Zoledronic Acid

How it works

It binds avidly to bone mineral and inhibits osteoclast-mediated bone resorption by interfering with the mevalonate pathway, reducing bone turnover.

Prescribing in practice

• Correct hypocalcaemia and ensure adequate calcium and vitamin D before infusion, and avoid in significant renal impairment, as the infusion can worsen renal function and precipitate hypocalcaemia, which is more hazardous in frail older people.
• An acute-phase reaction with flu-like symptoms is common after the first infusion; ensure good hydration and the infusion is given over the recommended time.
• There is a risk of osteonecrosis of the jaw and atypical femoral fractures; assess dental health and ask about thigh or groin pain.

Monitoring

Check renal function and calcium (and vitamin D status) before each infusion and ensure adequate hydration, with attention to renal reserve in older patients.

Counselling the patient

• Flu-like symptoms may occur for a day or two after the infusion and usually settle.
• Maintain dental hygiene and report new dental problems, or persistent thigh, hip or groin pain.

Evidence & guidelines

The HORIZON trial showed once-yearly zoledronic acid reduced fractures in postmenopausal osteoporosis, and NICE recognises it as an option for osteoporosis treatment.