Medication-related osteonecrosis of the jaw (bisphosphonates and similar drugs)

Osteonecrosis means bone tissue that has lost its blood supply or its ability to repair. In the jaw, it presents as an area of bone exposed through the gum that does not heal over an extended period, often after dental treatment or without an obvious trigger. Clinicians now usually call it medication-related osteonecrosis of the jaw, because several groups of bone-active medicines have been linked to it.

Bisphosphonates slow the rate at which bone is broken down in the body, which is why they reduce fracture risk. The jaw is thought to be vulnerable because its bone turns over quickly, sits beneath a thin layer of gum exposed to bacteria and is repeatedly stressed by chewing and dental procedures.

The NHS osteoporosis page states that the condition is a rare side effect linked with bisphosphonate use, most often with high-dose intravenous treatment used in cancer rather than with osteoporosis treatment. Beyond the type and duration of treatment, the other factors generally recognised include dental extractions or surgery while on treatment, poor oral hygiene, gum disease, ill-fitting dentures, smoking and some other medicines or conditions that impair healing.

For most people taking tablets for osteoporosis the absolute risk is small, and the benefit of preventing fractures usually outweighs it. Prescribers revisit that balance at review points.

The NHS side-effects page for alendronic acid lists signs that may indicate jawbone damage: a loose tooth, mouth sores, or swelling or pain in the mouth or jaw. People also describe numbness or heaviness of the jaw, discharge, bad taste or an extraction socket that is not healing.

• Pain, swelling or a lump in the gum or jaw.

• A tooth that becomes loose without injury.

• A sore in the mouth or exposed bone that does not heal.

• Numb or heavy feeling in the jaw, or a persistent discharge.

The NHS says patients should inform their dentist that they are taking alendronic acid, as there is a very small chance of jawbone damage with implants or extraction and alternative treatments may be recommended. The osteoporosis page adds that a dental check-up may be needed before starting bisphosphonates if there is a history of dental problems.

Sensible steps include completing necessary dental work before starting, brushing twice daily, cleaning between teeth, attending regular check-ups and keeping dentures well fitted. For people about to start intravenous treatment for cancer, hospitals commonly ask for a dental assessment first. Do not stop a bone medicine because of a dental appointment; discuss it with the prescriber and dentist, who can coordinate timing.

Diagnosis is clinical, based on exposed or non-healing bone in someone with relevant medicine exposure and no history of radiotherapy to the head and neck. An X-ray or scan may show the extent. A biopsy is sometimes used to exclude other causes such as cancer or infection.

Management is usually conservative and led by an oral and maxillofacial or dental specialist: antiseptic mouthwash, treating infection with antibiotics, pain relief, and removal of loose fragments of bone. Surgery is reserved for more advanced or persistent cases. The prescriber and specialist together decide whether the medicine should be paused, and the bone medicine is not stopped without that discussion.

The NHS also notes that, in a small number of people who take alendronic acid for a long time, there are increased risks of rare inner-ear bone damage and certain thigh bone fractures, and says doctors weigh benefits against risks at periodic review. It lists new pain, weakness or discomfort in the thigh, hip or groin as a reason to seek urgent medical advice. Treatment usually lasts for years, and the NHS describes a reassessment, sometimes with a treatment pause, after the first period. See our guide to atypical femoral fractures and bisphosphonate holidays for more detail.

If you notice any of the warning signs, contact your dentist and your doctor promptly. Severe facial swelling, fever, difficulty swallowing or breathing, or spreading infection are emergencies for NHS 111, A&E or 999. For difficulty swallowing or worsening heartburn on bisphosphonate tablets, the NHS advice is to stop the tablet and call 111, as this may indicate injury to the food pipe.