Strontium Ranelate: Should you start taking it?

We recently reported on a study that found encouraging results for patients taking a nutritional supplement called strontium ranelate for knee problems. The supplement is also used by women with osteoporosis, in the hope that it can strengthen bones and build bone density.

The European study causing all the recent buzz was the Strontium Ranelate Knee Osteoarthritis Trial, where researchers gathered 1,683 people with severe knee problems and gave some of the participants strontium ranelate for treatment while the others were given a placebo.

The researchers looked at x-rays and also used computer software to gauge the level of improvement of each participant's knee.

The study found that those who took strontium ranelate  (brand name Protelos) had improved  physical function and less physical pain, and had less joint damage compared to those who took the placebo.  

The study authors said the safety profile of strontium ranelate is well established, with more than 10 years of experience in the treatment of osteoporosis. The only major contraindication to therapy is deep-vein thrombosis, said Jean-Yves Reginster, MD, of the University of Liège in Belgium, lead author of the study.

Kathryn Dao, MD, director of Clinical Rheumatology at Baylor Research Institute in Dallas, Texas, said that these results are important "since we are so limited in therapeutic options for osteoarthritis (OA)," according to a recent Medscape article. But she said further study is needed before strontium ranelate can be established as a treatment option for knee OA.

"Strontium ranelate seems to have a good side effect profile that is different from narcotics and NSAIDs [nonsteroidal antiinflammatory drugs], which are used to treat the pain of knee OA," she said.

Not approved

It's important to note that the study looked at Protelos, the drug manufactured by the French company  Servier, which has not been submitted to the U.S. Food and Drug Administration (FDA) to be approved for use in the United States, even though it is registered as a prescription drug in more than 70 countries for the treatment of post-menopausal osteoporosis to reduce the risk of vertebral and hip fractures. 

The lack of FDA approval doesn't mean Protelos -- or, to be more precise, an unregulated nutritional supplement version -- isn't available in the U.S. Like so many other  substances not approved as drugs, it is being widely sold as a nutritional supplement, often accompanied by claims that may be dubious.

Nutritional supplements are only lightly regulated and may not be as potent or as pure as commercial medications with similar ingredients. They also are not required to be proven efficacious -- meaning there is no guarantee they will actually help cure or prevent disease.

In Europe, the equivalent of the FDA -- the European Medicines Agency (EMA) -- has completed a review of Protelos and has confirmed a positive benefit-risk balance but it has also warned of newly-found side effects that call for caution by physicians and their patients. 

Lots of side effects

The EMA cited the results of a study conducted last year in France, which found  844 side effects associated with strontium ranelate--nearly 200 of them considered severe by the researchers.

Among the patients that were studied by the research team, 52 percent suffered cardiovascular issues, 26 percent had side effects related to the skin, 6 percent had hepatodigestive problems, 5 percent had neurological side effects, 3 percent had osteomuscular and blood problems and 3 percent suffered from other side effects that weren't listed in the study.

Most of the cardiovascular side effects were related to blood clots, and this occurred in one out of every 31,052 patients, the study found. Among those who suffered from skin-related side effects--which was one out of 13,725--many experienced skin rashes that ranged from moderate to severe.

Some who had hepatodigestive side effects suffered from hepatitis and pancreatitis, both potentially serious problems, while those patients with neurological side effects experienced confusion and amnesia.

The researchers also reported seven deaths that were linked to strontium ranelate and three of those deaths were caused by pulmonary embolisms and related problems that fall under the DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms) syndrome umbrella.

Similar side effects have been reported to the FDA according to Drugcite.com. 

No consensus

Strontium has its fair share of critics, but there remain many in the medical community who say the drug is useful for treating osteoporosis.

There is certainly a need for a more effective osteoporosis and osteoarthritis treatment. According to the Centers for Disease Control and Prevention (CDC), eight out of 100 (7.94 percent) adult women have been diagnosed with osteoporosis, and 19.8 percent of them said the disease was linked to their family history. 

Also, women who reported having bone disease in their families were  2.4 times more times likely to get it themselves, compared to those who don't have the disease in their families.

The CDC also says that women 35 years or older who have at least two relatives with osteoporosis are 8.5 times more likely to develop the disease themselves.

Arthritis, meanwhile, is the most common cause of disability, and osteoarthritis is the most common form of arthritis, the CDC says, affecting more than 27 million Americans.

"This serious, painful and potentially life-altering joint disease places severe limits on daily activity and quality of life for over 27 million Americans," according to the CDC. "In view of the fact that the U.S. population is aging and obesity is on the rise, the prevalence, health impact and economic consequences of OA are expected to increase dramatically."

What to do?

So where does this leave someone who has osteoporosis or knee problems?

While strontium ranelate hasn't been approved by the FDA for the treatment of osteoporosis or knee damage, it is readily available as a nutritional supplement. This is because, like so many nutritional supplements, it is a naturally-occurring substance and thus can be sold so long as it is not marketed as a medicine and does not make unsupported health claims.

Any decision about taking strontium ranelate -- or any other nutritional supplement -- is one that should only be made in consultation with your physician. There are very definite contraindications -- situations in which strontium ranelate may cause harm. You should review these with your doctor -- and ignore all advertising claims -- before making a decision. 

To put it even more plainly: Talk to your doctor before you start taking strontium ranelate or any other drug or supplement. Never base such a decision on a news story or advertisement. The results of early studies are often contradicted over time.  Side effects may be more severe than expected and the results may not be as positive as early findings suggest.