zoledronic acid
Brand: Zometa, Reclast
Prototype: alendronate
Drug Class: bisphosphonate
Drug Family: bone agent
Subclass: most potent nitrogen-containing bisphosphonate (IV)
Organ Systems: endocrinemusculoskeletalhematology-oncology
Mechanism of Action
Most potent bisphosphonate available; IV administration delivers drug directly to the bloodstream and to bone. Inhibits FPPS in osteoclasts with very high potency, reducing bone resorption. Oncologic use (Zometa) at higher doses every 3–4 weeks for skeletal-related events in cancer; osteoporosis use (Reclast) once yearly.
farnesyl pyrophosphate synthase (FPPS) in osteoclasts
Indications
- osteoporosis (Reclast: 5 mg IV once yearly)
- Paget's disease of bone
- malignant hypercalcemia
- bone metastases prevention (Zometa: multiple myeloma, solid tumors)
- glucocorticoid-induced osteoporosis
Contraindications
- acute renal impairment (CrCl <35 mL/min for osteoporosis; <30–35 for oncology)
- hypocalcemia
- hypersensitivity
Adverse Effects
Common
- acute phase reaction (fever, myalgia, arthralgia, flu-like symptoms within 1–3 days of first infusion)
- nausea
- fatigue
Serious
- osteonecrosis of the jaw (higher risk in oncologic doses)
- atypical femoral fracture
- acute renal tubular injury
- hypocalcemia (severe)
Pharmacokinetics (ADME)
| Absorption | IV infusion; no oral form |
| Distribution | rapid distribution to bone; binds to bone mineral |
| Metabolism | not metabolized |
| Excretion | renal (39% within 24 hours) |
| Half-life | 167 hours (plasma); >10 years in bone |
| Onset | within days |
| Peak | end of infusion |
| Duration | years (once yearly dosing for osteoporosis) |
| Protein Binding | 22% |
| Vd | bone |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| nephrotoxic agents | additive renal toxicity risk | major |
| calcium/vitamin D supplementation | supplementation is required to prevent hypocalcemia post-infusion | beneficial |
Nursing Considerations
- Administer IV over 15 minutes (minimum); check renal function before every dose — do not administer if CrCl <35 mL/min (osteoporosis) or rising creatinine.
- Pre-hydrate patient; ensure patient is taking calcium (1000–1200 mg/day) and vitamin D (400–800 IU/day) before and after infusion to prevent hypocalcemia.
- Warn patient about acute phase reaction after first infusion: fever, myalgia, and flu-like symptoms lasting 1–3 days; acetaminophen or ibuprofen can be taken prophylactically.
- Assess dental health and ensure any invasive dental work is completed before initiating therapy; ONJ risk is higher in oncology doses.
Clinical Pearls
- Annual IV zoledronic acid for osteoporosis (Reclast 5 mg) dramatically improves adherence compared to daily or weekly oral bisphosphonates, and is the only IV osteoporosis bisphosphonate with demonstrated mortality reduction post-hip fracture.
- Malignant hypercalcemia is the oncologic emergency indication: IV zoledronic acid works within 2–4 days and provides longer normocalcemia than pamidronate.
Safety Profile
Pregnancy avoid
Lactation avoid
Renal Adjustment Required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
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