Bonefos (sodium clodronate)

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Your doctor has recommended a course of tablets called Bonefos which is used to protect the bones from the effects of cancer which may have spread to them.

How do cancer cells effect the bones? It is possible in some patients for cancer cells to spread from its original site, for example the breast, to the bones. They then grow into small tumours which release chemicals which upset the normal balance between bone formation (osteoblast cells)  and bone re-absorption (osteoclast cells).

These chemicals stimulate osteoclasts to excessively reabsorb bone, release calcium into the blood stream, reduce bone density, leading to holes in the bones and weakness. Weak bones lead to bone pain and fracture. A high calcium blood level (Hypercalcaemia) can cause a number of troublesome symptoms including; dry mouth, thirst & dehydration due to passing of excessive urine, constipation, nausea & vomiting, severe tiredness, muscle weakness and low mood leading to depression.

How does Bonefos work?   Bonefos contains sodium clodronate - a member of a group of drugs called bisphosphonates. Bonefos blocks the function of the cells which reabsorb bone (osteoclasts) but does not effect the cells which strengthen bone (osteoblasts). Clinical trials have shown that inhibiting bone re-absorption corrects and prevents the release of too much calcium into the blood stream, reduces bone pain, reduces the occurrence of fractures and maintains or improves general well being.

Who takes Bonefos?   Mainly patients who have a cancer which has spread to the bones. Most often these are patients with breast cancer but it is sometimes recommended for patients with other types of cancer including prostate, lung and myeloma. It is most often given to patients where the cancer in the bone has caused pain or signs of bone weakness.  It is particularly recommended if the level of calcium in the blood stream is raised either after it has been controlled with an intravenous infusion or on its own.

New studies are underway and some have already suggested that sodium clodronate may also be of use in women who are at risk of developing disease in the bone but do not have any evidence of it on any scans at the present time (see having a bone scan). Some of these studies have suggested that sodium clodronate has prevented the spread of cancer to the bones.

How should Bonefos be taken?  Two Bonefos tablets taken per day (each containing 800 mg of Sodium Clodronate).  They can be taken at the same once a day or one tablet taken twice per day. They should be taken at least 1 hour before or 1 hour after a meal. The tablets should be swallowed with a drink not containing milk as calcium reduces the absorption of sodium clodronate. It is also important to avoid iron, mineral supplements or ant-acids for indigestion and to maintain adequate fluid intake. Occasionally patients are asked to take four tablets a day.

Where do you obtain more tablets? Bonefos is generally first prescribed by a specialist at the hospital, most often an oncologist. Although you will still have regular supervision at the hospital, including blood tests, in the long run you will be asked to obtain a repeat prescription from  your general practitioner (GP). This is called shared care. The GP will let the specialist know if there are any unforeseen events on this drug and the specialist will keep the GP up to date with the response to the drug and how long the patient should take it for.

Side effects

Bonefos is generally well tolerated but occasionally side effects can occur. Mild symptoms are usually in the form of tummy upset:-

Mild nausea Mild indigestion Mild diarrhoea

If these develop it is recommended that the dose is reduced by half for a few days and then gradually increased back to two tablets a day but taken separately. A slight change in the diet may also be required. For more information about specific diet alterations go to our advice sheets on diet and diarrhoea and/or diet and indigestion. If someone has a history of inflammatory bowel disease they should not take Bonefos unless under strict supervision.

Patients who have moderate to severe renal failure should only take Bonefos only under strict supervision. Care should be taken with Bonefos if it is taken with non-steroidal anti-inflammatory drugs.

Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.

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