Bisphosphonates

Question 1

What are bisphosphonates and how do they work?

Answer 1

Bisphosphonates are analogues of pyrophosphate that inhibit osteoclasts by reducing osteoclast recruitment and promoting osteoclast apoptosis, thereby decreasing bone demineralisation.

Question 2

What are the main clinical uses of bisphosphonates?

Answer 2

Prevention and treatment of osteoporosis, management of hypercalcaemia, treatment of Paget’s disease and pain from bone metastases.

Question 3

What oesophageal adverse effects are associated with bisphosphonates?

Answer 3

Oesophagitis and oesophageal ulcers, particularly with alendronate.

Question 4

What is osteonecrosis of the jaw and who is most at risk when taking bisphosphonates?

Answer 4

Osteonecrosis of the jaw is bone death of the jaw; it is much more common with IV bisphosphonates used for cancer, especially in patients with poor dental hygiene or recent dental procedures. Initial investigation is an orthopantomogram (panoramic dental X-ray).

Question 5

What fracture risk is increased with alendronate use?

Answer 5

Atypical stress fractures of the proximal femoral shaft.

Question 6

What acute phase symptoms may occur after bisphosphonate administration?

Answer 6

Fever, myalgia and arthralgia.

Question 7

Why can bisphosphonate therapy cause hypocalcaemia?

Answer 7

Reduced calcium efflux from bone, though it is usually clinically unimportant.

Question 8

What are the key counselling points for patients taking oral bisphosphonates?

Answer 8

Tablets should be swallowed whole with plenty of water while sitting or standing, taken on an empty stomach at least 30 minutes before breakfast or other medication and the patient must remain upright for at least 30 minutes after taking the tablet.

Question 9

What should be corrected before starting bisphosphonates?

Answer 9

Hypocalcaemia and vitamin D deficiency should be corrected before treatment. Calcium should only be prescribed if dietary intake is inadequate; vitamin D supplements are normally given.

Question 10

When might bisphosphonate treatment be stopped after 5 years?

Answer 10

If the patient is under 75 years old, has a femoral neck T-score greater than −2.5 and is at low fracture risk according to FRAX/NOGG.