Sodium clodronate (Bonefos, Clasteon)

Sodium clodronate is a type of bisphosphonate drug. Doctors use it to treat cancers that affect the bones. The cancers most commonly treated are myeloma and secondary breast cancer. You may also have it to reduce high levels of calcium in the blood (hypercalcaemia) caused by any cancer that has spread to the bone.

You may have sodium clodronate as tablets or capsules. The tablets are called Bonefos and the capsules are called Clasteon or Bonefos. You take them with plenty of water – never milk. You need to take them on an empty stomach, so at least an hour before or after you have a meal, drink (except water) or other medicines. 

It is very important that you take tablets according to the instructions your doctor or pharmacist gives you. For example, whether you have a full or empty stomach can affect how much of a drug gets into your bloodstream. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first.

You may have sodium clodronate for the following reasons 

• To lower high blood calcium levels (hypercalcaemia)
• To strengthen weak areas of bone (osteolytic lesions)
• To reduce bone pain due to cancers that have spread to the bone

You may also have it to maintain calcium levels after a one off drip of a bisphosphonate drug.

We have listed the possible side effects of sodium clodronate below. There is general information about bisphosphonates in the cancer treatment section. You can find information about coping with side effects in our cancer drug side effects section.

More than 10 in every 100 people have one or more of these.

• Feeling or being sick is usually due to the tablets or capsules irritating your stomach – dividing the dose and taking half in the morning and half in the evening may help to reduce sickness
• Diarrhoea
• Clodronate can harm a developing baby so you should not become pregnant or father a child while taking this drug – discuss contraception with your doctor or nurse before you start your treatment if you think you or your partner could become pregnant
• It is not advisable to breastfeed while taking sodium clodronate because the drug may come through in the breast milk

Between 1 and 10 in every 100 people have one or more of these.

• A rash, which may be itchy
• Low levels of calcium in your blood (hypocalcaemia) – you will have blood tests to check the levels of calcium and other minerals such as potassium, phosphate and magnesium. A low calcium level can cause changes in sensation so you may have tingling or burning in your lips and tongue

Fewer than 1 in 100 people have these.

• Kidney changes – you will have regular blood tests to check how well your kidneys are working
• Breathlessness and a cough
• Osteonecrosis of the jaw can be a side effect of taking bisphosphonates for longer than a year – have a dental check up before you start treatment and tell your dentist that you are taking clodronate. Ask your doctor or specialist nurse to advise you about how to keep your mouth clean
• Red or peeling skin
• Fractures at the top of the thigh bone (femur) – let your doctor or nurse know if you have any pain in the top of the leg, your groin, or your hip
• Changes in lung tissue may lead to a cough, breathlessness or difficulty breathing – tell your doctor or nurse if you have any of these effects
• Severe bone, joint or muscle pain may occur some months after starting to take sodium clodronate

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

• How many times you've had the drug before
• Your general health
• The amount of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. Your nurse will give you a contact number. You can ring if you have any questions or problems. They can give you advice or reassure you. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies – some drugs can react together.