Zoledronic acid

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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.

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.

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.

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: 

• medicines you have been prescribed
• medicines you buy in a shop, pharmacy or online
• vitamins or supplements 
• herbal drugs and complementary or homeopathic therapies
• recreational drugs – for example, cannabis.

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. 

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.

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.