As a rheumatologist, I regularly depend on the expertise and advice of pharmacists. Medicine has gotten unbelievably complex. I truly believe that using a team-based approach is the best way of providing quality-care. In the clinic, I’m often asked questions about osteoporosis medications. Bisphosphonates are a class of medications that are commonly used to treat osteoporosis and they’ve come under a lot of scrutiny lately. One of the potential side effects is osteonecrosis of the jaw. For this week’s edition of RheumDoctor, one of our pharmacy students, Amy DeGennaro, teaches us: what is osteoporosis, what are bisphosphonates, and what is the real risk of osteonecrosis of the jaw.
Believe it or not, our bones are alive. Bones, in our bodies, are constantly renewing just like how our skin is constantly turning over. Our body’s ability to constantly build and breakdown bone is what allows us to grow and heal. This normal bone process over time results in our bones to get slightly thicker, however, we reach peak bone density in early adulthood. As we age we gradually start to lose bone though. Reduced bone mass puts us at risk for fractures which can be prevented by treatment. One of our best treatments (a group of drugs called bisphosphonates) slows the breakdown of bone and reduces the risk of a fracture, which is exactly what we want when treating osteoporosis.
What is Osteoporosis?
Osteoporosis is a disease in which bone density and quality are reduced, which means our bones become more porous and fragile, increasing the risk of fractures greatly. However, this bone loss occurs silently. Often there are no symptoms you would experience until your first fracture. It’s estimated that 200 million people worldwide suffer from osteoporosis. In the United States and in Europe, about 30% of all postmenopausal women have osteoporosis, and even worse at least 40% of these women will sustain one or more fragility fractures in their remaining lifetime.
But it is important not to forget that men suffer as well from osteoporosis.1
What is Osteonecrosis of the Jaw?
Exposed bone, in our mouths, that has persisted for more than 8 weeks. If a section of bone is fractured and does not heal it can cause blood flow to the bone to be interrupted causing bone death.
What Type of Treatment for Osteoporosis is related to Osteonecrosis of the Jaw?
Bisphosphonates: alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), zoledronic acid (Reclast)
Bisphosphonates work very well at inhibiting the breakdown of bone which results in an increase in the density of bone. Bisphosphonates have FDA approved indications for the treatment and prevention of post-menopausal osteoporosis, osteoporosis in men, and glucocorticoid (steroid) induced-osteoporosis. All bisphosphonates on the market have demonstrated reductions in vertebrae fractures and the majority of bisphosphonates show additional reduction in non-vertebral and hip fractures as well.
Such strong inhibition of bone breakdown may theoretically lead to an accumulation of microdamage to the bone which might compromise bone strength or delay fracture healing. However, we have seen, from studying the bones of women on long-term bisphosphonates that there is no increased microdamage, and clinical trials of bisphosphonates did not show evidence of altered healing.2
What are Risk Factors for Osteonecrosis of the Jaw for Patients?
- Drug-related risk factors
- Bisphosphonate potency (oral therapies less potent than intravenous)
- Duration of bisphosphonate treatment
- Individual risk factors
- Dental surgery
- Concomitant oral disease
- Periodontal disease
- Ill-fitted dental prosthesis
- Demographic factors
- Genetic factors
- Aggravating factors
- Heavy smoking
What is the Real Risk of Osteonecrosis?
Osteonecrosis of the jaw (ONJ) is an extremely rare adverse event for patients taking bisphosphonates for osteoporosis. Reports of bisphosphonate induced ONJ date back to the early 2000’s. Reviews of current data support that up to 80% of ONJ cases occurred in patients with various cancers. These patients were also treated for a long period of time with high-dose injectable bisphosphonates. It is important to note that these doses were 10x higher than doses used to treat osteoporosis.3
Cases, of ONJ in osteoporotic patients, are extremely rare – not one case was found in more than 3000 patients participating in the clinical trials with zoledronic acid and alendronate. And no causal link between ONJ and bisphosphonate therapy, in these patients, has been convincingly demonstrated.4
Although there are limitations to all studies, based on this information, the risk of ONJ in patients treated with bisphosphonates for osteoporosis is very low.
What does the American Dental Association Recommend?4
- Routine Dental Care
- Not modifying dental care solely because of bisphosphonates
- Recommend AGAINST discontinuing bisphosphonates just before dental procedures
You should not stop taking your osteoporosis medication without talking to your medical provider. Osteoporosis is a serious but very treatable medical condition. The risk of fractures in people suffering from osteoporosis is very real and serious, while the risk of bisphosphonate-induced osteonecrosis of the jaw is rare. Also, there are steps you and your doctor can take to help further reduce your risk by ensuring good dental hygiene and preventive dental checkups before starting and during treatment with these medications.
Remember it’s always about benefit versus risk!
Author: Amy R. DeGennaro, Doctor of Pharmacy Candidate graduating May 2017 from Albany College of Pharmacy and Health Sciences.
Reviewed and approved by: Jessica Farrell, PharmD. Clinical Pharmacist, The Center for Rheumatology/Associate Professor, Albany College of Pharmacy and Health Sciences
- International Osteoporosis Foundation. Available at: iofbonehealth.org
- Chapurlat RD, Arlot M, Burt-Pichat B, Chavassieux P, Roux JP, Portero-Muzy N, Delmas PD. Microcrack frequency and bone remodeling in postmenopausal osteoporotic women on long-term bisphosphonates: a bone biopsy study. J Bone Miner Res. 2007; 22:1502-1509.
- Hough FS, Brown SL, Cassim B, Davey MR. The safety of osteoporosis medication. South African Medical Journal. 2014;104.4: p279.
- Florence R, Allen S, Benedict L, Compo R, Jensen A, Kalogeropoulou D, Kearns A, Larson S, Mallen E, O’Day K, Peltier A, Webb B. Institute for Clinical Systems Improvement. Diagnosis and Treatment of Osteoporosis. Updated July 2013.