Clodronate is a type of drug called a bisphosphonate. It can be used to treat bone weakness or pain caused by myeloma or breast cancer that has spread to the bone (secondary bone cancer). Clodronate can also be used to treat high levels of calcium in the blood.

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.

Clodronate 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.

You take clodronate by mouth. It is very important to take it as directed. Clodronate 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.

Clodronate (Bonefos®, Clasteon®, Loron®)

Clodronate 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.

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.

Clodronate 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 clodronate works

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

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

How clodronate is given

Clodronate is usually taken by mouth as capsules or tablets, once or twice a day.

Always take clodronate tablets exactly as explained. This is important to make sure they work as well as possible for you. Check with your doctor or pharmacist if you are not sure.

Clodronate should be swallowed whole with tap water. Never take it with milk because this reduces the amount of clodronate your body can absorb.

You need to drink plenty of fluids, such as water, while you are taking clodronate treatment.

If you take clodronate once a day

Take your tablets in the morning on an empty stomach with a glass of tap water. After taking clodronate, don’t eat, drink (other than tap water) or take any other medicines by mouth for one hour.

If you take clodronate twice a day

Take the first dose as recommended above. Take the second dose between meals, at least two hours after and one hour before eating, drinking (other than tap water) or taking any other medicines by mouth.

It is important to follow these instructions or your body will not absorb the drug properly.

How long clodronate is given for

If you are having clodronate to lower your calcium level, you may be given tablets or capsules to maintain your calcium at a normal level. If your calcium level is very high, you may be given a single dose of another bisphosphonate into a vein to bring it down faster.

If you are having clodronate to reduce pain or strengthen your bones, then you may need to take it for as long as it seems to be working.

Possible side effects of clodronate

Some people have very few side effects while others may have more. The side effects described here won't affect everyone having clodronate. 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.

Feeling sick (nausea) or being sick (vomiting)

This is usually mild. It can be controlled with anti-sickness (anti-emetic) tablets.

Abdominal (tummy) pain and diarrhoea

Sometimes, clodronate can cause diarrhoea. This can usually be controlled with anti-diarrhoea tablets. Let your doctor know if it is severe or continues. If you have diarrhoea, drink at least 2 litres (3½ pints) of fluid a day.

Less common side effects

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.

Effect on the kidneys

Clodronate can affect how your kidneys work. It is important to drink plenty of fluids while taking clodronate. 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.

Jaw problems

Rarely clodronate 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 clodronate 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.

Allergic reaction

Rarely clodronate can cause an allergic reaction. If you suddenly feel breathless or develop an itchy rash seek medical advice immediately.

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 find out who you should contact if you have any problems or troublesome side effects when you’re at home.

Other medicines

Some medicines can increase the side effects of clodronate or make it work less well. This includes medicines and supplements you can buy in a shop or chemist. Tell your doctor about any medicines you are taking, including over-the-counter drugs, complementary therapies and herbal drugs.

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 breast feed if taking clodronate.

Back to Bisphosphonates

Ibandronic acid

Ibandronic acid can strengthen bones and treat high calcium levels in the blood.

Pamidronate (Aredia®)

Pamidronate can lower calcium levels in the blood and strengthen bones and relieve pain in people with some secondary bone cancers.

Zoledronic acid

Zoledronic acid can protect and strengthen bones in people with myeloma or some types of cancer that have spread to the bone.