Zoledronic acid

Bisphosphonates
Bisphosphonates

The most potent bisphosphonate, given as an intravenous infusion for hypercalcaemia of malignancy, bone metastases, myeloma and osteoporosis.

Updated Nov 1, 2026

Also called: Zoledronate

Quick facts

Group: Bisphosphonates
Target: Farnesyl pyrophosphate synthase (FPPS), an enzyme of the mevalonate pathway in osteoclasts
Used for: Hypercalcaemia of malignancy · Multiple myeloma
Key effects: Acute-phase reaction in the first days · Nausea
Monitor: Serum creatinine before each dose · Calcium
ATC: M05BA08

No doses: the clinician sets them by the current guideline.

Mechanism of action

Farnesyl pyrophosphate synthase (FPPS), an enzyme of the mevalonate pathway in osteoclastsZoledronic acid

The figure shows zoledronic acid itself in the active site of human farnesyl pyrophosphate synthase, with magnesium ions and the substrate isopentenyl diphosphate.

Target in 3D: Farnesyl pyrophosphate synthase (FPPS), an enzyme of the mevalonate pathway in osteoclasts. PDB structure 1ZW5 (RCSB PDB, public domain). View the structure at RCSB PDB

Zoledronic acid is a nitrogen-containing bisphosphonate with an imidazole ring. It binds avidly to bone mineral, enters osteoclasts and inhibits farnesyl pyrophosphate synthase, so osteoclasts stop resorbing bone. In cancer this lowers the calcium that tumours release from bone and reduces skeletal events; in osteoporosis an infusion keeps resorption suppressed for a long time.

The infusion delivers zoledronic acid straight to bone mineral
Osteoclasts take it up during resorption
It blocks farnesyl pyrophosphate synthase in the osteoclast
Resorption falls: serum calcium drops and bone is protected

Indications

Hypercalcaemia of malignancy Hypercalcaemia of malignancy →
Multiple myeloma and bone metastases from solid tumours (with cancer treatment) Multiple myeloma →
Osteoporosis (infusion at long intervals) Osteoporosis →
Paget disease of bone Paget disease of bone →

Adverse effects

Common

Acute-phase reaction in the first days: fever, chills, headache, bone and muscle pain
Nausea, vomiting, loss of appetite
Fatigue
Pain or swelling at the infusion site
Eye redness or inflammation

Contraindications

Hypersensitivity to zoledronic acid or other components
Uncorrected hypocalcaemia
Not recommended with severe kidney impairment
Not combined with another product that contains zoledronic acid or another bisphosphonate

Key interactions

Aminoglycosides and calcitonin: Additive, prolonged fall in serum calcium
Loop diuretics: More risk of hypocalcaemia; they are not used before the person is rehydrated
Other nephrotoxic drugs (e.g. NSAIDs): More kidney damage

What is monitored

Serum creatinine before each dose
Calcium, phosphate and magnesium
Hydration status
Dental examination before starting
Thigh or groin pain

Administration and safety

Given only as an intravenous infusion by staff, never as a rapid push, over the time the label states
Uses its own line and is not mixed with solutions that contain calcium or other divalent cations
The person is well hydrated before the infusion
Oncology and osteoporosis products have different strengths and schedules; check which one is ordered (same active ingredient)

Pregnancy and breastfeeding

Can harm the fetus; pregnancy is ruled out before treatment, and because the drug stays in bone the risk may persist after the last dose.

Nursing care

Check creatinine and calcium before the infusion; report abnormal results
Encourage fluids before the dose as ordered and watch urine output
Explain the flu-like reaction of the first days; report fever that lasts or severe pain
Ask about dental work and teach good oral hygiene
Watch for numbness, tingling or cramps (hypocalcaemia)

Pharmacokinetics

Absorption: Given only intravenously
Distribution: A large part binds bone and is released slowly
Metabolism: Not metabolised and does not affect CYP enzymes
Elimination: Unchanged by the kidney; clearance falls with kidney function

Test yourself

Think of the answer, then tap the question to see it.

What must be checked before every dose of zoledronic acid?

Serum creatinine (it is cleared unchanged by the kidney and can damage it), plus calcium and hydration.

What is the acute-phase reaction after zoledronic acid?

Fever, chills, headache and bone or muscle pain in the first days after an infusion, usually self-limited.

Why are loop diuretics delayed until a person with hypercalcaemia is rehydrated?

Given to a dehydrated person they worsen volume depletion and kidney function; after rehydration they also add to the risk of hypocalcaemia with zoledronic acid.

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Connections

← Back to the class: Bisphosphonates

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: Zoledronic Acid Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); DailyMed - ZOLEDRONIC ACID injection (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).

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Representative model, for educational purposes only.