Taking Supplements? Tell Your Doctor

Your Doctors Need to Know About Your Supplement Use, Experts Say

Medically Reviewed by Louise Chang, MD on October 13, 2006

Oct. 13, 2006 -- If you're taking prescription medicines, you may be overdue to tell your doctor about any dietary supplements you're taking.

Many people taking prescription drugs haven't told their doctors that they also use dietary supplements -- and that may be risky business, in some cases.

So say Paula Gardiner, MD, and colleagues in the Archives of Internal Medicine.

Gardiner works at Harvard Medical School's division for research and education in complementary and integrative medicineintegrative medicine.

The researchers encourage health care providers to "regularly ask their patients with chronic conditions and prescription medications about nonvitamin dietary supplement use."

But patients needn't wait for the doctors; they can broach the topic themselves.

The goal is to make sure your doctors know about all of the things you take -- including supplements -- so they can help you safeguard and enhance your health.

Supplement Study

Gardiner's team studied data from a 2002 national health survey of more than 31,000 U.S. adults.

The survey listed 35 nonvitamin dietary supplements including fish oil; St. John's wort; melatonin; ginseng; glucosamine and chondroitin; echinacea; and ginkgo biloba.

Participants were asked if they had used "natural herbs" for their own health or treatment in the past year.

They were also asked if they had told their doctor about any use of nonvitamin dietary supplements, and whether they had taken any prescription drugs in the past year.

About two-thirds had taken prescription drugs in the previous year.

Twenty-one percent of those participants had taken supplements at some point during the previous year, compared with 16% of people who hadn't taken prescription drugs in the past year.

Among prescription drug users, the most commonly used supplements included echinacea, ginseng, ginkgo, and garlic, the researchers note.

According to Gardiner's team, an estimated 135 million people in the U.S. used prescription medicines in the previous year.

Prescription Drugs, Supplement Use

Nearly 70% of participants who reported taking prescription drugs and supplements at some point in the past year said they hadn't told their doctors about their supplement use.

"In general, prescription medication users with chronic but not life-threatening conditions (menopausemenopause, chronic gastrointestinal conditions, headaches, and insomniainsomnia) tended to have high nonvitamin dietary supplement use," the researchers write.They add that "those with chronic and life-threatening conditions (cardiovascular disease, strokestroke, and diabetesdiabetes) had the lowest rates of nonvitamin dietary supplement use."

Women and people with higher education levels were among those who were more likely to have used prescription medicines and supplements at some point in the past year.

It's not clear whether participants had used supplements and prescription drugs at the same time.

What's the Big Deal?

The researchers aren't bashing supplements. But they do see some potential risks with certain supplements and prescription drugs.

"Many of the herbs and dietary supplements asked about in the [survey] such as chamomile and peppermint are safe for consumption," note Gardiner and colleagues.

But the list also included several supplements that are "known to have well-documented drug-herb interactions," the researchers write.

For instance, they point out that St. John's wort can affect the blood levels and/or sway the effects of several drugs, including birth controlbirth control pills.

Ephedra and kava kava have also been linked to certain drug interactions, according to Gardiner and colleagues.

They write that more research on drug-herb interactions is "critically needed."

Talk to Doc

The National Center for Complementary and Alternative Medicine (NCCAM) offers this advice on its web site:

  • Talk to your health care provider about complementary and alternative medicine therapies before making any decisions about treatment or care.
  • Tell your health care provider about any complementary and alternative therapies you use.

"This is for your safety and so your health care provider can develop a comprehensive treatment plan," states the NCCAM's web site.

The NCCAM is part of the National Institutes of Health (NIH).

Show Sources

SOURCES: Gardiner, P. Archives of Internal Medicine, Oct. 9, 2006; vol 166: pp 1968-1974. National Center for Complementary and Alternative Medicine: "Get the Facts: Are You Considering Using Complementary and Alternative Medicine (CAM)?"
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