What are bisphosphonates and what are they used for?
Bisphosphonates are a group of drugs that work by slowing bone loss. They reduce the risk of hip and spine fractures. Bone renewal is a slow process, but in many people an increase in bone density can be measured over five years of treatment.
Bisphosphonates can be taken by mouth (orally), through a drip (intravenous infusion) or by injection.
It's important to continue treatment as your doctor advises – even though you won't be able to feel whether it's working.
Because longer-term treatment can sometimes have side-effects your doctor may suggest a break from treatment after 3–5 years. The benefits of treatment last a long time though, so there's no need to worry that these will be lost if your doctor does suggest a 'treatment holiday'.
How are they taken?
There are several different bisphosphonates, and how they can be taken varies. The three ways in which they can be taken (administered) are:
- by mouth (orally)
- through a drip into a vein (intravenous infusion)
- by an injection into a vein (intravenous injection).
Oral bisphosphonates tend to be poorly absorbed by the body and can cause irritation of the gullet (heartburn), so it's very important that you carefully follow the instructions for taking your medication:
- Take it on an empty stomach with a glass or two of plain tap water. Other drinks may prevent the drug being properly absorbed by the body.
- You shouldn't eat anything or drink anything other than tap water, or take any other medication or supplements for at least 30 minutes afterwards (45 minutes for Bonviva). This is to help ensure the medication is effectively absorbed.
- You'll need to stay upright (sitting, standing or walking) for up to an hour afterwards to prevent the medication flowing back from your stomach and causing heartburn.
- You shouldn't lie down after taking bisphosphonates until after you've eaten.
If you can't tolerate bisphosphonates by mouth it's possible to have them through a drip into a vein (intravenous infusion) or as an injection:
- Pamidronate is given as an infusion – this takes about an hour and can be repeated every three months.
- Zoledronate is also given as an infusion – this takes 20 minutes or more but is only given once a year.
- Ibandronate can be given by mouth (monthly) or by intravenous injection (every three months). The injection takes seconds.
Side-effects and risks
Bisphosphonates are generally well tolerated. The risk of digestive problems with oral preparations is very much reduced if you carefully follow the instructions that come with your medicine.
Less common side-effects include:
- itchy rashes or photosensitivity (rash on exposure to sunlight)
- a sore mouth
- flu-like symptoms (more common with intravenous treatment)
- bone pain (more common with intravenous treatments)
- muscle pain
You should report any side-effects to your doctor or rheumatology nurse and the drug may be stopped if necessary.
There are three very rare side-effects:
- Osteonecrosis of the jaw is a condition where healing is incomplete following an invasive dental procedure. An area of bone is exposed through the gum and a small amount of bone dies. This condition is more common if you have cancer, are having chemotherapy or you have severe, recurrent dental infections and are having dental treatment.
- It's been suggested that there's a possible, though small, increase in the risk of cancer of the oesophagus (gullet) in people taking bisphosphonates by mouth for more than 3–5 years. However, the evidence is mixed and in most situations, the benefits of treatment are greater than any potential risk.
- Some people taking bisphosphonates have developed painful, partial or complete fractures in the upper, outer region of the thigh bone (femur) below the hip. Partial fractures are usually confirmed by a special diagnostic scan. The risk appears to increase the longer you've been taking these drugs, and may be greater if you're also having steroid treatment or have diabetes. However, it's still extremely rare.
Your doctor will review your treatment from time to time to make sure the benefits of the treatment still outweigh the risks. Most specialists limit treatment with oral bisphosphonates to five years (or three years for intravenous zoledronate) to minimise the risks of rare, long-term side-effects. However, some people will need more lengthy treatment.
Effects on other treatments
It's usually fine to take other medicines alongside bisphosphonates, but check with your doctor or pharmacist before starting any new medications.
There's no reason why you shouldn't have vaccinations while you're on bisphosphonates.
Alcohol is unlikely to interact with bisphosphonates. However, heavy drinking is a risk factor for osteoporosis and for having falls so it's recommended that you drink alcohol only in moderation.
Fertility, pregnancy and breastfeeding
Osteoporosis usually affects older people, so there's only limited evidence concerning the use of bisphosphonates by women who are pregnant or breastfeeding.
Bisphosphonates can cross the placenta to the unborn baby and can also pass into breast milk in small amounts. There's no clear evidence that this is harmful to the child. However, as a precaution, it's recommended that treatment with bisphosphonates is stopped at least three months before trying for a baby and while breastfeeding.
What else should I know?
Calcium and vitamin D
It's important to get enough calcium and vitamin D as a lack of these can lessen the effect of bisphosphonates. You may be prescribed a daily supplement of calcium and/or vitamin D.
Oral hygiene and dental treatment
During bisphosphonate therapy you should maintain good oral hygiene and have regular dental check-ups. If you're expecting to have dental work it's usually best if this can be completed before starting bisphosphonates. However, it may not be necessary to stop your bisphosphonates if you do need dental treatment later on. If in doubt, check with your doctor.