Bisphosphonates are a group of medicines used to treat conditions that affect your bones, such as osteoporosis and Paget's disease.
- Osteoporosis is a condition that causes your bones to be weaker than normal. This means that they can break (fracture) easily, such as after a small bump or fall. If you have osteoporosis, bisphosphonates can be used to prevent bone loss, increase bone thickness and lower your risk of spine and hip fractures.
- In Paget's disease, the growth of abnormal bone causes deformity and pain. Bisphosphonates can help with this.
- Bisphosphonates may also be used to reduce the high levels of calcium in your blood (called hypercalcaemia) associated with some cancers.
Examples of bisphosphonates
There are many bisphosphonates available in New Zealand. Some are available as tablets, whereas others are given by injection as a drip into a vein (called intravenous infusion).
Each bisphosphonate has different uses and side effects. Which bisphosphonate is best for you depends on your health and the condition being treated. Your doctor will advise you on the best bisphosphonate for you.
|Examples of bisphosphonates available in New Zealand|
Bisphosphonate tablets may not be suitable if you have problems with your stomach, swallowing difficulties or are unable to stand or sit upright for longer than 30 minutes.
How do I take bisphosphonate tablets?
Bisphosphonate tablets are taken once a week (on the same day of the week) if they are being prescribed for osteoporosis. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.
Take bisphosphonate tablets on an empty stomach.
- Take your bisphosphonate dose first thing in the morning at least 30 minutes before you eat or drink anything. If you take a bisphosphonate with food, or drinks other than water, only a small amount of the medicine is absorbed.
- Swallow the tablet with a full glass of water and sit upright for 30 minutes afterwards. This is because bisphosphonates can irritate your oesophagus (the tube that takes food and drink from your mouth to your stomach) and give you reflux or indigestion.
Having zoledronate injection
Zoledronate injection is given as a drip (infusion) into a vein, which takes about 15–30 minutes. For osteoporosis, zoledronate infusion is usually given once every 18–24 months for a total of 3 infusions. Before having a zoledronate infusion, you will need blood tests to check the calcium levels in your blood and how well your kidneys are working. You may also need to take vitamin D supplements (see below). After the infusion, you may have to stay at the clinic or doctor's surgery for observation, in case of any unwanted reaction.
Note: While in most cases the medication (zoledronate) is subsidised by the government and is free or low cost, the cost of the infusion (giving you the injection) is not. GPs will charge for this service and can set their own fee. Read more about zoledronate.
Vitamin D and calcium supplements
While taking bisphosphonates you need to get enough calcium and vitamin D.
Getting about 5–10 minutes of exposure to sunlight 4–6 times per week can prevent vitamin D deficiency and therefore avoid the need for supplements. Vitamin D supplements such as colecalciferol is usually reserved for frail older adults. Read more about colecalciferol.
It's best to get calcium through your diet. Recommended intake levels are 500–1300 mg daily, which is about the amount found in 2–3 cups of milk or 4–6 slices of cheese per day. Read more about calcium supplements.
The effects of bisphosphonates are not immediate
After starting your bisphosphonate, it may be a few months (6–12 months) before there is an increase in your bone density. This will help to prevent breaks (fractures) of your hips and other bones, such as your wrists. But you may still have a fracture while you are taking a bisphosphonate – they do not totally reduce your risk. They usually need to be taken for some years to see the full effect.
What are the side effects of bisphosphonates?
Like all medicines, bisphosphonates can cause side effects, although not everyone gets them.
Problems with your jaw
Bisphosphonates can cause osteonecrosis of the jaw. This can be caused by delayed healing in your mouth after some dental procedures. It is quite rare. To reduce the risk of this problem, it is best to:
- take good care of your teeth and mouth (such as brushing your teeth twice a day and regular flossing between your teeth)
- have regular dental check-ups
- have any dental treatment you need completed before you start taking a bisphosphonate
- let your dentist know that you are having bisphosphonate treatment
- talk to your doctor or dentist if you have any loose teeth or tooth pain, or swelling or numbness in your jaw.
Bisphosphonates can rarely cause fractures in your thigh bone (upper leg bone). These are called atypical fractures because they appear as cracks on the bone and are not usually related to an injury. If you have pain, weakness or discomfort in your thigh, hip or groin, tell your doctor. These pains may be warnings that there is some weakness in your bones. You may need x-rays of your legs to be sure.
Other side effects
|Side effects||What to do|
|Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product|
The following links provide further information on bisphosphonates. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.
- Bisphosphonates New Zealand Formulary
- Bisphosphonates: addressing the duration conundrum BPAC, NZ, 2019
- Osteoporosis treatments and atypical femur fracture Medsafe, NZ, 2013
- Osteonecrosis: A Pain in the Jaw Medsafe Prescriber Update 33(2): 13-14 June 2012
- Osteonecrosis Of The Jaw And Bisphosphonates - Putting The Risk In Perspective Medsafe Publications, October 2007
- Reminder: Keeping an eye on bisphosphonates Medsafe Prescriber Update 32(3): 24 September 2011
- An update on bisphosphonates BPAC, NZ, 2014
Additional resources for healthcare professionals
Alendronate - risk of low-energy femoral shaft fracture Medsafe, NZ, 2009
Zoledronic acid - safe prescribing - bone up SafeRx, NZ, 2015
Risedronate now fully subsidised – what is its place in practice? BPAC, NZ, 2013