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Bisphosphonates are a group of medicines used to treat bone disease such as osteoporosis and Paget's disease.

  • Osteoporosis is a condition that causes your bones to be thinner and weaker than normal. This means that they can break (fracture) easily, such as after a small bump or fall. In osteoporosis, bisphosphonates prevent bone loss, increase bone thickness and lower your risk of spine and hip fractures.
  • In Paget's disease, the formation 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 the blood (called hypercalcaemia) associated with some cancers.

Examples of bisphosphonates

There are a variety of bisphosphonates available in New Zealand. Some are available as tablets, to be taken by mouth, and others are given by injection, as a drip into the vein (called intravenous infusion).

Each bisphosphonate has different uses and side effects. Which bisphosphonates 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

How to take bisphosphonates?


Alendronate, etidronate and risedronate are taken either once a day, once a week (on the same day of the week), or once a month (on the same day of the month), depending on the one prescribed. 

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:

  • Most people take their bisphosphonate first thing in the morning before they 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.
  • This is why you need to wait between 30 minutes and 2 hours before eating or drinking anything (other than water). The information leaflet that comes with your tablets will tell you exactly how long you should wait.
  • You need to swallow the tablet with a full glass of water and sit upright for 30 minutes afterwards. This is because bisphosphonates can irritate the upper part of your gut (oesophagus - the tube that takes food and drink from your mouth to your stomach.)


Bisphosphonate injections are given as a drip (infusion) into the vein, once a year or every 3 months depending on the type prescribed and the condition being treated. 

The infusion will take between 15 minutes and 4 hours. After the infusion, you may have to remain at the clinic or doctors surgery for observation for at least one hour, in case of any unwanted reaction.

Possible side effects

Like all medicines, zoledronic acid can cause side effects, although not everyone gets them.

Osteonecrosis of the jaw

This is a problem with the jaw, where there is delayed healing in the mouth following some dental procedures. This is extremely rare. It is advisable to:

  • Maintain good hygiene and care of your teeth and mouth (such as brushing your teeth twice a day and regular flossing between your teeth).
  • Receive regular dental check-ups.
  • If you need any dental treatment, it is recommended that you have this done before receiving your zoledronic acid infusion. 
  • Let your dentist know that you are receiving treatment with a zoledronic acid.
  • Talk to your doctor or dentist if you experience loose teeth, tooth pain, or swelling or numbness in your jaw. 

Other side effects

Side effects What to do
  • Difficulty swallowing or pain when swallowing
  • Heart burn or indigestion
  • Bloating (gas in the stomach)
  • Nausea (feeling sick)
  • Diarrhoea (loose stool)
  • Bisphosphonate tablets can cause inflammation of the gut resulting in these side effects
  • Tell your doctor if troublesome
  • Flu-like symptoms such as muscle and joint pains, fever, headache
  • Irritation or burning at the site of the injection 
  • These symptoms are quite common with bisphosphonate injection. These symptoms tend to go away after a few days.
  • Your doctor can recommend a mild pain reliever such as ibuprofen or paracetamol to reduce these side effects.  
  • Tell your doctor if troublesome
  • Eye pain
  • Red eye
  • Changes in your vision
  • Sensitive to light
  • Floating spots in your vision
  • These symptoms are related to inflammation in the eye. This is quite rare.
  • Contact your doctor immediately if you experience these symptoms.

Learn more

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 (tablets) Australian Rheumatology Association
Bisphosphonates (intravenous/IV) Australian Rheumatology Association
Bisphosphonates Patient Info, UK