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Zoledronic Acid

Generic name: zoledronic acid systemic

Brand names: Zometa, Aclasta, Reclast

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Concentrate, Intravenous:

Generic: 4 mg/5 mL (5 mL)

Concentrate, Intravenous [preservative free]:

Zometa: 4 mg/5 mL (5 mL [DSC])

Generic: 4 mg/5 mL (5 mL)

Solution, Intravenous:

Zometa: 4 mg/100 mL (100 mL [DSC])

Generic: 4 mg/100 mL (100 mL)

Solution, Intravenous [preservative free]:

Reclast: 5 mg/100 mL (100 mL)

Generic: 4 mg/100 mL (100 mL); 5 mg/100 mL (100 mL)

Solution Reconstituted, Intravenous [preservative free]:

Generic: 4 mg (1 ea [DSC])


Mechanism of Action

Zoledronic acid is a bisphosphonate which inhibits bone resorption via actions on osteoclasts or on osteoclast precursors; it inhibits osteoclastic activity and skeletal calcium release induced by tumors. Decreases serum calcium and phosphorus, and increases their elimination. In osteoporosis, zoledronic acid inhibits osteoclast-mediated resorption, therefore reducing bone turnover.



Binds to bone


Primarily eliminated intact via the kidney; metabolism not likely


Urine (39% ± 16% as unchanged drug) within 24 hours; feces (<3%)

Half-Life Elimination

Triphasic; Terminal: 146 hours

Protein Binding

23% to 53%

Use in Specific Populations

Special Populations: Renal Function Impairment

Mild renal impairment (CrCl 50 to 80 mL/minute) increased AUC by an average of 15%. Moderate renal impairment (CrCl 30 to 50 mL/minute) increased AUC by an average of 43%. The risk of renal deterioration appears to increase with AUC, which doubled at a CrCl of 10 mL/minute.

Use: Labeled Indications

Bone metastases from solid tumors: Zometa: Treatment of documented bone metastases from solid tumors (in conjunction with standard antineoplastic therapy); prostate cancer should have progressed following treatment with at least one hormonal therapy.

Hypercalcemia of malignancy: Zometa: Treatment of hypercalcemia (albumin-corrected serum calcium ≥12 mg/dL) of malignancy.

Limitations of use: Safety and efficacy for treatment of hypercalcemia associated with hyperparathyroidism or with other non-tumor-related conditions have not been established.

Multiple myeloma: Zometa: Treatment of osteolytic lesions of multiple myeloma.

Osteoporosis: Reclast, Aclasta [Canadian product]: Treatment and prevention of osteoporosis in postmenopausal females; treatment to increase bone mass in males with osteoporosis; treatment and prevention of glucocorticoid-induced osteoporosis in males and females who are initiating or continuing systemic glucocorticoids with a prednisone dosage of ≥7.5 mg/day (or equivalent) and who are expected to remain on glucocorticoids for at least 12 months.

Paget disease: Reclast, Aclasta [Canadian product]: Treatment of Paget disease of bone in males and females. Note: Zoledronic acid is considered the most efficacious bisphosphonate with respect to treating bone pain as well as suppressing metabolic bone activity. In patients without contraindications, Endocrine Society guidelines as well as some international guidelines recommend zoledronic acid as the treatment of choice (Endocrine Society [Singer 2014]; Ralston 2019).

Use: Off Label

Breast cancer, early (adjuvant therapy)byes

A systematic review which included studies in women with early breast cancer demonstrated an advantage (reduced risk of bone metastases) with the adjuvant use of bisphosphonate therapy (including zoledronic acid) in postmenopausal females O'Carrigan 2017.

Based on the American Society of Clinical Oncology (ASCO) and Cancer Care Ontario (CCO) guidelines for the use of adjuvant bisphosphonates and other bone-modifying agents in breast cancer, zoledronic acid should be considered as adjuvant therapy for postmenopausal women (including females with natural menopause or induced by ovarian ablation/suppression) with nonmetastatic breast cancer who are candidates for adjuvant therapy.

Breast cancer, prevention of bone loss associated with aromatase inhibitor therapy in postmenopausal femalesa

Data from a randomized, 5-year, open-label, multicenter trial supports the use of zoledronic acid in the prevention of bone loss associated with aromatase inhibitor therapy in postmenopausal females with breast cancer Brufsky 2012.

Postrenal transplant bone loss (prevention)c

Therapy with zoledronic acid after kidney transplantation may provide short-term benefits in increasing the calcium content of cancellous bone. This initial therapy after transplantation was not shown to provide long-term effects and was not superior to placebo after 3 years post-transplant. Additional studies with a larger sample size must be completed to determine whether there is a benefit with zoledronic acid therapy following kidney transplantation Haas 2003, Schwarz 2004.

Prostate cancer, prevention of androgen deprivation therapy–associated osteoporosisa

Data from 2 randomized, placebo-controlled studies support the use of zoledronic acid (in conjunction with calcium and vitamin D supplementation) for the prevention of bone loss associated with androgen deprivation therapy in nonmetastatic prostate cancer Michaelson 2007, Smith 2003.


US labeling:

Hypersensitivity to zoledronic acid or any component of the formulation; hypocalcemia (Reclast only); CrCl <35 mL/minute and in those with evidence of acute renal impairment (Reclast only).

Canadian labeling:

All indications: Hypersensitivity to zoledronic acid or other bisphosphonates, or any component of the formulation; uncorrected hypocalcemia at the time of infusion; pregnancy, breast-feeding

Nononcology uses: Additional contraindications: Use in patients with CrCl <35 mL/minute and use in patients with evidence of acute renal impairment due to an increased risk of renal failure

Documentation of allergenic cross-reactivity for bisphosphonates is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.

Dosage and Administration

Dosing: Adult

Note: Acetaminophen administration after the infusion may reduce symptoms of acute-phase (influenza-like) reactions. Patients treated for bone metastases from solid tumors, multiple myeloma, and Paget disease should receive a daily calcium and vitamin D supplement, and patients with osteoporosis should receive calcium and vitamin D supplementation if dietary intake is inadequate.

Bone metastases from solid tumors (Zometa): IV: 4 mg once every 3 to 4 weeks.

Bone metastases due to breast cancer or prostate cancer (off-label dosing): IV: 4 mg once every 12 weeks; dosing once every 12 weeks (compared to once every 4 weeks) did not result in an increased risk of skeletal events within 2 years in patients with at least 1 site of bone involvement (Himmelstein 2017; Hortobagyi 2017).

Breast cancer, early, adjuvant therapy (off-label use): Postmenopausal females: IV: 4 mg once every 6 months for 3 to 5 years (ASCO [Dhesy-Thind 2017]).

Breast cancer, prevention of bone loss associated with aromatase inhibitor therapy (off-label use): Postmenopausal females: IV: 4 mg once every 6 months for 5 years (Brufsky 2012).

Hypercalcemia of malignancy (albumin-corrected serum calcium ≥12 mg/dL) (Zometa): IV: 4 mg (maximum) given as a single dose. Wait at least 7 days before considering re-treatment.

Multiple myeloma osteolytic lesions (Zometa): IV: 4 mg once every 3 to 4 weeks.

Lytic bone disease: American Society of Clinical Oncology (ASCO) guidelines: 4 mg once every 3 to 4 weeks for up to 2 years; less frequent dosing (eg, once every 3 months) may be considered in patients with stable/responsive disease; discontinue after 2 years in patients with responsive and/or stable disease; resume therapy upon relapse with new-onset skeletal-related events (ASCO [Anderson 2018]).

Multiple myeloma (off-label dosing): IV: 4 mg once every 12 weeks; dosing once every 12 weeks (compared to once every 4 weeks) did not result in an increased risk of skeletal events within 2 years in patients with at least 1 site of bone involvement (Himmelstein 2017).

Osteoporosis, prevention of fractures: Note: Prior to use, evaluate and treat any potential causes of secondary osteoporosis (eg, hypogonadism in males) (ES [Watts 2012].

High fracture risk patients, including those with a history of fragility fracture, or males ≥50 years of age and postmenopausal females with a T-score ≤−2.5, or a T-score between −1 and −2.5 at high fracture risk according to an assessment (ES [Eastell 2019]; NOF [Cosman 2014]; Siris 2014; Watts 2012):

Treatment (males and postmenopausal females): Reclast, Aclasta (Canadian product): IV: 5 mg once a year.

Patients with T-scores between −1 and −2.5 and not at high fracture risk; patient preferences may guide decision to initiate therapy (NOF [Cosman 2014]):

Prevention (postmenopausal females): IV: 5 mg once every 2 years (Reclast) or 5 mg as a single (one-time) dose (Aclasta [Canadian product]).

Note: Significant increase in bone mineral density of the lumbar spine, total hip, femoral neck and trochanter were observed at 2 years following a single 5 mg dose (McClung 2009). In another large randomized clinical trial, administration of 5 mg once every 18 months for up to 6 years significantly reduced the incidence of fragility fractures (nonvertebral [excluding hip] and vertebral) in osteopenic women with relatively high baseline fracture risk (Reid 2018).

Duration of therapy: The optimal duration of treatment has not been established. If fracture risk remains high (eg, fragility fracture before or during therapy) after the initial 3 years, consider extending therapy for up to 6 years or switching to alternative therapy (AACE/ACE [Camacho 2016]; Adler 2016; ES [Eastell 2019]; Watts 2010). Alternatively, if bone mineral density (BMD) is stable, there have been no previous fragility fractures, and short-term fracture risk is low, consider discontinuation (ie, drug holiday) after the initial 3 years. The optimal length of drug holiday has not been established, although it is usually for a period of up to 5 years (ES [Eastell 2019]). The decision to resume therapy after a drug holiday is based on multiple factors, including decline in BMD and risk factors for fracture (AACE/ACE [Camacho 2016]; Adler 2016; ES [Eastell 2019]).

Osteoporosis, glucocorticoid-induced (alternative agent): Note: Bisphosphonate therapy (preferably oral) is recommended for patients on glucocorticoid therapy at moderate to high risk of fracture. Avoid use in females who are pregnant, who plan on becoming pregnant, or who are not using effective birth control (ACR [Buckley 2017]).

Treatment and prevention (males and females): Reclast, Aclasta (Canadian product): IV: 5 mg once a year.

Paget disease (Reclast, Aclasta [Canadian product]): Note: For symptomatic patients with active disease and select patients with asymptomatic disease at risk of future complications; or prior to planned surgery at an active pagetic site (ES [Singer 2014]).

Initial: IV: 5 mg as a single dose.

Re-treatment: Re-treatment may be considered for patients who are symptomatic, or with inadequate initial response, or with evidence of biochemical relapse (eg, increase in alkaline phosphatase). Intensive re-treatment based on increased biochemical markers alone is not routinely recommended (Ralston 2019; Tan 2017). Re-treatment is seldom required within 5 years and suppression of biochemical markers up to 10 years has been reported with a single dose of zoledronic acid (Cundy 2017; Endocrine Society [Singer 2014]).

Postrenal transplant bone loss (prevention) (off-label use): IV: 4 mg at week 2 and month 3 after engraftment (Haas 2003; Schwarz 2004).

Prostate cancer, prevention of androgen deprivation therapy–associated osteoporosis (off-label use): IV: 4 mg once every 3 months for 1 year (Smith 2003) or 4 mg every 12 months (Michaelson 2007).

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Osteoporosis, primary or secondary: Limited data available: Note: Acetaminophen or ibuprofen 30 minutes prior to infusion and 6 hours after is recommended to reduce acute phase reactions (eg, flu-like symptoms including low-grade fever, nausea, myalgias, and fatigue).

Children <2 years (Bowden 2017):

First dose: IV: 0.0125 mg/kg/dose.

Maintenance (to begin 3 months after first dose): IV: 0.025 mg/kg/dose every 3 months.

Children ≥2 years and Adolescents (Bowden 2017; Munns 2007; Trejo 2016):

First dose: IV: 0.0125 mg/kg/dose.

Second dose (3 months after first dose): IV: 0.025 mg/kg/dose.

Maintenance (to begin 6 months after first dose): IV: 0.05 mg/kg/dose every 6 months; maximum dose: 4 mg/dose.

Dose adjustment based on lumbar spine bone mineral density (BMD) Z score: Children ≥2 years and Adolescents:

BMD Z score >−2: Decrease dose to 0.025 mg/kg/dose every 6 months.

BMD Z score >0: Decrease dose to 0.025 mg/kg/dose every 12 months.


Solution for injection:

Concentrate vials (4 mg/5 mL): Further dilute in 100 mL NS or D5W prior to administration.

Premixed bag (4 mg/100 mL): No further preparation is necessary. If reduced doses are required for patients with renal impairment, withdraw the specified volume of solution using an IV bag transfer device and discard withdrawn volume; label premixed bag with appropriate final drug content and final volume.

Ready-to-use bottles (4 mg/100 mL and 5 mg/100 mL): No further preparation is necessary. If reduced doses are required for patients with renal impairment, withdraw the appropriate volume of solution and replace with an equal amount of NS or D5W.


IV: If refrigerated, allow solution to reach room temperature before administration. Infuse over at least 15 minutes. Flush IV line with 10 mL NS flush following infusion. Infuse in a line separate from other medications. Patients must be appropriately hydrated prior to treatment. Acetaminophen after administration may reduce the incidence of acute reaction (eg, arthralgia, fever, flu-like symptoms, myalgia).

Multiple myeloma: If treatment is withheld for unexplained albuminuria, consider increasing the infusion time to at least 30 minutes upon reinitiation (ASCO [Anderson 2018]).

Dietary Considerations

Multiple myeloma or metastatic bone lesions from solid tumors: Take daily calcium supplement (500 mg) and daily multivitamin (with 400 units vitamin D).

Osteoporosis: Ensure adequate calcium and vitamin D intake; if dietary intake is inadequate, dietary supplementation is recommended. Males and females should consume:

Calcium: 1,000 mg/day (males: 50 to 70 years) or 1,200 mg/day (females ≥51 years and males ≥71 years) (IOM 2011; NOF [Cosman 2014]).

Vitamin D: 800 to 1,000 int. units/day (males and females ≥50 years) (NOF 2014). Recommended Dietary Allowance (RDA): 600 int. units/day (males and females ≤70 years) or 800 int. units/day (males and females ≥71 years) (IOM 2011).

Paget disease: Take elemental calcium 1,500 mg/day (750 mg twice daily or 500 mg 3 times/day) and vitamin D 800 units/day, particularly during the first 2 weeks after administration.


Solution for injection:

Aclasta [Canadian product]: Store at room temperature of 15°C to 30°C (59°F to 86°F). Keep sealed in original package until administration.

Reclast: Store at room temperature of 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). After opening, stable for 24 hours at 2°C to 8°C (36°F to 46°F). If refrigerated, allow the refrigerated solution to reach room temperature before administration.

Zoledronic acid 4 mg/100 mL premixed bag: Store at a temperature of ≤30°C (86°F); protect from freezing.

Zometa: Store concentrate vials and ready-to-use bottles at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Diluted solutions for infusion in D5W or NS which are not used immediately after preparation should be refrigerated at 2°C to 8°C (36°F to 46°F). Infusion of solution must be completed within 24 hours of preparation. The ready-to-use bottles are for single use only; if any preparation is necessary (preparing reduced dosage for patients with renal impairment), the prepared, diluted solution may be refrigerated at 2°C to 8°C (36°F to 46°F) if not used immediately. Infusion of solution must be completed within 24 hours of preparation. The previously withdrawn volume from the ready-to-use solution should be discarded; do not store or reuse.

Drug Interactions

Aminoglycosides: May enhance the hypocalcemic effect of Bisphosphonate Derivatives. Monitor therapy

Angiogenesis Inhibitors (Systemic): May enhance the adverse/toxic effect of Bisphosphonate Derivatives. Specifically, the risk for osteonecrosis of the jaw may be increased. Monitor therapy

Calcitonin: May enhance the hypocalcemic effect of Zoledronic Acid. Monitor therapy

Deferasirox: Bisphosphonate Derivatives may enhance the adverse/toxic effect of Deferasirox. Specifically, the risk for GI ulceration/irritation or GI bleeding may be increased. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: May enhance the adverse/toxic effect of Bisphosphonate Derivatives. Both an increased risk of gastrointestinal ulceration and an increased risk of nephrotoxicity are of concern. Monitor therapy

Proton Pump Inhibitors: May diminish the therapeutic effect of Bisphosphonate Derivatives. Monitor therapy

Thalidomide: May enhance the adverse/toxic effect of Zoledronic Acid. Monitor therapy

Test Interactions

Bisphosphonates may interfere with diagnostic imaging agents such as technetium-99m-diphosphonate in bone scans.

Adverse Reactions

Oncology indications:


Cardiovascular: Lower extremity edema (5% to 21%), hypotension (11%)

Central nervous system: Fatigue (39%), headache (5% to 19%), dizziness (18%), insomnia (15% to 16%), depression (14%), anxiety (11% to 14%), agitation (13%), confusion (7% to 13%), hypoesthesia (12%), rigors (11%)

Dermatologic: Alopecia (12%), dermatitis (11%)

Endocrine & metabolic: Dehydration (5% to 14%), hypophosphatemia (13%), hypokalemia (12%), hypomagnesemia (11%)

Gastrointestinal: Nausea (29% to 46%), vomiting (14% to 32%), constipation (27% to 31%), diarrhea (17% to 24%), anorexia (9% to 22%), weight loss (16%), abdominal pain (14% to 16%), decreased appetite (13%)

Genitourinary: Urinary tract infection (12% to 14%)

Hematologic & oncologic: Anemia (22% to 33%), progression of cancer (16% to 20%), neutropenia (12%)

Infection: Candidiasis (12%)

Neuromuscular & skeletal: Ostealgia (55%), weakness (5% to 24%), myalgia (23%), arthralgia (5% to 21%), back pain (15%), paresthesia (15%), limb pain (14%), skeletal pain (12%)

Renal: Renal insufficiency (8% to 17%; up to 40% in patients with abnormal baseline creatinine)

Respiratory: Dyspnea (22% to 27%), cough (12% to 22%)

Miscellaneous: Fever (32% to 44%; most common symptom of acute phase reaction)

1% to 10%:

Cardiovascular: Chest pain (5% to 10%)

Central nervous system: Somnolence (5% to 10%)

Endocrine & metabolic: Hypocalcemia (5% to 10%; grades 3/4: ≤1%), hypermagnesemia (grade 3: 2%)

Gastrointestinal: Dyspepsia (10%), dysphagia (5% to 10%), mucositis (5% to 10%), sore throat (8%), stomatitis (8%)

Hematologic & oncologic: Granulocytopenia (5% to 10%), pancytopenia (5% to 10%), thrombocytopenia (5% to 10%)

Infection: Infection (nonspecific; 5% to 10%)

Renal: Increased serum creatinine (grades 3/4: ≤2%)

Respiratory: Upper respiratory tract infection (10%)

Nononcology indications:


Cardiovascular: Hypertension (5% to 13%)

Central nervous system: Pain (2% to 24%), fever (9% to 22%), headache (4% to 20%), chills (2% to 18%), fatigue (2% to 18%), flank pain (≤2%)

Endocrine & metabolic: Hypocalcemia (≤3%; Paget disease 21%), dehydration (3%)

Gastrointestinal: Nausea (5% to 18%), upper abdominal pain (5%), abdominal distension (≤2%)

Immunologic: Infusion-related reaction (4% to 25%)

Neuromuscular & skeletal: Arthralgia (9% to 27%), myalgia (5% to 23%), back pain (4% to 18%), limb pain (3% to 16%), musculoskeletal pain (≤12%), osteoarthritis (6%)

Respiratory: Flu-like symptoms (1% to 11%)

1% to 10%:

Cardiovascular: Chest pain (1% to 8%), peripheral edema (3% to 6%), atrial fibrillation (1% to 3%), palpitations (≤3%)

Central nervous system: Dizziness (2% to 9%), rigors (8%), malaise (1% to 7%), hypoesthesia (≤6%), lethargy (3% to 5%), vertigo (1% to 4%), paresthesia (2%), hyperthermia (≤2%)

Dermatologic: Skin rash (2% to 3%), hyperhidrosis (≤3%)

Gastrointestinal: Abdominal pain (1% to 9%), diarrhea (5% to 8%), vomiting (2% to 8%), constipation (6% to 7%), dyspepsia (2% to 7%), abdominal discomfort (1% to 2%), anorexia (1% to 2%)

Hematologic & oncologic: Change in serum protein (C-reactive protein increased; ≤5%)

Neuromuscular & skeletal: Ostealgia (3% to 9%), arthritis (2% to 9%), neck pain (1% to 7%), shoulder pain (≤7%), muscle spasm (2% to 6%), weakness (2% to 6%), stiffness (1% to 5%), jaw pain (2% to 4%), joint swelling (≤3%)

Ophthalmic: Eye pain (≤2%)

Renal: Increased serum creatinine (2%)

Respiratory: Dyspnea (5% to 7%)

All indications: <1%, postmarketing, and/or case reports: Acute phase reaction-like symptoms (including pyrexia, fatigue, bone pain, arthralgia, myalgia, chills, influenza-like illness; usually resolves within 3 to 4 days of onset, although may take up to 14 days to resolve), acute renal failure (requiring hospitalization/dialysis), acute renal tubular necrosis (toxic), anaphylactic shock, anaphylaxis, angioedema, arthralgia (sometimes severe and/or incapacitating), blurred vision, bradycardia, bronchoconstriction, bronchospasm, cardiac arrhythmia, cerebrovascular accident, conjunctivitis, diaphoresis, drowsiness, dysgeusia, episcleritis, exacerbation of asthma, Fanconi syndrome (acquired), femur fracture (diaphyseal or subtrochanteric), hematuria, hyperesthesia, hyperkalemia, hypernatremia, hyperparathyroidism, hypersensitivity reaction, hypertension, injection site reaction (eg, itching, pain, redness), interstitial pulmonary disease, iridocyclitis, iritis, muscle cramps, myalgia (sometimes severe and/or incapacitating), numbness, osteonecrosis (including external auditory canal, femur, and hip), osteonecrosis of the jaw, periorbital edema, periorbital swelling, prolonged QT interval on ECG, proteinuria, pruritus, renal insufficiency, scleritis, seizure, skin rash, Stevens-Johnson syndrome, tetany, toxic epidermal necrolysis, tremor, urticaria, uveitis, weight gain, xerostomia


Concerns related to adverse effects:

  • Bone fractures: Atypical femur fractures (AFF) have been reported in patients receiving bisphosphonates. The fractures include subtrochanteric femur (bone just below the hip joint) and diaphyseal femur (long segment of the thigh bone). Some patients experience prodromal pain weeks or months before the fracture occurs. It is unclear if bisphosphonate therapy is the cause for these fractures; AFFs have also been reported in patients not taking bisphosphonates, and in patients receiving glucocorticoids. Patients receiving long-term (>3 to 5 years) bisphosphonate therapy may be at an increased risk (Adler 2016; NOF [Cosman 2014]); however, benefits of therapy (when used for osteoporosis) generally outweigh absolute risk of AFF within the first 5 years of treatment, especially in patients with high fracture risk (Adler 2016; ES [Eastell 2019]). Patients presenting with thigh or groin pain with a history of receiving bisphosphonates should be evaluated for femur fracture. Consider interrupting bisphosphonate therapy in patients who develop a femoral shaft fracture; assess for fracture in the contralateral limb.
  • Hypersensitivity reactions: Rare cases of urticaria and angioedema and very rare cases of anaphylactic reactions/shock have been reported.
  • Hypocalcemia: Hypocalcemia (including severe and life-threatening cases) has been reported with use; patients with Paget disease may be at significant risk for hypocalcemia after treatment with zoledronic acid (because pretreatment rate of bone turnover may be elevated); severe and life-threatening hypocalcemia has also been reported with oncology-related uses. Measure serum calcium prior to treatment initiation. Correct preexisting hypocalcemia before initiation of therapy in patients with Paget disease, osteoporosis, or oncology indications. Use with caution with other medications known to cause hypocalcemia (severe hypocalcemia may develop). Ensure adequate calcium and vitamin D supplementation during therapy. Use caution in patients with disturbances of calcium and mineral metabolism (eg, hypoparathyroidism, thyroid/parathyroid surgery, malabsorption syndromes, excision of small intestine). QTc prolongation, cardiac arrhythmias, and neurologic events (eg, tetany, tonic-clonic seizures, numbness) secondary to severe hypocalcemia have been reported 1 day to several months after initiation of therapy.
  • Influenza-like illness/acute phase reaction: A transient acute phase reaction (eg, fever, chills, pain/myalgia, other influenza-like symptoms) may occur, typically within 3 days following the initial infusion; resolution is usually observed ~3 days after symptom onset but can take up to 14 days. Prophylactic use of acetaminophen may reduce symptoms. The incidence of symptoms may decrease with subsequent infusions.
  • Musculoskeletal pain: Severe (and occasionally debilitating) bone, joint, and/or muscle pain have been reported during bisphosphonate treatment. The onset of pain ranged from a single day to several months. Consider discontinuing therapy in patients who experience severe symptoms; symptoms usually resolve upon discontinuation. Some patients experienced recurrence when rechallenged with the same drug or another bisphosphonate; avoid use in patients with a history of these symptoms in association with bisphosphonate therapy.
  • Ocular effects: Conjunctivitis, uveitis, episcleritis, iritis, scleritis, and orbital inflammation have been reported with zoledronic acid; patients presenting with signs of ocular inflammation may require further ophthalmologic evaluation. Ocular symptoms resolved with topical steroids in some cases.
  • Osteonecrosis of the jaw: Osteonecrosis of the jaw (ONJ), also referred to as medication-related osteonecrosis of the jaw (MRONJ), has been reported in patients receiving bisphosphonates. Known risk factors for MRONJ include invasive dental procedures (eg, tooth extraction, dental implants, bony surgery), cancer diagnosis, concomitant therapy (eg, chemotherapy, corticosteroids, angiogenesis inhibitors), poor oral hygiene, ill-fitting dentures, and comorbid disorders (anemia, coagulopathy, infection, preexisting dental disease). Risk may increase with duration of bisphosphonate use and/or may be reported at a greater frequency based on tumor type (eg, advanced breast cancer or multiple myeloma). According to a position paper by the American Association of Maxillofacial Surgeons (AAOMS), MRONJ has been associated with bisphosphonates and other antiresorptive agents (denosumab), and antiangiogenic agents (eg, bevacizumab, sunitinib) used for the treatment of osteoporosis or malignancy; risk is significantly higher in cancer patients receiving antiresorptive therapy compared to patients receiving osteoporosis treatment (regardless of medication used or dosing schedule). MRONJ risk is also increased with monthly IV antiresorptive therapy compared to the minimal risk associated with oral bisphosphonate use, although risk appears to increase with oral bisphosphonates when duration of therapy exceeds 4 years. The manufacturer's labeling states that there are no data to suggest whether discontinuing bisphosphonates in patients requiring invasive dental procedures reduces the risk of ONJ. The manufacturer recommends a dental exam and preventive dentistry be performed prior to placing patients with risk factors on chronic bisphosphonate therapy and that during therapy, invasive dental procedures be avoided, if possible. The AAOMS suggests that if medically permissible, initiation of IV bisphosphonates for cancer therapy should be delayed until optimal dental health is attained (if extractions are required, antiresorptive therapy should delayed until the extraction site has mucosalized or until after adequate osseous healing). Once IV bisphosphonate therapy is initiated for oncologic disease, procedures that involve direct osseous injury and placement of dental implants be avoided. Patients developing ONJ during therapy should receive care by an oral surgeon (AAOMS [Ruggiero 2014]).

Disease-related concerns:

  • Aspirin-sensitive asthma: Use with caution in patients with aspirin-sensitive asthma; may cause bronchoconstriction.
  • Breast cancer (metastatic): The American Society of Clinical Oncology (ASCO)/Cancer Care Ontario (CCO) has updated guidelines on the role of bone-modifying agents (BMAs) in metastatic breast cancer patients (ASCO/CCO [Van Poznak 2017]). The guidelines recommend initiating a BMA (denosumab, pamidronate, zoledronic acid) in patients with metastatic breast cancer to the bone. One BMA is not recommended over another (evidence supporting one BMA over another is insufficient). The optimal duration of BMA therapy is not defined; however, the guidelines recommend continuing BMA therapy indefinitely. The analgesic effect of BMAs are modest and BMAs should not be used alone for pain management; supportive care, analgesics, adjunctive therapies, radiation therapy, surgery, and/or systemic anticancer therapy should be utilized. The ASCO/CCO guidelines are in alignment with prescribing information for dosing, renal dose adjustments, infusion times, prevention and management of osteonecrosis of the jaw, and monitoring of laboratory parameter recommendations. BMAs are not the first-line therapy for pain.
  • Multiple myeloma: The American Society of Clinical Oncology (ASCO) has updated guidelines on bone modifying agents in multiple myeloma (ASCO [Anderson 2018]). Bisphosphonate (pamidronate or zoledronic acid) therapy should be initiated in patients with radiographic or imaging evidence of lytic bone disease. Bisphosphonates may also be considered in patients with pain secondary to osteolytic disease and as adjunct therapy in patients receiving other interventions for fractures or impending fractures. The guidelines support utilizing IV bisphosphonates in patients with multiple myeloma and osteopenia (osteoporosis) but no radiographic evidence of lytic bone disease. Bisphosphonates are not recommended in patients with solitary plasmacytoma, smoldering (asymptomatic) or indolent myeloma with osteopenia in the absence of lytic bone disease. Bisphosphonates are also not recommended in monoclonal gammopathy of undetermined significance unless osteopenia (osteoporosis) also is present. The guidelines recommend monthly treatment for a period of up to 2 years (less frequent dosing may be considered in patients with stable/responsive disease). After 2 years, consider discontinuing in responsive and stable patients, and reinitiate upon relapse if a new-onset skeletal-related event occurs. The ASCO guidelines are in alignment with prescribing information for dosing, renal dose adjustments, infusion times, prevention and management of osteonecrosis of the jaw, and monitoring of laboratory parameter recommendations. According to the guidelines, in patients with a serum creatinine >3 mg/dL or CrCl <30 mL/minute or extensive bone disease, an alternative bisphosphonate (pamidronate) should be used. Monitor for albuminuria every 3 to 6 months; in patients with unexplained albuminuria >500 mg/24 hours, withhold the dose until level returns to baseline, then recheck every 3 to 4 weeks. Upon reinitiation, the guidelines recommend considering increasing the zoledronic acid infusion time to at least 30 minutes; however, one study has demonstrated that extending the infusion to 30 minutes did not change the safety profile (Berenson 2011).
  • Osteoporosis in survivors of adult cancers (nonmetastatic disease): Survivors of adult cancers with nonmetastatic disease who have osteoporosis (T score of -2.5 or lower in femoral neck, total hip, or lumbar spine) or who are at increased risk of osteoporotic fractures, should be offered bone-modifying agents (utilizing the osteoporosis-indicated dose) to reduce the risk of fracture. For patients without hormonal responsive cancers, when clinically appropriate, estrogens may be administered along with other bone-modifying agents (ASCO [Shapiro 2019]). The choice of bone-modifying agent (eg, oral or IV bisphosphonates or subcutaneous denosumab) should be based on several factors (eg, patient preference, potential adverse effects, quality of life considerations, availability, adherence, cost). Adequate calcium and vitamin D intake, exercise (using a combination of exercise types), as well as lifestyle modifications (if indicated) should also be encouraged.
  • Renal impairment: Use with caution in mild to moderate renal impairment. Single and multiple infusions in patients with both normal and impaired renal function have been associated with renal deterioration, resulting in renal failure and dialysis (rare). Preexisting renal compromise, severe dehydration, and concurrent use with diuretics or other nephrotoxic drugs may increase the risk for renal impairment. Adequate hydration is required during treatment (urine output ~2 L/day); avoid overhydration, especially in patients with heart failure.

Nononcology indications: Use is contraindicated in patients with CrCl <35 mL/minute and in patients with evidence of acute renal impairment. Do not use single doses >5 mg and do not infuse over less than 15 minutes. Patients with underlying moderate to severe renal impairment, increased age, concurrent use of nephrotoxic or diuretic medications, or severe dehydration prior to or after zoledronic acid administration may have an increased risk of acute renal impairment or renal failure. Others with increased risk include patients with renal impairment or dehydration secondary to fever, sepsis, gastrointestinal losses, or diuretic use. If history or physical exam suggests dehydration, treatment should not be given until the patient is normovolemic. Obtain serum creatinine and calculate creatinine clearance (using actual body weight) with the Cockcroft-Gault formula prior to each administration. Transient increases in serum creatinine may be more pronounced in patients with impaired renal function; monitoring creatinine clearance in at-risk patients taking other renally eliminated drugs is recommended.

Oncology indications: Dosage adjustment required with renal impairment. Use is not recommended in patients with severe renal impairment (serum creatinine >3 mg/dL or CrCl <30 mL/minute) and bone metastases (limited data); use in patients with hypercalcemia of malignancy and severe renal impairment (serum creatinine >4.5 mg/dL for hypercalcemia of malignancy) should only be done if the benefits outweigh the risks. In cancer patients, do not use single doses >4 mg and do not infuse over less than 15 minutes (renal toxicity has been reported with doses >4 mg or infusions administered over less than 15 minutes). Risk factors for renal deterioration include preexisting renal insufficiency and repeated doses and other bisphosphonates therapy. Dehydration and the use of other nephrotoxic drugs which may contribute to renal deterioration should be identified and managed. Diuretics should not be used before correcting hypovolemia. Assess renal function (eg, serum creatinine) prior to each dose and withhold for renal deterioration (increase in serum creatinine of 0.5 mg/dL [if baseline level normal] or increase of 1 mg/dL [if baseline level abnormal]); treatment should be withheld until renal function returns to within 10% of baseline.

Special populations:

  • Elderly: Because decreased renal function occurs more commonly in elderly patients, take special care to monitor renal function.

Other warnings/precautions:

  • Duplicate therapy: Do not administer Zometa and Reclast (Aclasta [Canadian product]) to the same patient for different indications.

Monitoring Parameters

Prior to initiation of therapy, dental exam and preventive dentistry for patients at risk for osteonecrosis, including all cancer patients. Evaluate pregnancy status prior to use.

Nononcology uses: Serum creatinine prior to each dose, especially in patients with risk factors, calculate creatinine clearance before each treatment (consider interim monitoring in patients at risk for acute renal failure), evaluate fluid status and adequately hydrate patients prior to and following administration.

Osteoporosis: Serial bone mineral density (BMD) should be evaluated at baseline and every 1 to 3 years on treatment (usually at ~2 years following initiation of therapy, then more or less frequently depending on patient-specific factors and stability of BMD) (AACE/ACE [Camacho 2016]; ES [Eastell 2019]; NOF [Cosman 2014]); evaluate BMD every 2 to 4 years during a drug holiday (ES [Eastell 2019]); in patients with combined zoledronic acid and glucocorticoid treatment, evaluate BMD at initiation of glucocorticoid therapy and after 6 to 12 months, then every 2 to 3 years if patient continues to have significant osteoporosis risk factors (ACR [Buckley 2017]); serum calcium and 25(OH)D; annual measurements of height and weight, assessment of chronic back pain; phosphorus and magnesium; may consider monitoring biochemical markers of bone turnover (eg, fasting serum CTX or urinary NTX) at baseline, 3 months, and 6 months, to assess treatment response (ES [Eastell 2019]).

Paget disease: Serum total alkaline phosphatase at 6 to 12 weeks for initial response to treatment (when bone turnover will have shown a substantial decline) and potentially at 6 months (maximal suppression of high bone turnover); following treatment completion, monitor at ~1- to 2-year intervals (Endocrine Society [Singer 2014]); monitoring more specific biochemical markers of bone turnover (eg, serum P1NP, NTX, serum beta-CTx) is generally only warranted in patients with Paget disease who have abnormal liver or biliary tract function or when early assessment of response to treatment is needed (eg, spinal compression, very active disease) (Endocrine Society [Singer 2014]); serum calcium and 25(OH)D; phosphorus and magnesium; symptoms of hypocalcemia, pain (posttreatment pain may not strictly correlate with increased biochemical markers [Ralston 2019]).

Oncology uses: Serum creatinine prior to each dose; serum electrolytes, phosphate, magnesium, and hemoglobin/hematocrit should be evaluated regularly. Monitor serum calcium to assess response and avoid overtreatment. In patients with multiple myeloma, monitor urine every 3 to 6 months for albuminuria.

Multiple myeloma: Monitor serum creatinine (prior to each dose), serum calcium (regularly); vitamin D levels (intermittently), spot urine sample for albuminuria (every 3 to 6 months; for unexplained albuminuria, obtain 24 urine collection to assess urinary albumin; reassess every 3 to 4 weeks with 24-hour urine collection for total protein and urine protein electrophoresis until renal function returns to baseline) (ASCO [Anderson 2018]).


Pregnancy Considerations

It is not known if bisphosphonates cross the placenta, but fetal exposure is expected (Djokanovic 2008; Stathopoulos 2011).

Information specific to zoledronic acid exposure during pregnancy is limited (Djokanovic 2008; Richa 2018). Bisphosphonates are incorporated into the bone matrix and gradually released over time. The amount available in the systemic circulation varies by dose and duration of therapy. Theoretically, there may be a risk of fetal harm when pregnancy follows the completion of therapy; however, available data have not shown that exposure to bisphosphonates during pregnancy significantly increases the risk of adverse fetal events (Djokanovic 2008; Green 2014; Levy 2009; Sokol 2019; Stathopoulos 2011). Because hypocalcemia has been described following in utero bisphosphonate exposure, exposed infants should be monitored for hypocalcemia after birth (Djokanovic 2008; Stathopoulos 2011).

Until additional data are available, most sources recommend discontinuing bisphosphonate therapy in females of reproductive potential as early as possible prior to a planned pregnancy. Use of bisphosphonates in premenopausal females should be reserved for special circumstances when rapid bone loss is occurring; a bisphosphonate with the shortest half-life should be then used (Bhalla 2010; Pereira 2012; Stathopoulos 2011). Oral bisphosphonates can be considered for the prevention of glucocorticoid-induced osteoporosis in premenopausal females with moderate to high risk of fracture who do not plan to become pregnant during the treatment period and are using effective birth control (or are not sexually active); intravenous therapy should be reserved for high risk patients only (Buckley [ACR 2017]).

Evaluate pregnancy status prior to use. Females of reproductive potential should use effective contraception during and after treatment with zoledronic acid.

Patient Education

What is this drug used for?

  • It is used to treat high calcium levels in patients with cancer.
  • It is used when treating some cancers.
  • It is used to treat Paget's disease.
  • It is used to prevent or treat soft, brittle bones (osteoporosis).
  • It may be given to you for other reasons. Talk with the doctor.

Frequently reported side effects of this drug

  • Dizziness
  • Nausea
  • Vomiting
  • Abdominal pain
  • Heartburn
  • Flu-like symptoms
  • Diarrhea
  • Back pain
  • Neck pain
  • Painful extremities
  • Anxiety
  • Hair loss
  • Trouble sleeping
  • Lack of appetite
  • Constipation
  • Cough
  • Weight loss

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

  • Fluid and electrolyte problems like mood changes, confusion, muscle pain or weakness, abnormal heartbeat, severe dizziness, passing out, fast heartbeat, increased thirst, seizures, loss of strength and energy, lack of appetite, unable to pass urine or change in amount of urine passed, dry mouth, dry eyes, or nausea or vomiting.
  • Urinary tract infection like blood in the urine, burning or painful urination, passing a lot of urine, fever, lower abdominal pain, or pelvic pain.
  • Kidney problems like unable to pass urine, blood in the urine, change in amount of urine passed, or weight gain.
  • Severe bone pain
  • Severe joint pain
  • Severe muscle pain
  • Groin, hip, or thigh pain
  • Agitation
  • Shortness of breath
  • Burning or numbness feeling
  • Depression
  • Chest pain
  • Vision changes
  • Eye pain
  • Severe eye irritation
  • Mouth sores
  • Difficulty swallowing
  • Severe pain with swallowing
  • Chills
  • Sore throat
  • Bruising
  • Bleeding
  • Severe loss of strength and energy
  • Severe headache
  • Swelling of arms or legs
  • Vaginal pain, itching, and discharge
  • Jaw pain or edema
  • Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated January 31, 2020.