Zoledronic acid

Zoledronic acid is a type of drug called a bisphosphonate.

It can be used to

  • Treat bone weakness or pain caused by myeloma or cancer that has spread to the bone 
  • Treat high levels of calcium in the blood
  • Prevent breast cancer spreading to the bones.

Myeloma or secondary bone cancer may cause the bones to lose calcium, making them weak and painful. The calcium goes into the blood. If blood levels of calcium are too high it can cause sickness, tiredness, irritability and confusion.

Zoledronic acid reduces the amount of calcium lost from the bones. This can help strengthen the bones and reduce pain. It can also help to bring blood levels of calcium back to normal.

Zoledronic acid is given as a drip (infusion) into the vein. Zoledronic acid can cause side effects. If these happen they are usually mild but occasionally can be severe. It is important to read the detailed information below so that you are aware of possible side effects. Tell your doctor or nurse if you notice any changes.

Zoledronic acid (Zometa®)

Zoledronic acid belongs to a group of drugs called bisphosphonates. It can be used to treat:

  • a raised calcium level in the blood caused by cancer that has spread to the bones 
  • bone weakness or pain caused by myeloma or by breast cancer that has spread to the bones. 
  • to help prevent cancer spreading to the bones in women who have been treated for breast cancer and are post-menopausal.

Cancer that has spread to the bones is called secondary bone cancer. It happens when cells from the original (primary) cancer spread to form a new tumour (secondary cancer or metastasis) in the bone.

Myeloma is a cancer of a type of blood cell called plasma cells. The abnormal plasma cells build up inside bones causing pain and weakness.

Zoledronic acid can be given alongside other cancer treatments.

The effect of cancer on the bones

In normal bone, two types of cell called osteoclasts and osteoblasts work together to keep your bones healthy:

  • Osteoclasts destroy old bone.
  • Osteoblasts build new bone.

Myeloma and some secondary bone cancers make chemicals that cause osteoclasts to work harder. This means that more bone is destroyed than rebuilt. The affected bone becomes weak and painful and can break more easily.

Bones contain calcium, which gives them strength. A bone affected by secondary cancer or myeloma may lose calcium into the blood. A raised level of calcium in the blood is called hypercalcaemia. This may cause you to have symptoms including feeling sick (nausea), vomiting, tiredness, irritability and sometimes confusion.

How zoledronic acid works

Zoledronic acid reduces the activity of the osteoclasts. This can help to reduce pain and strengthen the bone.

Zoledronic acid also reduces the amount of calcium lost from the bones. This helps calcium levels in the blood return to normal.

How zoledronic acid is given

Zoledronic acid is given by a drip (infusion) into the vein through a fine tube called a cannula. It is usually given in the outpatient department at the hospital. The infusion takes at least 15 minutes and is usually given every 3-4 weeks.

If you are having zoledronic acid to help prevent the cancer coming back, you will have an infusion every 6 months for up to three years.

How long zoledronic acid is given for

If you are having zoledronic acid to reduce pain or strengthen your bones, you may need to have it for as long as it seems to be working.

Zoledronic acid to lower calcium levels is usually given as a single dose.

Possible side effects of zoledronic acid

Some people have very few side effects while others may have more. The side effects described here won't affect everyone having zoledronic acid. If you are taking other drugs, you may have some side effects that we don’t list here.

We explain the most common side effects here but haven't included those that are rare and therefore unlikely to affect you. If you notice any effects that aren't listed below, discuss them with your doctor or nurse.

Increased pain

Sometimes pain in the affected bone can become worse for a short time when you start taking zoledronic acid. If this happens, your doctor can prescribe painkillers for you until it wears off.

Flu-like symptoms

These include a high temperature, chills, and pain in your muscles or joints. Let your doctor know if these effects are troublesome. It may be helpful to take mild painkillers.

Less common side effects of zoledronic acid

Numbness or tingling around the mouth or in the fingers and toes

You may notice this if the calcium level in your blood drops below normal. Your doctor will do regular blood tests to monitor your calcium levels. Contact a doctor straight away if you have any of these symptoms.

You may be asked to take calcium and vitamin D supplements while having treatment with zoledronic acid. Your doctor will let you know if this is necessary.

Effect on the kidneys

Zoledronic acid can affect how your kidneys work. Drinking plenty of fluids will help your kidneys work well. Your doctor will check how well your kidneys are working with regular blood tests. Tell your doctor if you feel generally unwell, have any swelling of your face, arms, legs or tummy or you notice a change in how often you pass urine.

Red or sore eyes

Your doctor can prescribe eye drops to ease this.

Anaemia (low number of red blood cells)

Symptoms of anaemia include feeling very tired and breathless. Your doctor can check whether you're anaemic by doing a blood test.


This is not common, but it is important to let your doctor know if you are getting headaches. They will advise you about what medicines to take. It is also important to drink plenty of fluids.

Feeling sick (nausea) and being sick (vomiting)

If this happens, your doctor can prescribe anti-sickness (anti-emetic) drugs to help.

Jaw problems (osteonecrosis)

Rarely zoledronic acid can cause tissue in the jaw bone to die. This is called osteonecrosis of the jaw. The risk of this happening is higher in people who have gum disease, problems with dentures, or after a dental treatment such as having a tooth removed.

To reduce your risk your doctor will advise you to:

  • have a full dental check-up before starting treatment
  • look after your teeth and gums during treatment (ask your dentist for advice)
  • tell your dentist you are taking zoledronic acid before having any dental treatment.

You should always tell your cancer specialist and dentist straight away if you have pain, swelling or redness in your gums, numbness or heaviness in your jaw or loose teeth.

Additional information

Admission to hospital

If you are admitted to hospital for a reason not related to the cancer, it is important to tell the doctors and nurses looking after you that you are having treatment with bisphosphonates. You should tell them the name of your cancer specialist so that they can ask for advice.

Emergency contacts

It’s a good idea to know who you should contact if you have any problems or troublesome side effects when you’re at home.

Pregnancy and breastfeeding

Ask your doctor or pharmacist for advice before taking this medicine if you are pregnant, think you may be pregnant or are planning to have a baby. Women are advised not to breastfeed if taking zoledronic acid.

Back to Bisphosphonates


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