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Dietary supplements may contain potentially harmful active drugs

The tainting of supplements with pharmaceutical ingredients “does not happen by accident and poses a serious public health risk as consumers unknowingly ingest these drugs,” write the authors of the study.

REUTERS/David Gray
The findings of this new study underscore the potential dangers facing the 50 percent or so of American adults who use dietary supplements.
Since 2007, hundreds of dietary supplements — particularly ones used for erectile dysfunction, weight loss or muscle building — have been identified by the U.S. Food and Drug Administration (FDA) as containing actual pharmaceutical drugs, according to a disturbing study published last Friday in JAMA Network Open.

In almost all those cases, consumers had no way of knowing from the products’ labels that the supplements contained pharmaceutical drugs.

The tainting of dietary supplements with pharmaceutical ingredients “does not happen by accident and poses a serious public health risk as consumers unknowingly ingest these drugs,” write the authors of the study.

“Adulterated dietary supplements have the potential to cause adverse health effects both on their own and also in combination with other medications an individual may be taking,” they add.

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Some supplements marketed for weight loss were found, for example, to contain sibutramine, a drug that can increase blood pressure or heart rate, presenting a risk to people with a history of heart disease or stroke. Others contained fluoxetine, an antidepressant that has been associated with such serious side effects as suicidal thinking, abnormal bleeding and seizures. Still others contained phenolphthalein, a laxative drug that was removed from over-the-counter products in the United States almost 20 years ago over concerns that it might cause cancer.

Poorly regulated

The findings of this new study underscore the potential dangers facing the 50 percent or so of American adults who use dietary supplements.

Those dangers are real. Dietary supplements have been known to cause stroke, kidney failure, acute liver injury, pulmonary embolisms and death. About 23,000 Americans end up in hospital emergency departments each year because of the side effects of supplements. About 2,000 of those individuals require hospitalization.

As background information in the current study points out, dietary supplements, which include vitamins, minerals, botanicals, amino acids and enzymes, are not supposed to be used for the treatment or prevention of disease. The government classifies them as a category of food (thanks to the supplement industry’s successful lobbying of Congress). Supplements are not required, therefore, to undergo testing for effectiveness or safety before they go on the market.

Supplement manufacturers are required to tell the FDA each time they receive a report of someone having a serious health-related adverse reaction to one of their products. Doctors also are encouraged to make such reports. The FDA can then investigate and, if the agency deems it necessary, ask a company to voluntary recall the product from the market.

But many problems with supplements go unreported, often because doctors are unaware that a patient is taking a supplement and/or fail to make the connection between the patient’s use of a supplement and an adverse health event.

Over one recent three-year period, poison control centers received more than 1,00 more reports of adverse events associated with dietary supplements than did the FDA.

Looking for trends

The authors of the current study, a team of researchers from the California Department of Public Health, decided to take a closer look at the kinds of dietary supplements that have received warning letters from the FDA for being adulterated with pharmaceutical drugs. One of the things they wanted to determine is whether the problem is getting better or worse.

They found that the FDA had identified 776 dietary supplements as being tainted with pharmaceutical drugs from 2007 through 2016. Those products were marketed by 146 different companies.

Most of the supplements were sold to consumers for sexual enhancement (353), weight loss (317) or muscle building (92). The rest were peddled for a variety of other health purposes, including joint pain, muscle pain, osteoporosis, bone cancer, sleep issues, gout and prostate health.

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In addition to sibutramine, fluoxetine and phenolphthalein, some of the many other drugs found in the supplements included sildenafil (the active ingredient in the erectile dysfunction drug Viagra), tadalafil  (the active ingredient in another erectile dysfunction drug, Cialis), dapoxetine (an antidepressant not approved by the FDA) and dexamethasone (a corticosteroid used to treat inflammatory conditions).

More than 20 percent of the tainted dietary supplements contained more than one active pharmaceutical drug, and two contained as many as six. In more than 97 percent of the cases, those active ingredients did not appear on the supplement’s label.

Amazingly, only 360 of the contaminated products (less than half) were subsequently recalled by the FDA. The agency issued a public warning notification for the others, an action that meant the products could still be purchased and used by consumers.

Of the 443 adulterated products identified in the most recent five years (2012-2016), more than 80 percent received a public warning rather than a recall.

An ‘alarming’ situation

“The agency’s failure to aggressively use all available tools to remove pharmaceutically adulterated supplements from commerce leaves consumers’ health at risk,” writes Dr. Pieter Cohen, a general internist at Harvard Medical School, in a commentary that accompanies the study.

Indeed, 28 of the tainted supplements identified in the study received two or three FDA warning letters at least six months apart.

“Of products that were found to be adulterated more than once, 19 (67.9 percent) had new drug ingredients reported in their second or third warning,” the study’s authors points out. “This indicates that these products continue to be sold and are potentially dangerous even after FDA warnings.”

“This is alarming, especially considering that the FDA is only able to test a portion of products available on the market,” they add.

Meanwhile, American consumers continue their infatuation with dietary supplements, spending more than $30 billion on such products each year.

FMI:  You can read the study and the accompanying editorial in full on the JAMA Network Open website.