Bisphosphonates

Related Subjects: |Calcium Physiology | Hypercalcaemia |Hypophosphataemia |Hyperphosphataemia | Bisphosphonates | Osteoporosis | Osteonecrosis of the jaw

All trials showing benefits of Bisphosphonates in osteoporosis had patients on oral calcium and Vitamin D supplements too

About: Always check BNF or equivalent for prescribing advice

• Drug therapy is only part of osteoporotic fracture management along with Falls assessment, Lifestyle advice and Calcium and Vitamin D supplement
• Atypical femoral fractures are rare but have been reported with prolonged bisphosphonate treatment for osteoporosis. Review risks and benefits after 5 or more years of use.

Mode of action

• Synthetic analogues of pyrophosphate such that the normal P-O-P bond has been replaced with P-C-P. The new analogue binds to bone and cannot be hydrolysed.
• Inhibit osteoclasts and reduce bone resorption and increase bone mineral density and so maintains the hydroxyapatite crystal structure
• Bisphosphonates may have additional functions on bone metabolism such as on the mevalonate pathway
• The primary and main indication for prescription is not measured bone mineral density but fracture risk. This includes assessing the risk of falls and the likelihood of falls in the context of Bone mineral density.

Indications

• Osteoporosis - postmenopausal and steroid-induced
• Reduce vertebral fractures - etidronate, alendronate, risedronate and ibandronate
• Reduce hip fractures - alendronate , risedronate , ibandronate
• Hypercalcaemia, Malignant bone disease e.g. Multiple myeloma
• Paget's disease

Contraindications

• Hypocalcemia, pregnant or planning pregnancy and children
• Chronic kidney disease stages 4 or 5, Osteomalacia
• Vitamin D deficiency (until it is corrected)
• Oesophageal reactions - take standing up or sitting up with water and on an empty stomach
• Nausea, Peptic ulcer disease
• Osteonecrosis of the jaw following high-dose intravenous administration used for some cancer patients associated with a dental surgical procedure and it has been suggested that bisphosphonate treatment should be postponed until after any dental work to eliminate potential sites of infection.