Herb-Drug Interactions Uncommon

[Guest guest]

Herb-Drug Interactions Uncommon

Study Shows Few People Taking Dangerous Combos

By Ann Edmundson, MD

WebMD Medical News

Reviewed By Salynn Boyles

on Thursday, May 25, 2006

May 25, 2006 – St. 's wort, ginkgo biloba, black cohosh. Just a

decade ago most Americans would not have known these names. Today,

these and other herbal medications are not only familiar, but the

products are fixtures on drugstore shelves.

Herbal remedies are not just for health food stores anymore. The

medications have gone mainstream, and as sales continue to rise, so

do concerns about their interactions with prescription and more

traditional over-the-counter drugs.

But new research suggests that potentially dangerous interactions may

occur less often than are widely believed. Investigators reviewed the

drugs taken by 7,652, mostly older Canadians, and found very few

instances of such interactions.

The findings are to be presented tomorrow in Alberta, Canada, at the

North American Research Conference on Complementary and Integrative

MedicineIntegrative Medicine.

Troubling Combinations?

The study included women and men with osteoporosisosteoporosis

enrolled in an ongoing Canadian bone- loss trial. At a five-year

follow-up, the average age of the study participants was 70. Just

over two-thirds of the participants were female.

Researchers collected detailed data on the prescription, over-the-

counter, and herbal drugs taken by the participants. Potentially

dangerous drug-herbal interactions were analyzed for people taking

the heart drugs Lanoxin, Lasix, and Coumadin, as well as

antipsychotic and depressiondepression drugs like Xanax, lithium,

Nardil, and selective serotonin reuptake inhibitors (SSRI), such as

Prozac and Paxil.

Analysis of these data revealed that just 1.3% of the study subjects

were taking combinations of prescription drugs and herbal products

that are considered potentially dangerous.

Of the 514 study participants taking a cardiovascular drug, just 13

(2.5%) were also using a contraindicated herbal medication. And only

one of the 514 participants taking one of the other prescriptions

drugs of concern was also taking an herbal medication identified as

potentially dangerous.

Of the 10 interactions seen among people taking the heart drug

Lanoxin, nine involved the herbal supplement senna, which is found

primarily in over-the-counter laxatives. Only one person taking the

blood thinner Coumadin was also taking a contraindicated herbal

supplement (ginkgo biloba).

Awareness of Risks

Awareness of Risks

Researcher Vik tells WebMD that she expected to see more

potentially harmful drug-herbal supplement interactions among the

patients in the study. Vik is a graduate student in epidemiology at

the University of Calgary.

" We know that quite a few people are using all of these drugs, but it

doesn't look like a lot of people are using the dangerous

combinations, " she says. " This may be due to increased awareness of

the potential risks among consumers and their physicians. "

Of all the currently available herbal medications, the popular

antidepressant alternative St. 's wort has received the most

attention from investigators concerned about drug interactions.

A 2003 study showed that the herb can reduce the effectiveness of as

many as half of all prescription and over-the-counter drugs,

including heart drugs, seizure drugs, depressiondepression and

anxiety drugs, and even oral contraceptives.

In 2000, University of Texas Southwestern molecular biologist

Kliewer, PhD, and colleagues concluded that St. 's wort does this

by activating protein receptors in the liver known as CYP3A4, which

regulate the oxidation of most drugs.

Kliewer tells WebMD that researchers began studying the herbal

product after physicians started seeing evidence of interactions

among their patients who were also on prescription drugs.

Surveys suggest that most patients still do not tell their doctors or

pharmacist about the herbal supplements they take. Kliewer says it is

critical that they do so to minimize the risk of interactions.

" People who take any dietary supplement should tell their doctor

about it, " he says. " These are medicines, and people should treat

them as such. "

http://www.webmd.com/content/article/122/114872?src=RSS_PUBLIC