IV Bisphosphonate Pregnancy: Contraindicated during pregnancy and breast-feeding, and not recommended in women of childbearing potential. There are no adequate data in pregnant women; animal studies showed reproductive toxicological effects including malformations, and the potential risk for humans is unknown. It is unknown whether zoledronic acid is excreted into human milk.

Zoledronic Acid

Brand names: Aclasta (osteoporosis), Zometa (oncology)

Zoledronic acid is an intravenous nitrogen-containing bisphosphonate used for osteoporosis and for skeletal complications of malignancy and hypercalcaemia; this page is framed for older patients.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 5 mg

Route: Intravenous infusion, given via a vented infusion line slowly at a constant rate; the infusion time must not be less than 15 minutes

Frequency: Once a year (osteoporosis); a single infusion (Paget's disease)

Max: A single dose should not exceed 5 mg

Fetched source is the Aclasta 5 mg solution for infusion SPC. OSTEOPOROSIS (post-menopausal osteoporosis, osteoporosis in men, and osteoporosis associated with long-term systemic glucocorticoid therapy): a single intravenous infusion of 5 mg once a year. The optimal duration of bisphosphonate treatment has not been established - the need for continued treatment should be re-evaluated periodically, particularly after 5 or more years of use. In patients with a recent low-trauma hip fracture, give the infusion at least two weeks after hip fracture repair, and a loading dose of 50,000 to 125,000 IU of vitamin D orally or intramuscularly is recommended before the first infusion. PAGET'S DISEASE: a single intravenous infusion of 5 mg, prescribed only by physicians with experience in Paget's disease of the bone; ensure adequate supplemental calcium corresponding to at least 500 mg elemental calcium twice daily for at least 10 days following administration. Re-treatment of Paget's disease consists of an additional 5 mg intravenous infusion after an interval of one year or longer from initial treatment in patients who have relapsed (limited data). Patients must be appropriately hydrated before administration - especially the elderly (65 years and over) and patients receiving diuretic therapy - and adequate calcium and vitamin D intake is recommended. Hepatic impairment: no dose adjustment required. Elderly (65 years and over): no dose adjustment necessary. Should not be used in children and adolescents below 18 years of age; no data available under 5 years. INDICATION CAVEAT: this SPC does not cover the oncology zoledronic acid products. The US label in this bundle (zoledronic acid injection) states 4 mg as a single intravenous infusion over no less than 15 minutes for hypercalcaemia of malignancy (retreatment after a minimum of 7 days), and 4 mg over no less than 15 minutes every 3 to 4 weeks for multiple myeloma and bone metastases from solid tumours where creatinine clearance is greater than 60 mL/min, with reduced doses of 3.5 mg (CrCl 50-60), 3.3 mg (CrCl 40-49) and 3 mg (CrCl 30-39) mL/min - US labelling, to be verified against the relevant UK SPC before use for those indications.

Dose adjustments

Renal

Contraindicated in patients with creatinine clearance less than 35 ml/min. No dose adjustment is necessary in patients with creatinine clearance of 35 ml/min or above. Creatinine clearance should be calculated using the Cockcroft-Gault formula on actual body weight before each dose, and serum creatinine monitoring should be considered in at-risk patients.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to zoledronic acid, to any bisphosphonates, or to any of the excipients
Hypocalcaemia
Severe renal impairment with creatinine clearance less than 35 ml/min
Pregnancy and breast-feeding

Side effects

Pyrexia (17.1% after the first infusion) and influenza-like illness; acute phase reactions
Myalgia, arthralgia, bone pain, back pain, pain in extremity (common)
Headache, dizziness (common)
Hypocalcaemia (common); hypophosphataemia (rare)
Nausea, vomiting, diarrhoea (common)
Atrial fibrillation (common); ocular hyperaemia (common)
Renal impairment, including rare renal failure requiring dialysis; osteonecrosis of the jaw; atypical subtrochanteric and diaphyseal femoral fractures (bisphosphonate class effects)

Interactions

Aminoglycosides and calcitonin: additive effect lowering serum calcium for prolonged periods - caution [US label]
Loop diuretics: increased risk of hypocalcaemia - exercise caution [US label]
Other potentially nephrotoxic medicinal products: use with caution [US label; the UK SPC also advises caution with medicinal products that could impact renal function]
Thalidomide: no dose adjustment of zoledronic acid 4 mg needed when co-administered [US label]
SPC section 4.5 was not retrieved in this fetch - the above are drawn from US labelling and must be supplemented from the full UK SPC

Clinical monograph

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.

Reference: NICE CG146; HORIZON-PFT Trial; NOGG Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways