Bisphosphonate therapy

Bisphosphonates are a group of drugs used in the management of secondary bone cancer. This information leaflet explains how they work, when they may be prescribed and what side effects may occur.

How do bisphosphonates work?

Healthy bones are constantly being broken down and renewed. This process is a delicate balance of the breaking down of old bone and the rebuilding of new bone. When cancer spreads to the bone, the process is disrupted and more bone is broken down than is replaced. This can cause pain and weakening of the bones, which means they may be more at risk of fracture. Bisphosphonates work by slowing down the process of bone breakdown.

When are bisphosphonates prescribed?

Bisphosphonates are used to help control bone pain and reduce the risk of possible problems, such as fractures. Bisphosphonates are also used to treat a condition called hypercalcaemia, which can be a complication of cancer. This is where too much calcium leaks from the bones into the bloodstream and causes symptoms such as thirst, nausea, fatigue, weakness, poor appetite and constipation, confusion and drowsiness. Once prescribed, they may be given indefinitely until your Specialist decides you will no longer benefit from them for bone pain but can also be a one-off treatment for raised blood calcium levels.

How are bisphosphonates given?

Bisphosphonates are most commonly given through a drip (intravenously). Some bisphosphonates can be given by mouth.

Commonly used bisphosphonates

A number of different bisphosphonates are used in the management of secondary bone cancer. You should discuss with your Specialist which is the best drug for you and the best way for it to be given.

• Disodium pamidronate (Aredia)

Disodium pamidronate is given intravenously over approximately 1½-2 hours, every 3-4 weeks.

• Zoledronic acid (Zometa)

Zoledronic acid is given intravenously over a period of at least 15 minutes, every 3-4 weeks.

• Ibandronic acid (Bondronat)

Ibandronic acid may be given intravenously and is used for patients who have poor kidney function. It is also available as a tablet that can be taken by mouth. When your doctor feels that long term treatment will be helpful, they may recommend Ibandronic acid to be taken daily by mouth rather than continuing with intravenous treatment.

What are the side effects of bisphosphonates?

Bisphosphonates can cause a variety of side effects. The more common side effects usually occur within the first 48 hours after treatment and get better on their own; these are headache, bone or muscle pain, or joint discomfort. You may experience flu-like symptoms such as fever, hot flushes and chills after the first treatment.

Less common side effects may include pain and/or redness or inflammation at the injection site. You may also experience generalised pain, tiredness, nausea and vomiting.

Rare side effects include muscle cramps, abdominal pain, agitation, dizziness, sleeplessness, drowsiness and exhaustion. Intravenous bisphosphonates can, in rare cases, cause kidney damage but not all bisphosphonates carry the same risk.

Rarely, bisphosphonate infusions can cause potentially serious bone problems in the jaw. For this reason you are advised to consider having a dental examination and complete any treatment, e.g. tooth extractions, before commencing bisphosphonates. If you need to see a dentist at any time, please inform them that you are receiving bisphosphonates and ask them to contact a doctor at the hospice if they need any information and advice regarding the implications of this.

Occasionally, patients receiving infusions of Zoledronic acid may experience a fall in the level of calcium in the blood. For this reason you should take a calcium supplement (called Adcal D3) for two weeks after each treatment.

You will need to have your blood checked for kidney function and calcium levels before each treatment.