Alendronic 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 and increasing bone mineral density.

Prescribing in practice

• Take on rising on an empty stomach with plain water, remaining upright and not eating, drinking or taking other medicines for the advised period afterwards, to prevent severe oesophageal irritation and ulceration.
• Correct vitamin D deficiency and hypocalcaemia before starting, and ensure adequate calcium and vitamin D intake during treatment.
• Counsel on the rare risks of osteonecrosis of the jaw and atypical femoral fractures, with dental review before and during therapy and reporting of thigh or groin pain.

Monitoring

Monitor adherence, renal function and calcium/vitamin D status, and review the need for continued treatment with a drug-holiday assessment after a defined treatment period.

Counselling the patient

• Swallow the tablet whole with a full glass of plain water and stay upright; do not lie down for the advised interval.
• Report any difficulty or pain on swallowing, heartburn, new thigh or groin pain, or dental problems.

Evidence & guidelines

The Fracture Intervention Trial demonstrated reduced vertebral and hip fracture risk, and NICE recommends oral bisphosphonates as first-line osteoporosis therapy.