Zoledronic acid belongs to the family of medications known as bisphosphonates. It is used to treat Paget's disease of the bone. It is also used to treat osteoporosis, to prevent osteoporosis in postmenopausal people, and to treat and prevent osteoporosis caused by steroid medications.

Normally, the body maintains a balance between the processes of breaking down bone and building it up. In Paget's disease and osteoporosis, this balance becomes disturbed so that too much bone is being broken down. Zoledronic acid works by restoring the balance between the rate of bone breakdown and buildup.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop receiving this medication without consulting your doctor.

For Paget's disease and for the prevention of osteoporosis in postmenopausal people, the recommended dose of zoledronic acid is 5 mg given as a one-time intravenous (into a vein) infusion.

For treatment of osteoporosis, including the treatment and prevention of osteoporosis caused by steroid medications, the recommended dose is 5 mg given as an intravenous (into a vein) infusion once a year. Infusions are given by a doctor or nurse over at least 15 minutes.

It is recommended that people taking this medication take calcium and vitamin D supplements to prevent low blood calcium levels. Your doctor will recommend a dose of these supplements based on your needs.

On the day of the infusion, it is important to drink at least 500 mL (2 cups) of fluids before and after the treatment.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are receiving the medication without consulting your doctor.

It is important to receive this medication exactly as recommended by your doctor. If you miss an appointment to receive zoledronic acid, contact your doctor as soon as possible to reschedule your appointment.

This medication is stored at room temperature and should be kept out of the reach of children.

Each bottle of ready-to-use sterile solution for intravenous infusion contains 5.330 mg of zoledronic acid monohydrate (equivalent to 5 mg zoledronic acid) per 100 mL. Nonmedicinal ingredients: mannitol, sodium citrate, and water for injection. The colourless plastic bottle is sealed with a rubber stopper which is held in place with an aluminum cap with flip component. The stopper is made of bromobutyl rubber coated with fluorocarbon polymer and contains no latex.

Do not use zoledronic acid if you:

• are allergic to zoledronic acid or any ingredient of this medication
• are allergic to any other bisphosphonate medication (e.g., alendronate, etidronate)
• are pregnant or breast-feeding
• have severely decreased kidney function
• have low blood calcium levels that have not been corrected

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• back pain
• constipation
• cough
• decreased appetite
• diarrhea
• dizziness
• excessive sweating
• fatigue
• fever and chills
• flu-like symptoms (e.g., fever, chills, bone pain, or muscle and joint pain)
• general feeling of being unwell
• headache
• joint inflammation
• low blood pressure
• nasal congestion
• nausea
• rash
• skin reaction at the injection site (e.g., redness, swelling or pain)
• sore throat
• tiredness
• vaginal dryness
• vomiting
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• broken bones not healing
• decreased sensation of touch
• eye pain, redness, or inflammation
• fast or irregular heartbeat
• high cholesterol
• joint and bone pain, joint stiffness, muscle spasms
• pain in the extremities
• persistent ear pain
• sensitivity of the eyes to light
• signs of osteonecrosis of the jaw (e.g., swelling or gum infections, bad breath, poor healing of the gums, feeling of numbness or heaviness in the jaw)
• signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
• shortness of breath, wheezing, or coughing (if allergic to ASA)
• signs of kidney failure (e.g., weakness, tiredness, loss of appetite, puffy eyes, hand and feet, decreased urine production or changed urine colour)
• signs of low blood calcium levels (e.g., muscle spasms, tingling or numbness of the fingers and mouth, twitching, or memory loss)
• skin rash
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)
• thigh or groin pain
• weakness

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a severe allergic reaction (e.g., hives; difficulty breathing; swelling of the mouth, lips, tongue, or throat)
• signs of stroke (e.g., sudden or severe headache; sudden loss of coordination; vision changes; sudden slurring of speech; or unexplained weakness, numbness, or pain in the arm or leg)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

ASA allergy: Although not reported with zoledronic acid, people who are allergic to acetylsalicylic acid (ASA) have had breathing problems after using other medications in the same family as zoledronic acid. Let your doctor know if you are allergic to ASA.

Atrial fibrillation: This medication has been shown to increase the risk of atrial fibrillation (irregular heartbeat) in some clinical trials. Contact your doctor if you feel palpitations, a rapid and irregular heartbeat, dizziness, weakness, or shortness of breath.

Atypical femur fracture: There is evidence that long-term use of this class of medication may contribute to a type of rare fracture of the long bone in the thigh (femur) without any form of injury. If you experience new or unusual pain in the groin, hip, or thigh area, contact your doctor as soon as possible.

Deterioration of the jaw bone: People with cancer who are being treated with zoledronic acid (or other bisphosphonates) have a higher risk of developing osteonecrosis of the jaw (deterioration of the jaw bone). If you take zoledronic acid, report any pain, swelling, or infection of the jaw to your doctor, and avoid invasive dental procedures such as tooth extractions.

Eye inflammation: People using zoledronic acid have reported experiencing symptoms of eye inflammation. If you experience changes to your vision, red eyes, or eye pain, contact your doctor as soon as possible.

Hydration: If you are using this medication, you must be well-hydrated, especially if you are taking diuretics (water pills). On the day that zoledronic acid is given, you should eat normally and drink at least 2 glasses (500 mL or 2 cups) of water before and after receiving the medication.

Kidney function: As with other bisphosphonates, the use of zoledronic acid has been associated with kidney problems. If you have kidney disease, or have a history of kidney disease, let your doctor know about these conditions before starting this medication, as it may aggravate kidney problems. The use of zoledronic acid is not recommended for people with severe kidney impairment.

Low blood calcium levels: Before starting zoledronic acid, people who have low blood calcium levels must adjust their levels with calcium and vitamin D supplements as recommended by their doctors. If you take zoledronic acid, you should take calcium and vitamin D supplements to prevent low blood calcium levels. Your doctor will recommend an appropriate dose for these supplements based on your needs.

Pregnancy: Zoledronic acid should not be used during pregnancy as it may harm the developing baby. If you become pregnant while receiving this medication, contact your doctor immediately.

Breast-feeding: It is not known if zoledronic acid passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 18 years of age.

There may be an interaction between zoledronic acid and any of the following:

• aminoglycosides (e.g., gentamicin, tobramycin)
• calcitonin
• capecitabine
• diuretics (water pills; e.g., bumetanide, furosemide)
• non-steroidal anti-inflammatory medications (NSAIDs; e.g., celecoxib, diclofenac, ibuprofen, naproxen)
• phosphate supplements
• medications that prevent blood vessel growth in tumours (e.g., axitinib, bevacizumab, lenalidomide, pazopanib, regorafenib, sorafenib, sunitinib, thalidomide)
• proton pump inhibitors (e.g., lansoprazole, omeprazole)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.