Herbal Heartache: New Review Reminds Cardiologists to Query Supplement Use

Shelley Wood

February 02, 2010

February 2, 2010 (Washington, DC) — The rising popularity of herbals and supplements in Western countries has become increasingly worrisome for physicians who have not traditionally thought to ask their patients whether they are taking any nonpharmaceutical products, despite the often potent effects of certain supplements and vitamins, a new review concludes [1].

Writing in a "state-of-the-art" paper published online February 1, 2010 in the Journal of the American College of Cardiology, Dr Ara Tachjian (Mayo Clinic, Rochester, MN) and colleagues note that more than 15 million people in the US alone take herbal remedies and/or vitamins at doses that might be interacting with their cardiovascular medications, potentially putting them at risk.

"What we have published is nothing new," senior author on the paper, Dr Arshad Jahangir (Mayo Clinic, Scottsdale, AZ), told heartwire , but the messages are worth repeating. "We need to understand the interactions between the medicines that our cardiovascular patients are taking and these herbal products and food supplements that we are often not even aware of when we are visiting with our patients. We need to take a more proactive role in asking patients whether they are taking these complementary and alternative types of therapies."

General Desire for Health Can Lead to Harm

As Jahangir explained, the paper had three aims. First, he said, the authors wanted to highlight the increasing use of supplements and other "alternative" therapies. Visits to complementary and alternative medical practitioners now "far exceed" those to primary physicians, adding up to more than $34 billion in costs, which are typically out of pocket, the authors note. Driving that trend are multiple factors, including the obesity epidemic; anxiety, depression, and pain disorders; a "general desire" for better health and disease prevention; and last, a pervasive notion that complementary and alternative therapies are safer than prescription medications, the authors write.

The second and primary focus of the paper is on some of the most common herbal remedies known to interact with the heart or cardiovascular drugs, including St John's wort, motherwort, ginseng, ginkgo biloba, garlic, grapefruit juice, hawthorn, saw palmetto, danshen, echinacea, tetrandrine, aconite, yohimbine, gynura, licorice, and black cohosh. "We couldn't be too comprehensive, we just picked a few of the most important interactions," Jahangir explained.

He pointed to comprehensive press coverage of grapefruit juice and its inhibitory effect on certain liver enzymes, potentially intensifying drug levels of statins and certain transplant medications. Despite the news splash, he said, grapefruit-juice–drug interactions are extremely common, and physicians might not be reminding patients about them. By contrast, he noted, something like St John's wort actually increases enzyme activity, blunting the effects of medications, notably rhythm-control drugs and transplant medications. "There have been reports of rejection of transplant organs because of reduced protection from immunosuppressive therapy," he said.

Asked if there are any supplements that he thinks have become particularly trendy or troublesome, Jahangir pointed to garlic.

What we are asking for is more scientific evidence . . . before we allow anyone to persuade us to put something in our bodies that can potentially harm us.

"Garlic is a good example of something believed to have immune-modulating effects for infection or an effect on vascular biology--a cholesterol-lowering effect and an antiatherosclerosis effect. But garlic can increase the risk of bleeding in patients who are taking [warfarin]. You can have a scenario in which someone has had an acute MI, receives a stent, and is put on aspirin and clopidogrel, so the risk of bleeding is already high. If the same patient has atrial fibrillation or a mechanical valve and is also taking warfarin, then the risk with garlic, which seems such an innocent thing, may not be as benign, and life-threatening bleeding can occur."

The third focus of the paper is on the lack of regulatory oversight in the herbal-supplement arena. Products marketed as supplements or complementary medicine do not have to go through the same rigorous safety and efficacy tests required of pharmaceuticals, the authors point out. Moreover, no regulatory oversight, quality control, or regulations governing how they are marketed and promoted exist.

Jahangir hopes that increased awareness of potential drug-supplement interactions will motivate policymakers to regulate these products to protect patients' health and their finances.

"Some of these products are very expensive," he said. People paying for them out of pocket may be doing so in an effort to 'take care of their own problems' rather than seeking medical attention, something he said can often lead to critical diagnosis delays.

"The main thing is that the public needs to be more aware of these interactions, and we [as physicians] need to have more communication with our patients. In no way are we saying that these herbs and compounds don't work. What we are asking for is more scientific evidence, in the same way that other compounds and drugs are tested, before we allow anyone to persuade us to put something in our bodies that can potentially harm us."

The authors report no relevant financial conflicts of interest.


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