This information is about a drug called ibandronic acid that can be used when breast cancer has spread to the bones. If you have any more questions you can ask your doctor or nurse or speak to one of our cancer information nurse specialists.

Ibandronic acid belongs to a group of drugs called bisphosphonates. Bisphosphonates are commonly used to treat bone thinning (osteoporosis). In certain situations, bisphosphonates can help protect your bones against some of the effects of secondary bone cancer, such as pain and weakness. Secondary bone cancer occurs when the original cancer (the primary) spreads to form a secondary cancer (metastasis) in the bone.

Ibandronic acid can be given alongside other cancer treatments. At present, it may be given to women with breast cancer which has spread to the bones. It can be used to prevent and treat problems caused by secondary bone cancer and to reduce a raised calcium level in the blood.

As a result of secondary bone cancer, calcium (which helps strengthen the bones) can be lost from the damaged bone and can seep into the bloodstream. When the level of calcium in the blood becomes raised, this is known as hypercalcaemia. Hypercalcaemia can cause symptoms like feeling or being sick (nausea or vomiting), tiredness, irritability and sometimes confusion. Ibandronic acid helps to reduce high levels of calcium.

Secondary cancer in the bones may make them weak, and in some situations they may break (fracture). Ibandronic acid helps to strengthen the bone and reduce the risk of fractures. It also helps to reduce pain in the bones.

Cancer can affect the bones in different ways, and ibandronic acid is not helpful for all cancers that affect the bones. Your doctor or specialist nurse can tell you if ibandronic acid would be helpful for you.

In normal bone, two types of cell (osteoclasts and osteoblasts) work together to shape, rebuild and strengthen existing bone:

• osteoclasts destroy old bone
• osteoblasts build new bone.

Some secondary bone cancers produce chemicals that make the osteoclasts work harder. This means that more bone is destroyed than rebuilt, and leads to weakening of the affected bone. This can cause pain and means that the bone can fracture or break more easily.

Ibandronic acid targets areas of bone where there is cancer and the osteoclast activity is high. It helps to bring the balance of osteoclast and osteoblast activity back to normal. This can reduce pain and help to strengthen the bone. It also means that less calcium will be lost from the bones.

You may be given ibandronic acid by drip (infusion) or as a tablet.

If you are given it as an infusion, it will usually be done in the outpatient department at the hospital. Ibandronic acid is given by a drip into the vein through a fine tube called a cannula. The infusion can take up to an hour and is usually given every three to four weeks.

You may be given a single 'one-off' dose of ibandronic acid (as a drip) to lower a high calcium level.

Taking tablets

Usually you will take a tablet once a day. It’s important to carefully follow the advice on how to take your tablets. Your doctor, nurse or pharmacist will explain this to you.

It’s best to take the tablet first thing in the morning. Make sure that you take it on an empty stomach (do not eat or drink anything, or take any other medicines, for at least six hours beforehand). This is because ibandronic acid can attach itself to certain substances in food, drinks and medicines. If this happens it may not be absorbed properly and its effectiveness may be reduced as a result.

Swallow the tablet whole, with a full glass of plain tap water (not bottled mineral water). You’ll need to sit straight or stand up when you swallow it. This is to make sure the tablet is washed down well, to prevent it from irritating your gullet (tube from your mouth to your stomach).

Stay sitting or standing for an hour after you’ve taken the tablet. If you’re in bed, prop yourself up with pillows. Don’t drink (except plain tap water) eat, or take any medicines for up to an hour after you’ve swallowed the tablet.

Ibandronic acid usually needs to be taken for at least six months before it has its maximum effect. After that it can usually be taken for as long as it is working well for you.

Each person’s reaction to any medication is different. Most people have very few side effects, while others may experience more. The side effects described here will not affect everyone who is having ibandronic acid and may be different if you are having more than one drug.

We have outlined the most common side effects. However, if you notice any effects that are not listed here, please discuss them with your doctor or nurse.

Problems with swallowing or heartburn This may be a sign that the drug is irritating your gullet. If you find swallowing painful or difficult, or if you have heartburn (which is new or getting worse), stop taking ibandronic acid tablets. Let your doctor know as soon as you can.

Flu-like symptoms including a high temperature, chills, and pains in your muscles or joints can sometimes occur. Let your doctor know if these effects are troublesome. It may be helpful to take mild painkillers.

Indigestion and heartburn Let your doctor know if this is a problem and if it continues or gets worse. Your doctor can prescribe medicine to help with this.

If you’ve had stomach problems before, ibandronic acid can make them worse. Your doctor will monitor you closely if you’ve had problems with your stomach in the past.

Feeling sick (nausea) or being sick (vomiting) This is usually mild and can be controlled with anti-sickness tablets.

Abdominal (tummy) pain If you experience this, let your doctor know if it is severe or if it continues.

Drop in calcium levels below normal (tingling sensation in lips or tongue) This is usually only temporary. Your doctor will carry out regular blood tests to monitor the level of calcium in your blood.

Changes to how your bowel works (diarrhoea or constipation) Your doctor can prescribe medicine to help with this. Remember to drink plenty of fluids.

Headaches Some people have headaches with ibandronic acid. Let your doctor know if you are getting headaches.

Increased pain Sometimes pain in the affected bone can become worse for a short time when you start taking ibandronic acid. If this happens, your doctor can prescribe pain-relieving drugs for you until it wears off.

Itchy skin Ibandronic acid may make your skin feel itchy.

Feeling tired You may feel more tired than usual. Tell your doctor if this is a problem.

Taste changes You may notice that food tastes different and that you have a dry mouth.

Changes in your blood Ibandronic acid may cause changes in the blood, like anaemia (a low level of red blood cells). Your doctor can do blood tests to check this.

Change in kidney function Sometimes ibandronic acid can affect how the kidneys work. This does not usually cause any symptoms and the effects are generally mild. Your doctor will check how well your kidneys are working during your treatment by doing regular blood tests.

Jaw problems (osteonecrosis) This is a very rare side effect of ibandronic acid. It is more common in people who have had teeth removed or other dental procedures while taking ibandronic acid. Osteonecrosis is when healthy bone dies off in a way that is not normal. It can result in poor healing of the gums or loosening of teeth. If possible, dental treatment should be avoided while taking ibandronic acid. It’s important to let your dentist know that you are taking Ibandronic acid. Also, let your doctor know if you need dental treatment while taking ibandronic acid.

Ibandronic acid may harm an unborn baby. You should avoid becoming pregnant or breast feeding while taking this drug. If you are thinking of getting pregnant it’s best to talk to your specialist first.

You may be asked to take calcium and vitamin D supplements while having treatment with ibandronic acid. Your doctor will let you know if this is necessary.

This section has been compiled using information from a number of reliable sources, including:

• Aston V. Managing Bone Metastases through Bisphosphonate Treatment. Cancer Nursing Practice. 2005. Vol 4: Number 2.
• British National Formulary (57th edition). British Medical Association and Royal Pharmaceutical Society of Great Britain. September 2008.
• Coleman R E. The Role of Bisphosphonates in Breast Cancer. Breast. 2004. 13:S19-S28.
• Migliorati CA et al. Bisphosphonate-Associated Osteonecrosis: a Long-Term Complication of Bisphosphonate Treatment. Lancet Oncology. 2006. Vol 7:508-514.
• Regional Drug and Therapeutics Centre. The Use of Ibandronic Acid in the Management of Hypercalcaemia of Malignancy, Bone Pain and the Prevention of Skeletal Events Associated with Skeletal Metastases. www.nyrdtc.nhs.uk/docs/eva/ibandronic_acid.pdf (2007)

For further references, please see general bibliography.