Bisphosphonates

Question 1

What are examples of bisphosphonates?

Answer 1

• Alendronate
• Risedronate
• Pamidronate
• Zolindronate

Question 2

What are indications for bisphosphonate use?

Answer 2

• Osteoporosis (treatment and prevention)
• Paget’s disease of bone
• Treatment of hypercalcaemia of malignancy
• Treatment of bony metastases (pain reduction and fracture prevention)

Question 3

What are contraindications for bisphosophonate use?

Answer 3

• Oesophageal abnormalities which prolong emptying time (e.g. stricture or achalasia)
• Hypocalcaemia
• Pregnancy and breast-feeding

Question 4

When would you want to be cautious when using Bisphosphonates?

Answer 4

• Upper GI disorders
• Renal impairment

Question 5

What is the mechanism of action of bisphosphonates?

Answer 5

Analogues of pyrophosphate, which are incoporated into bone where they can exert their action. They interfere with osteoclasts by blocking the mevalonate pathway, acting to reduce bone resorption. The overall effect is an arrest in bone loss

Question 6

Why are bisphosphonates used in malignancy?

Answer 6

Increased osteoclast activity is seen due to PTH-related peptide or metastasis to bone. This activity is reduced by bisphosphonates

Question 7

What are adverse reactions to bisphosphonates?

Answer 7

• Gastrointestinal disturbance
• Gastric and oesophageal ulceration
• Renal toxicity (ensure adequate hydration)
• Rarely - rash, pruritis, erythema, photosensitivity, uveitis, scleritis
• Hypophosphataemia
• Osteonecrosis of jaw is rare but serious (normally only occurring if given IV)

Question 8

What drugs can bisphosphonates react with?

Answer 8

• Calcium salts
• NSAIDs

Question 9

How should individuals take bisphosphonates?

Answer 9

Standing upright, on an empty stomach and with plenty of water, not before bed. Adequate Vit D and calcium supplementation are needed

Question 10

What monitoring would you consider doing in someone with osteoporosis who was receiving bisphosphonates?

Answer 10

DEXA bone scan annually

Question 11

What things would you monitor in terms of safety for use of bisphosphonates?

Answer 11

• Symptoms of adverse side effects
• Calcium and phosphate levels