What is zoledronic acid?

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

  • help protect the bones from the effects of some treatments for early breast cancer
  • reduce the risk of early breast cancer spreading to the bones – this is called adjuvant treatment
  • reduce a raised calcium level in the blood caused by cancer that has spread to the bones
  • treat bone weakness or pain caused by myeloma or by breast cancer that has spread to the bones.

Early breast cancer means the cancer has not spread beyond the breast or nearby lymph nodes. 

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 in the bone. This is called secondary cancer or metastasis.

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.

More information about this treatment

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

The effect of cancer on the bones

Bones are living and constantly renew themselves. This helps bones keep their strength and shape.

Inside the bones, there are 2 types of bone cell:

  • osteoclasts, which break down and remove old bone
  • osteoblasts, which build new bone.

When we are children and young adults our bones keep getting thicker and stronger. But, as we get older, osteoclasts begin to remove more bone than osteoblasts make. This means our bones slowly become thinner (less dense). In some people, too much bone is lost and they have an in-creased risk of bone fractures.

Myeloma and some secondary bone cancers make chemicals that cause osteoclasts to destroy more bone. 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 mye-loma may lose calcium from the bones 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
  • confusion.

How zoledronic acid works

Zoledronic acid reduces the activity of the osteoclasts. This can help reduce pain and strengthen the bone. For breast cancer, it can reduce the risk of cancer spreading to the bones.

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

How zoledronic acid is given

Zoledronic acid can be given on its own or with other cancer treatments.

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

Your course of zoledronic acid

How long zoledronic acid is given for depends on why you are having the treatment.

  • If you are having zoledronic acid to help prevent the cancer coming back, you will have an infusion once every 6 months for 3 to 5 years.
  • If you are having zoledronic acid to reduce pain or strengthen your bones, you usually have an infusion every 3 to 4 weeks. You may also need to take calcium and vitamin D supplements. You usually need to take zoledronic acid for at least 2-3 months before it has the maximum effect on your bones. After that, you can usually take it for as long as it is working well 
  • If you are having zoledronic acid to lower calcium levels in your blood, it is usually given as a single dose. 

Your doctor will tell you more about your treatment and how long you may need to have it.

Dental check-up before treatment

Rarely, this treatment can affect the jawbone. You can read more about this in the “Less common side effects” section below.

Having a healthy mouth and teeth reduces your risk of jaw problems. You usually need a dental check-up to check for any problems before you start treatment.

If you need urgent treatment to lower high calcium levels in your blood, you do not usually need a dental check-up first.

About side effects

About side effects

We explain the most common side effects of this treatment here. We also include some that are less common. 

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

Always tell your doctor, nurse or pharmacist about any side effects you have. They can give you: 

  • drugs to help control some side effects 
  • advice about managing side effects. 

It is important to take any drugs exactly as explained. This means they will be more likely to work for you.

Serious and life-threatening side effects

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

Contact the hospital

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

Possible side effects

Flu-like symptoms

Some people have flu-like symptoms, such as:

  • a high temperature
  • chills
  • pains in your muscles or joints.

Tell your doctor if these effects do not get better within 2 days or are causing problems. It may be helpful to take mild painkillers such as paracetamol. Your doctor, nurse or pharmacist can give you advice.

Pain in the thigh, hip or groin

Sometimes pain in muscles or bones gets worse for a short time when you start taking zoledronic acid. If this happens, your doctor can prescribe painkillers for you until it gets better.

Rarely, people on this treatment develop a break (fracture) in their thigh bone without any obvious cause. Sometimes both thigh bones are affected.

If you have any thigh, hip or groin pain, tell your doctor. Mention that you are taking bisphosphonates. They can arrange tests to check the thigh bones for any signs of weakness or fracture.

Anaemia (low number of red blood cells)

This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may feel:

  • very low in energy
  • breathless 
  • dizzy and light-headed. 

If you have these symptoms, contact the hospital straight away on the 24-hour number. You may need treatment for anaemia. If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Feeling tired (fatigue)

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest between activities.

Being physically active can help to manage tiredness and give you more energy. It also:

  • helps you sleep better
  • reduces stress
  • improves your bone health.

If you feel sleepy, do not drive or operate machinery.

Headaches

This treatment may cause headaches. If you have headaches, tell your doctor, nurse or pharmacist. They can give you advice about painkillers that may help. Tell them if the headache does not get better, or gets worse.

Red or sore eyes

This treatment can affect your eyes and eyesight. Tell your doctor if you have red or sore eyes. They can prescribe eye drops to help.

Feeling sick

You may feel sick or be sick (vomit) during treatment. This is usually mild. Your doctor can prescribe anti-sickness tablets to help.

Take the drugs exactly as your nurse or pharmacist tells you to. It is easier to prevent sickness than treat it after it has started.

Diarrhoea

This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. You may also have stomach cramps. If you have a stoma, it may be more active than usual. 

If you are passing loose stools 3 or more times a day and this is not normal for you, contact the hospital as soon as possible on the 24-hour number. Follow the advice they give you about:

  • taking anti-diarrhoea medicines 
  • drinking enough fluids to keep you hydrated and to replace lost salts and minerals
  • any changes to your diet that might help. 

They might also ask you for a specimen of your stool to check for infection.

Effects on the heart

This treatment can affect the way the heart works. You may have tests to see how well your heart is working. These may be done before, during, and sometimes after treatment.

Contact a doctor straight away if you:

  • have pain or tightness in your chest
  • feel breathless or dizzy
  • feel your heart is beating too fast or too slowly.
  • notice any changes to your heart rhythm.

Other conditions can cause these symptoms, but it is important to get them checked by a doctor straight away.

Effects on the kidneys

This treatment can affect how the kidneys work. This is usually mild and goes back to normal after treatment ends. You will have blood tests to check how well your kidneys are working. Contact the hospital on the 24-hour number if you:

  • have blood in your urine (pee) 
  • are passing less urine or peeing less often than usual.

Drinking fluids helps protect your kidneys. The advice is usually to try to drink at least 2 litres (3½ pints) of fluid each day. But follow any advice from your doctor, nurse or pharmacist about how much is right for you.

Numbness or tingling

You may notice numbness or tingling around the mouth, or in the fingers and toes. This may be caused by low levels of calcium in your blood. You will have regular blood tests to check your calcium levels. Contact your doctor straight away if you have these symptoms.

Your doctor may ask you to take calcium and vitamin D supplements, unless you are having this treatment to lower the levels of calcium in your blood. Your doctor will let you know if you need any supplements.

Less common side effects

Allergic reaction

This treatment might cause an allergic reaction. But this is not common. Signs of a reaction can include: 

  • a skin rash or itching
  • feeling breathless or wheezy
  • swelling of your face, mouth or throat.

If you feel unwell or have any of these signs, contact the hospital straight away on the 24-hour number. Do not take any more of this treatment until you have checked with them.

Jaw problems

Rarely, this treatment can affect the jawbone. Healthy bone in the jaw becomes damaged and dies. This is called osteonecrosis of the jaw (ONJ). It can cause:

  • pain
  • loosening of the teeth
  • problems with the way the gums heal.

The risk of jaw problems is higher after some types of dental treatment and in people who have gum disease or dentures that do not fit well.

It is important to avoid having any dental treatment that could affect your jawbone when you are having bisphosphonates. This includes having a tooth or root removed or dental implants put in. You can still have fillings, gum treatments or a scale and polish.

To reduce your risk of developing jaw problems 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 a bisphosphonate before having any dental treatment.

Tell your cancer specialist and dentist straight away if you at any time you develop:

  • pain
  • swelling or redness in your gums
  • numbness or heaviness in your jaw
  • loose teeth.

Ear problems

Very rarely, bones in the outer ear may be affected by this treatment. Always tell your doctor if you have any:

  • ear pain
  • discharge from your ear
  • ear infections.

You should also let them know if you notice any other changes in your ears or hearing.

Other information

Going into hospital

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

Other medicines

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

Contraception

Your doctor, nurse or pharmacist will advise you not to get pregnant or make someone pregnant while having this treatment and for some time afterwards. The drugs may harm a developing baby. It is important to use contraception to prevent pregnancy. Follow their advice about:

  • what types of contraception to use 
  • how long after treatment you should continue to use contraception. 

Breastfeeding

You are advised not to breastfeed while having this treatment, or for some time after treatment ends. This is because the drugs could be passed to the baby through breast milk. 

Your doctor, nurse or pharmacist can give you more information.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 September 2022
|
Next review: 01 April 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.