Zoledronic acid (Zometa®)
Zoledronic acid is a bone-strengthening drug which can be used in myeloma (cancer of the plasma
cells), and when cancer has spread to the bones (secondary bone cancer). It can also be given
to people who are at high risk of osteoporosis after their cancer treatment.
This information is best read with our information on secondary bone cancer, myeloma or
breast cancer.
In this information:
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How zoledronic acid works
How zoledronic acid is given
Possible side effects of zoledronic acid
Less common side effects
Other information about zoledronic acid
References and thanks
How zoledronic acid works
Zoledronic acid belongs to a group of drugs called bisphosphonates. Bones affected by cancer
can become weaker which may increase the risk of a broken bone (fracture). Zoledronic acid
makes the bone stronger, reduces the risk of getting a fracture and reduces pain in the bones.
In healthy bone, cells called osteoclasts and osteoblasts work together to keep our bones strong.
Osteoclasts break down old bone while osteoblasts build new bone. When a bone is affected
by cancer, the osteoclasts become overactive and break down more bone, making it weaker.
Bisphosphonates stop osteoclasts from doing this.
Zoledronic acid is also given to reduce high levels of calcium in the blood (known as
hypercalcaemia). Hypercalcaemia is when the damaged bones lose calcium, which then leaks
into the blood. This causes symptoms such as feeling or being sick (nausea and vomiting),
tiredness (fatigue), irritability and, sometimes, confusion. Zoledronic acid gets rid of the extra
calcium from the blood.
You may also be given zoledronic acid if you have had prostate cancer or early breast cancer.
This is because some treatments, such as hormonal therapies, may increase your risk of bone
thinning (osteoporosis). Zoledronic acid can help prevent osteoporosis and reduce the risk of
fractures by strengthening the bones.
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How zoledronic acid is given
You have zoledronic acid as a drip (infusion) into the vein 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 and is given every 3-4 weeks.
If you are having zoledronic acid to reduce pain or strengthen your bones, you will usually take it
for as long as it is working.
Zoledronic acid to lower calcium levels is usually given as a single dose.
Possible side effects of zoledronic acid
We explain the most common side effects of zoledronic acid here. But we don’t include all the
rare ones that are unlikely to affect you. You may get some of the side effects we mention, but
you are very unlikely to get all of them. If you are having other drugs as well, you may have some
side effects that we don’t list here.
Always tell your doctor or nurse about the side effects you have. Your doctor can prescribe drugs
to help control some of these. It is very important to take the drugs exactly as your nurse or
pharmacist has explained. This means they will be more likely to work better for you.
Temporary increase in 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
Zoledronic acid may cause flu-like symptoms within the first three days of it being given. These are
usually mild and may include feeling hot or cold and/or shivery, having a headache, and aching.
Your doctor or nurse may advise you to take paracetamol. Drinking plenty of fluids will also help.
Feeling sick
Zoledronic acid can make you feel sick or be sick (nausea and vomiting). This is usually mild but
let your doctor or nurse know if this happens. They can prescribe anti-sickness drugs to control
sickness.
Headaches
Zoledronic acid may cause headaches. If this happens, let your doctor or nurse know. They can
give you non-prescription painkillers.
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Zoledronic acid (Zometa®)
Eye problems
Your eyes may become watery and feel sore. Your doctor can prescribe eye drops to help with this.
If your eyes get red and inflamed (conjunctivitis), tell your doctor. You may need antibiotic eye drops.
Very rarely, some people have changes to their vision such as blurriness. Always tell your doctor
if you have changes in your vision.
Anaemia (low number of red blood cells)
Zoledronic acid can reduce the number of red blood cells in your blood. These cells carry oxygen
around the body. If the number of red blood cells is low, you may be tired and breathless. Tell your
doctor or nurse if you feel like this.
Changes to the way your kidney works
Zoledronic acid can affect how your kidneys work. This is usually mild and goes back to normal
after treatment. You will have blood tests to check how well your kidneys are working. Your doctor
or nurse may ask you to drink plenty of fluid.
Less common side effects
Low level of calcium in the blood
Zoledronic acid can reduce the level of calcium in your blood to below normal. This is rare and
usually only temporary. It is unlikely to cause you any symptoms. Your doctor will check your levels
of calcium during your treatment by doing regular blood tests.
Jaw problems (osteonecrosis of the jaw)
A rare side effect of zoledronic acid is a condition called osteonecrosis of the jaw. This is when
healthy bone in the jaw becomes damaged and dies. Gum disease, problems with your dentures
and some dental treatments, such as having a tooth removed or having dental implants, can
increase the risk of this. Before you start taking the drug you’ll be advised to have a full dental
check-up. It’s very important to look after your teeth by brushing them regularly and having routine
dental check-ups. Always let your dentist know that you’re taking bisphosphonates.
Symptoms of osteonecrosis can include pain, swelling, redness of the gums, loose teeth or a
feeling of numbness or heaviness in your jaw. Tell your cancer specialist and dentist straight away
if you have any of these symptoms.
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Other information about zoledronic acid
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.
Zoledronic acid can interact with other drugs. This includes medicines you can buy in a shop or
chemist. Tell your doctor about any medicines you are taking, including ones you can buy for
yourself, complementary therapies and herbal drugs.
Medical or dental treatment
If you need to go into hospital for any reason other than cancer, always tell the doctors and nurses
that you are having zoledronic acid. Explain you are having treatment with bisphosphonates.
Tell them the name of your cancer doctor so they can ask for advice.
Always tell your dentist you are taking bisphosphonates.
Contraception
Your doctor will advise you not to become pregnant or to father a child during treatment. This is
because zoledronic acid may harm a developing baby. It’s important to use effective contraception
during and for a few months after treatment. You can talk to your doctor or nurse about this.
Breastfeeding
Women are advised not to breastfeed during treatment and for a few months after it finishes.
This is in case there is zoledronic acid in their breast milk.
References and thanks
The information in this section has been produced in accordance with the following sources
and guidelines:
• electronic Medicines Compendium (eMC). www.medicines.org.uk (accessed July 2014)
• Van Poznak C. Osteoclast inhibitors in the management of bone metastases from breast
cancer. www.uptodate.com/contents/osteoclast-inhibitors-in-the-management-of-bonemetastases-from-breast-cancer (accessed July 2014).
• Smith MR, Crawford ED. Side effects of androgen deprivation therapy. www.uptodate.com/
contents/side-effects-of-androgen-deprivation-therapy? (accessed July 2014)
• Lewiecki EM. Prevention of osteoporosis. www.uptodate.com/contents/prevention-ofosteoporosis (accessed July 2014)
If you’d like further information on the sources we use, please feel free to contact us.
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Thanks
Thanks to Hannah Fletcher, Specialist Pharmacist, who reviewed this edition.
Thank you to all of the people affected by cancer who reviewed what you’re reading and have
helped our information to grow.
You could help us too when you join our Cancer Voices Network - find out more.
Content last reviewed: 1st July 2014
Next planned review: 2016
We make every effort to ensure that the information we provide is accurate and up-to-date but it should not be relied
upon as a substitute for specialist professional advice tailored to your situation. So far as is permitted by law, Macmillan
does not accept liability in relation to the use of any information contained in this publication or third party information
or websites included or referred to in it.
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