cohort and nested case-control study.BMJ. 2016;353:i3365. doi:10.1136/bmj.i3365Bindin B, William A, Balasubramanian N, Sandhu J, Camacho P.Osteoporotic fractures during bisphosphonate drug holiday.Endocrine Pract.2018;24(2):163-169. doi:10.4158/EP171975.ORMerck & Co.Fosamax (alendronate sodium) tablets, for oral use.U.S. Food and Drug Administration.FDA drug safety communication: safety update for osteoporosis drugs, bisphosphonates, and atypical fractures. February 2018.Larsen MS, Schmal H.The enigma of atypical femoral fractures: a summary of current knowledge.EFORT Open Rev.2018 Sep;3(9):494–500. doi:10.1302/2058-5241.3.170070Kim JW, Kwak MK, Han JJ.Medication related osteonecrosis of the jaw: 2021 position statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons.J Bone Metab.2021 Nov;28(4):279–296. doi:10.11005/jbm.2021.28.4.279Zhu J, March L.Treating osteoporosis: risks and management.Aust Prescr.2022 Oct;45(5):150–157. doi:10.18773/austprescr.2022.054Camacho PM, Petak SM, Binkley N, et al.American Association of Clinical Endocrinologists/American College of Endocrinology Clinical practice guidelines for the diagnosis and treatment of postmenopausal osteoporosis—2020 update.Endocrine Pract. 2020;26(1):1-46. doi:10.4158/GL-2020-0524SUPPLAlwahhabi BK, Alsuwaine BA.Long-term use of bisphosphonates in osteoporosis.Saudi Med J.2017 Jun;38(6):604–608. doi:10.15537/smj.2017.6.19793Additional ReadingNational Institutes of Health: Osteoporosis and Related Bone Diseases National Resource Center.Osteoporosis Overview.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Abrahamsen B, Eiken P, Prieto-Alhambra D, Eastell R.Risk of hip, subtrochanteric, and femoral shaft fractures among mid and long term users of alendronate: nationwide cohort and nested case-control study.BMJ. 2016;353:i3365. doi:10.1136/bmj.i3365Bindin B, William A, Balasubramanian N, Sandhu J, Camacho P.Osteoporotic fractures during bisphosphonate drug holiday.Endocrine Pract.2018;24(2):163-169. doi:10.4158/EP171975.ORMerck & Co.Fosamax (alendronate sodium) tablets, for oral use.U.S. Food and Drug Administration.FDA drug safety communication: safety update for osteoporosis drugs, bisphosphonates, and atypical fractures. February 2018.Larsen MS, Schmal H.The enigma of atypical femoral fractures: a summary of current knowledge.EFORT Open Rev.2018 Sep;3(9):494–500. doi:10.1302/2058-5241.3.170070Kim JW, Kwak MK, Han JJ.Medication related osteonecrosis of the jaw: 2021 position statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons.J Bone Metab.2021 Nov;28(4):279–296. doi:10.11005/jbm.2021.28.4.279Zhu J, March L.Treating osteoporosis: risks and management.Aust Prescr.2022 Oct;45(5):150–157. doi:10.18773/austprescr.2022.054Camacho PM, Petak SM, Binkley N, et al.American Association of Clinical Endocrinologists/American College of Endocrinology Clinical practice guidelines for the diagnosis and treatment of postmenopausal osteoporosis—2020 update.Endocrine Pract. 2020;26(1):1-46. doi:10.4158/GL-2020-0524SUPPLAlwahhabi BK, Alsuwaine BA.Long-term use of bisphosphonates in osteoporosis.Saudi Med J.2017 Jun;38(6):604–608. doi:10.15537/smj.2017.6.19793
Abrahamsen B, Eiken P, Prieto-Alhambra D, Eastell R.Risk of hip, subtrochanteric, and femoral shaft fractures among mid and long term users of alendronate: nationwide cohort and nested case-control study.BMJ. 2016;353:i3365. doi:10.1136/bmj.i3365
Bindin B, William A, Balasubramanian N, Sandhu J, Camacho P.Osteoporotic fractures during bisphosphonate drug holiday.Endocrine Pract.2018;24(2):163-169. doi:10.4158/EP171975.OR
Merck & Co.Fosamax (alendronate sodium) tablets, for oral use.
U.S. Food and Drug Administration.FDA drug safety communication: safety update for osteoporosis drugs, bisphosphonates, and atypical fractures. February 2018.
Larsen MS, Schmal H.The enigma of atypical femoral fractures: a summary of current knowledge.EFORT Open Rev.2018 Sep;3(9):494–500. doi:10.1302/2058-5241.3.170070
Kim JW, Kwak MK, Han JJ.Medication related osteonecrosis of the jaw: 2021 position statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons.J Bone Metab.2021 Nov;28(4):279–296. doi:10.11005/jbm.2021.28.4.279
Zhu J, March L.Treating osteoporosis: risks and management.Aust Prescr.2022 Oct;45(5):150–157. doi:10.18773/austprescr.2022.054
Camacho PM, Petak SM, Binkley N, et al.American Association of Clinical Endocrinologists/American College of Endocrinology Clinical practice guidelines for the diagnosis and treatment of postmenopausal osteoporosis—2020 update.Endocrine Pract. 2020;26(1):1-46. doi:10.4158/GL-2020-0524SUPPL
Alwahhabi BK, Alsuwaine BA.Long-term use of bisphosphonates in osteoporosis.Saudi Med J.2017 Jun;38(6):604–608. doi:10.15537/smj.2017.6.19793
National Institutes of Health: Osteoporosis and Related Bone Diseases National Resource Center.Osteoporosis Overview.
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