Understand the Risks Associated with Herbal Supplement Interactions

The use of patient-selected herbal supplements has increased in recent years. With the implementation of the 1994 Dietary Supplementation Health Education Act, the FDA relinquished the right to oversee those products defined as a dietary supplement, explained Julia Baldwin, an intensive care unit nurse who also teaches critical care education, at yesterday's session, "Herbals and Medications: Common Interactions."

To open her session she presented attendees with the following situation to consider: "You are getting ready to discharge a 53-year-old patient with a post-coronary stent. The discharge prescription includes clopidogrel and aspirin. Upon reconciling her home meds, you find out that she takes black cohosh, St. John's wort and ginseng. What do you tell her?"

If they did not already know the answer, attendees were about to find out.

Safe Supplements

Approximately 40% of senior citizens use herbal supplement and are the leading consumers of these products, Baldwin said, adding that college-educated females age 40 and older are the most common users. In the year 2000, $5.8 billion was spent on herbal supplements, and totals have increased since then, she said.

But the misconceptions regarding these supplements are plentiful and patient education is necessary in order to be certain that these products are being used properly.

"You might think they are safe because they are labeled 'natural,'" she said. "Some may actually contain an active ingredient or contaminant that can harm you."

If patients are interested in using these products, inform them to be honest with healthcare providers regarding what supplements they are taking. They should be sure to purchase their products from a reliable source and check labels to ensure the product does not contain any hidden ingredients.

"Unless [manufacturers] do it voluntarily, they do not have to be tested," Baldwin said. "So you might have 10% of the product in the bottle. You might have 100% of the product in the bottle."

Additionally, one in 10 herbal products may be contaminated with heavy metals or pesticides, she cautioned. To be certain that the supplements are safe, patients should look for a United States Pharmacopeia (USP) or a National Formulary (NF) marking which indicates that those products have undergone testing voluntarily.

Common Interactions

Patients and providers need to be aware of the interactions these supplements have with prescription medications they are taking. Among her dozens of examples, Baldwin reported that black cohosh - which is commonly used for hormone balancing, relieving symptoms of rheumatism and lowering lipids - carries risks for patients with a personal or family history of cancer, adolescents and pregnant women. Chamomile, feverfew, garlic, ginko biloba, ginger and red clover are all linked to harmful interactions when used by patients taking anticoagulants. St. John's wort, one of the most well-known herbal supplements, interferes with the actions of "every drug available," Baldwin said.

As for Baldwin's hypothetical 53- year-old patient, "You need to let her know… there is a significant chance you're going to increase the anticoagulant effect," she said.