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Bisphosphonate Pregnancy: D — contraindicated

Zoledronic Acid

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

Adult dose

Dose: Osteoporosis: 5mg IV once yearly. Oncology (bone mets): 4mg IV every 3–4 weeks
Route: Intravenous infusion
Frequency: Once yearly (osteoporosis) or every 3–4 weeks (oncology)
Infuse over minimum 15 minutes. Pre-hydrate with 500mL saline before infusion. Not for use if eGFR <35 mL/min (Aclasta) or <30 (Zometa).

Clinical pearls

  • Dental assessment BEFORE starting — ONJ risk significantly higher with poor dental hygiene
  • Acute phase reaction ("flu-like" first dose): manage with paracetamol and ibuprofen prophylactically
  • Give calcium 1000mg + vitamin D 800 units daily alongside zoledronic acid
  • Osteoporosis treatment holiday after 3–5 years — reassess with DEXA
  • Single annual infusion — major adherence advantage over weekly oral bisphosphonates

Contraindications

  • eGFR <35 mL/min
  • Hypocalcaemia (correct before infusion)
  • Pregnancy
  • Dental work planned within 3 months

Side effects

  • Acute phase reaction: fever, myalgia, arthralgia (24–72h post-infusion)
  • Osteonecrosis of the jaw (ONJ)
  • Atypical femoral fracture (long-term)
  • AKI (rapid infusion)
  • Uveitis

Interactions

  • Aminoglycosides — additive hypocalcaemia
  • NSAIDs — increased renal toxicity risk
  • Loop diuretics — additive hypocalcaemia

Monitoring

  • Renal function (creatinine before each infusion)
  • Serum calcium and phosphate before infusion
  • DEXA scan every 1–2 years
  • Dental review annually

Reference: NOGG Osteoporosis Guidelines 2021; NICE TA160. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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