What is clodronate?

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

Clodronate can be given with other cancer treatments.

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 two 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 clodronate works

Clodronate reduces the activity of osteoclasts. This can help 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 taken by mouth as capsules or tablets. You usually take it once or twice a day. 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.

Always take clodronate tablets exactly as you are told to. 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.

  • 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, do not eat, drink (other than tap water) or take any other medicines by mouth for 1 hour.

  • If you take clodronate twice a day

    Take the first dose as above. Take the second dose between meals, at least 2 hours after and 1 hour before eating, drinking (other than tap water) or taking any other medicines by mouth. Other things to remember about your capsules or tablets:

    • Keep them in the original package.
    • Keep them safe and out of sight and reach of children.
    • If your treatment is stopped, return any unused clodronate to the pharmacist. 

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, you may continue it for as long as it helps manage the symptoms.

About side effects

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

You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Serious and life-threatening side effects

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

Contact the hospital

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

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.

Common side effects

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.


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

If you have diarrhoea:

  • try to drink at least 2 litres (3½ pints) of fluids each day
  • avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods
  • contact the hospital for advice.

Less common side effects

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.

You may be asked 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 any supplements are needed.

Effect on the kidneys

This treatment can affect how your kidneys work. Drinking plenty of fluids will help your kidneys work well. You will have blood tests to check how well your kidneys are working. Tell your doctor if:

  • you feel generally unwell
  • have any swelling of your face, arms, legs or tummy
  • you notice a change in how often you pass urine (pee).

Effects on the liver

Clodronate can affect the liver. This is usually mild and does not cause any symptoms. It goes back to normal after treatment. You will have blood tests to check how well your liver is working.

Pain in the thigh, hip or groin

Rarely, people having 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 and mention that you are taking bisphosphonates. They can arrange tests to check the thigh bones for any signs of weakness or fracture.

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.

Allergic reaction

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

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 when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.


If you are pregnant, think you may be pregnant, or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.


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

Your doctor or nurse can give you more information.