What are bisphosphonates?
Bisphosphonates are a group of drugs used to manage and prevent complications from cancer in the bone. 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 usually 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. They are given regularly and may be given indefinitely or until your Specialist assesses that you will no longer benefit from them.
Bisphosphonates are also used to treat a condition called hypercalcaemia (high calcium levels), 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 excessive thirst, nausea, fatigue, weakness, poor appetite and constipation, confusion and drowsiness.
How are bisphosphonates given?
Bisphosphonates are most commonly given through a drip (intravenously), although in some cases they can be given by mouth. At the hospice we offer an outpatient clinic which you can attend regularly for your treatment.
What are the commonly used bisphosphonates?
A number of different bisphosphonates are used in the management of secondary bone cancer. The two most commonly used by the hospice are pamidronate and zoledronic acid.
Disodium pamidronate is given intravenously over approximately 1½-2 hours, every 3-4 weeks.
Zoledronic acid is given intravenously over a period of at least 15 minutes, every 3-4 weeks.
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 headaches, 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. Most patients find these side effects are manageable and time limited. Rare side effects include muscle cramps, abdominal pain, agitation, dizziness, sleeplessness, drowsiness and exhaustion.
Intravenous bisphosphonates can, in rare cases, cause kidney damage and decrease the level of calcium in the blood. You will need to have regular blood tests to monitor this. Once the bisphosphonate has been discontinued these problems may reverse.
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.
If you are concerned about anything in relation to your bisphosphonate treatment, please contact any of the doctors or nurses at the hospice.