Strontium ranelate (Protos) for post-menopausal osteoporosis

Published in Medicine Update

Date published: About this date

Health and medicines information in this article may have changed since the date published. This information does not replace advice from a health professional.

This Medicine Update is for people who are taking strontium ranelate or are thinking about starting it.


When you are considering a new medicine, it is important to weigh up the expected benefits and the possible risks of the new medicine, compared with other available medicines or treatments.

Remember that risks and benefits differ between medicines and from person to person.

Your doctor can help you compare different medicines and treatments to decide what is best for your particular situation.


What strontium ranelate is

The active ingredient is strontium ranelate and the brand name is Protos.

It is pronounced STRON-tee-um RAN-ell-ate, or PRO-toss.

It comes as a powder that you dissolve in water and take once a day.

What strontium ranelate treats

Strontium ranelate treats osteoporosis.

Osteoporosis is a condition which causes bones to become fragile and brittle. If you have osteoporosis you are at risk of fractures (broken bones), most commonly in the hips, spine (backbone) and wrists. These fractures can cause long-term pain and the loss of independence.

Osteoporosis is more common in women, especially after menopause, but it can occur in men. Osteoporosis may also be caused by long-term use of some medicines, such as prednisolone, that are used for asthma and some rheumatic conditions.

Osteoporosis medicines are most useful for people who have a high risk of fracturing their bones. People who have already had a fracture have the greatest risk of having another fracture. People who are older and have thinner bones (technically known as lower bone mineral density) also have a greater risk of fracturing their bones and can benefit from osteoporosis medicines.

Strontium works by slowing the thinning of the bones and by allowing new bone to rebuild and strengthen. Bone strength is usually measured by a bone mineral density scan, which indicates the amount of calcium in your bones. A bone mineral density scan is also sometimes called a BMD scan or a DEXA scan. This scan is quick and painless, like an X-ray.

A bone mineral density scan measures the density of your bones and compares the result to the bone density of an average young adult. The result is called a T-score. If you have osteoporosis your T-score will be minus 2.5 or lower. A score of minus 3 is lower (worse) than a score of minus 2.5. The lower your T-score the greater your risk of fracture.

Treatment with strontium aims to reduce your risk of fracturing your bones and to increase your bone mineral density.

Who can use strontium ranelate?

Women who have passed menopause (i.e. postmenopausal women) can use strontium ranelate to treat osteoporosis. You can receive strontium which is subsidised by the Pharmaceutical Benefits Scheme (PBS) if:

  • you have already had a fracture due to postmenopausal osteoporosis, or
  • you are 70 or older and have a T-score on your bone mineral density test of minus 3 or lower.

Strontium should not be prescribed to men, or to women who have not passed menopause (i.e. pre-menopausal women). It has not been tested in these groups.

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Other medicines available for this condition

Other medicines apart from strontium ranelate are available in Australia for the treatment of osteoporosis. Talk with your doctor about all of the treatment options. The different medicines work in different ways.

They include:

  • alendronate (Fosamax Plus, Alendro Once-weekly, Alendrobell and Ossmax), etidronate (Didronel,Didrocal) and risedronate (Actonel), which all belong to a group of medicines called bisphosphonates
  • raloxifene (Evista), which has similar effects on bone to oestrogen
  • teriparatide (Forteo), which is a synthetic form of a hormone normally produced by the parathyroid gland (which sits near the thyroid gland in the throat).

Not all of these other medicines are subsidised on the PBS for people with osteoporosis.

Raloxifene can be prescribed through the PBS for postmenopausal women who have had a fracture due to osteoporosis.

Alendronate and risedronate can be prescribed through the PBS for men and women with osteoporosis who:

  • have already had a fracture due to osteoporosis, or
  • are 70 or older and have a T-score on a bone mineral density test of minus 3 or less.

Hormone replacement therapy (HRT), or oestrogen therapy, was once widely used for women with postmenopausal osteoporosis. It is no longer recommended for the sole purpose of reducing the risk of fracture (especially in older women) because of some serious side effects that may happen after long term use.

How well strontium ranelate works compared with other medicines

Alendronate, risedronate or strontium ranelate may all be used by women with postmenopausal osteoporosis. However, because strontium is a newer medicine, doctors and pharmacists have less experience using it and its longterm safety is less established.

Strontium has not been directly compared in the same clinical trial with any other medicine used for the treatment of osteoporosis, so it is hard to say exactly how they compare. All of the trials of strontium have involved postmenopausal women (average age about 74 years). No clinical trials have looked at the effectiveness of strontium for men or premenopausal women.

There are clinical trials that show that strontium reduces the risk of a fracture when compared to a placebo (dummy pill). Other clinical trials show that alendronate and similar medicines also reduce the risk of a fracture compared with placebo. Looking at this research, it seems that strontium reduces fractures in the spine by about the same amount as alendronate for women who have already had a fracture, as well as for women aged 70 and older with low bone mineral density but no previous fracture. There is also some research showing that strontium reduces the risk of fractures in women aged over 80.

There is evidence that alendronate and risedronate may reduce the risk of hip fracture. While there is also evidence that strontium may reduce the risk of hip fracture for postmenopausal women, more research is needed on this question.

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Important side effects of strontium ranelate to consider

Strontium ranelate is a new medicine, so we know little about its long-term side effects and safety beyond five years of use.

Ask your health professional about the possible side effects of this medicine before you take it. Always tell them about any changes to your condition if you're taking a new medicine.

To report possible side effects call the NPS Adverse Medicine Events (AME) Line on 1300 134 237 from anywhere in Australia (Monday–Friday, 9am–5pm AEST).

People with questions about their medicines or seeking general information about side effects can call the NPS Medicines Line on 1300 633 424 (Monday–Friday, 9am–5pm AEST).

The most common side effects of strontium are nausea, diarrhoea, headache and rashes. These usually settle down fairly quickly.

Serious but uncommon side effects include a risk of clots forming in the legs or lungs — women who have had blood clots previously should discuss this with their doctors before taking strontium.

Problems such as memory loss, poor concentration and fits were reported in some clinical trials of strontium, but these were rare.

Strontium may also cause a serious type of allergic reaction involving a rash. If you are taking strontium and develop a rash, you should stop taking the medicine immediately and see your doctor.

For a more complete list of possible side effects for Protos (strontium ranelate), see the consumer medicine information (CMI) leaflet available on our Medicines Finder page.

How the side effects of strontium ranelate compare with other medicines

More is known about the side effects and long-term safety of other treatments for osteoporosis.

Bisphosphonates (e.g. Actonel, Alendro Once-weekly, Didrocal, Didronel and Fosamax Plus) — common side effects of bisphosphonates are:

  • nausea
  • vomiting
  • diarrhoea
  • muscle pain
  • joint pain
  • headache.

Damage to the oesophagus (or gullet) and inflammations of the stomach and digestive system can occur, so taking these medicines when and as directed is important to help prevent these effects.

Less common side effects that can occur are an inflamed tongue or eyes and, rarely, an allergic reaction.

A rare but important side effect of bisphosphonates is damage to the jaw bone, which can come on slowly and may not heal even if the medicine is stopped. Symptoms can vary and include severe jaw pain, numbness, infections, bad breath, sore teeth, denture sore spots, loose teeth and slow healing of cuts or infections. Most cases have occurred in people with cancer taking high doses of these medicines by injection, and the risk in people taking tablets for osteoporosis is relatively small. Taking good care of your teeth and gums may help to avoid this adverse effect.

Raloxifene (Evista) — common side effects of raloxifene are:

Remember that benefits and side effects differ between medicines and from person to person.

  • hot flushes
  • sweating
  • leg cramps
  • fluid retention
  • sleep problems.

A serious side effect is blood clots — if you have had blood clots in the past, you should not take raloxifene.

Teriparatide (Forteo) — the side effects of teriparatide are:

  • nausea
  • headache
  • dizziness
  • leg cramps
  • joint pain
  • high levels of uric acid in the blood (which may make you susceptible to gout).

Hormone replacement therapy (HRT)common side effects of HRT are:

  • nausea
  • headache
  • breast pain
  • vaginal bleeding
  • changes in weight
  • leg cramps.

Women who have not had a hysterectomy have to take another type of hormone — called a progestogen — to help prevent cancer of the uterus, which may occur if oestrogen is used on its own. This combination of HRT increases the risk of blood clots, heart disease, stroke and breast cancer, so it is not recommended for long-term use for osteoporosis.

Oestrogen therapy on its own can also increase the risk of stroke, blood clots and breast cancer. These serious adverse effects of HRT are more likely to occur in older postmenopausal women, mostly over the age of 60 years.

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What else you should know about strontium ranelate

Take strontium at bedtime, at least two hours after last eating or drinking milk. You take it each day. Take strontium by dissolving the powder in at least 30 mL of water (about a third of a glass).

Calcium in food and drink can reduce how much strontium ranelate is absorbed by the body. If you take calcium supplements, tetracyclines (a type of antibiotic) or antacids as well as strontium, you should take them at a different time of day (at least two hours before strontium).Back to top

Who can be prescribed strontium ranelate on the Pharmaceutical Benefits Scheme

If you are prescribed strontium through the Pharmaceutical Benefits Scheme (PBS), you pay only the cost of a normal prescription, and the Australian Government pays the rest.

Strontium is subsidised on the PBS for use by some postmenopausal women with osteoporosis. You are eligible:

  • if you have already had a fracture due to osteoporosis, or
  • if you are 70 or older and have a T-score on your bone mineral density test of minus 3 or lower.

You can only be prescribed one osteoporosis medicine through the PBS at a time. So you cannot be prescribed strontium ranelate through the PBS if you are already taking a PBS-subsidised medicine for osteoporosis.The full cost of each strontium prescription is $52.10. At the time of publication, the cost of a PBS-subsidised prescription was:

  • $31.30 for people without a concession card
  • $5.00 for concession card holders.

Each prescription lasts 28 days, and you can get up to five repeats.Back to top

Other ways to help this condition

A healthy lifestyle — regular exercise, plenty of dietary calcium, some sunshine and no smoking — is important for helping to prevent osteoporosis and to manage it along with your medications.


Exercise maintains bone mass and improves muscle strength and balance. Research shows that weight-bearing exercise such as walking or dancing can help strengthen bones in some people. However the main goal of exercise in people who already have weakened bones from osteoporosis is to improve muscle strength and balance.

Exercises that are recommended if you have osteoporosis include Tai Chi, aquaerobics and hydrotherapy. Improving your muscle strength and balance with these exercises means you may be less likely to fall and break a bone. Avoid high-impact exercises that may break a bone, such as those involving twisting, sit-ups or sudden muscle movements (e.g. lifting weights).

Reducing your risk of falling over may help you to prevent a fracture. Your GP, physiotherapist or occupational therapist can help you assess your risk of falling and advise what you can do to keep yourself safe.

Dairy products

About 3–4 serves of dairy products each day is recommended. A 250 mL glass of milk, a 200 g tub of yoghurt and a 40 g piece of cheese are each one serve. Canned fish, tofu, some beans and some green vegetables also contain good amounts of calcium.

If an adequate daily intake cannot be achieved in the diet, a calcium supplement is needed.

Vitamin D and sunshine

Vitamin D is also important as it helps the body absorb calcium. Sunshine helps your skin make vitamin D – about 15 minutes of sun on your face, arms and hands on most days of the week should be enough, preferably before 10 am or after 3 pm when the risk of sunburn is lowest.

Vitamin D is also found in oily fish such as tuna or mackerel), eggs and liver, and is added to some milks and margarines. The diet is unlikely to provide an adequate daily intake on its own, so people who get little or no sunlight need a vitamin D supplement.

Quitting smoking

Smoking thins your bones – quitting is a good idea. Call the Quitline on 131 848 if you’d like help.

For more information, contact Osteoporosis Australia: on 1800 242 141 for the branch details in your state.

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How new medicines are tested and approved for use in Australia

Prescription medicines go through many tests and clinical trials before they can be prescribed in Australia. All medicines go through four types of tests to assess their effectiveness, side effects and safety:

  • laboratory tests (not involving people)
  • phase 1 clinical trials, typically with 20–80 healthy volunteers, to test the safety and dosage in people with normal physical health
  • phase 2 clinical trials, typically with 100–500 volunteers with the condition, to test the effectiveness and safety
  • phase 3 clinical trials, typically with 1000–3000 volunteers with the condition, to confirm the medicine’s effectiveness and find out more about its side effects.

Sometimes, less common side effects do not become obvious until large numbers of people have used the medicine.

The Therapeutic Goods Administration (Australia’s regulatory agency for medicines) checks clinical trial results before it approves the registration of the medicine for use in Australia.

Medicines are made available on the Pharmaceutical Benefits Scheme if they are shown to be as good as or better than other available medicines for the same condition.

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Where to find more information

You can find more information in the consumer medicine information (CMI) for strontium ranelate (Protos). This will tell you:

  • who should not use the medicine
  • which other medicines should be avoided
  • how to take the medicine
  • most of the possible side effects
  • the ingredients.

You can get the CMI leaflet for Protos from:

Information over the phone

NPS works with healthdirect Australia to provide the NPS Medicines Line phone service for consumers.

To get more information about any medicine call 1300 MEDICINE (1300 633 424). This service is available from anywhere in Australia, Monday to Friday, 9am to 5pm AEST excluding NSW public holidays.

To report a side effect

Call the NPS Adverse Medicine Events (AME) Line on 1300 134 237, Monday to Friday, 9am to 5pm AEST excluding public holidays.

The AME Line is a service where you can report possible side effects of your medicine and contribute to national medicine safety efforts. Information on medicine-related side effects is passed on to the Therapeutic Goods Administration (TGA) for assessment, but your personal details will remain confidential and your privacy maintained.

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