IV Bisphosphonate Pregnancy: Not applicable. Avoid in women who may become pregnant.

Zoledronic Acid

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

Adult dose

Dose: Osteoporosis: 5 mg IV infusion over at least 15 min once yearly; Hypercalcaemia: 4 mg IV single dose

Route: IV infusion

Frequency: Once yearly (osteoporosis); single dose (hypercalcaemia/cancer)

Max: 5 mg/year (osteoporosis); 4 mg/dose (oncology)

Post-menopausal osteoporosis (Aclasta): 5 mg IV once yearly over minimum 15 minutes. Adequate hydration before infusion (500 mL saline). Calcium 1200 mg/day and Vit D 800–1000 IU/day supplementation. Oncology (Zometa): 4 mg IV every 3–4 weeks (different indication and dose).

Paediatric dose

Route: IV

Frequency: See specialist guidance

Max: Specialist guidance

Paediatric OI and steroid-induced osteoporosis: specialist use only. Not licensed for children for osteoporosis.

Dose adjustments

Renal

Contraindicated if eGFR <35 (Aclasta); eGFR <30 (Zometa). Hydrate well.

Hepatic

No dose adjustment required.

Clinical pearls

Once-yearly IV option — ideal for patients with GI intolerance of oral bisphosphonates or adherence issues
Acute phase reaction in ~40% after first dose — premedicate with paracetamol
HORIZON trial: zoledronic acid reduced hip fractures by 41% and mortality post-hip fracture
Hypocalcaemia prevention: ensure adequate calcium/Vit D before and after infusion
Dental review before starting — ONJ risk with oncology doses higher than osteoporosis doses

Contraindications

eGFR <35 (Aclasta) or <30 (Zometa)
Hypocalcaemia (correct before infusion)
Dehydration

Side effects

Acute phase reaction (flu-like: fever, myalgia, bone pain — 24–48 hours after first infusion; paracetamol)
Hypocalcaemia
Nephrotoxicity (infuse over minimum 15 min, ensure hydration)
Osteonecrosis of the jaw
Atypical femoral fractures (long-term)

Interactions

Aminoglycosides — additive nephrotoxicity
NSAIDs — additive nephrotoxicity risk
Calcium — do not co-infuse

Monitoring

eGFR and calcium (before each infusion)
Dental health annually
DEXA (after 3 years treatment)

Reference: BNFc; BNF; NICE CG146; HORIZON-PFT Trial; NOGG Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways