Ginseng Reduces Effects of Blood-thinning Drug

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Was published at MedlinePlus:

http://www.nlm.nih.gov/medlineplus/news/fullstory_18753.html

 

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Reuters Health

 

By Anthony J. Brown, MD

 

Monday, July 5, 2004

 

 

NEW YORK (Reuters Health) - Patients being treated with the blood-

thinning drug Coumadin (warfarin) should probably avoid using

ginseng, as the popular herb seems to reduce the drug's effects, new

research indicates.

 

Among other indications, Coumadin is often given to patients with an

irregular heartbeat called atrial fibrillation to reduce the risk of

blood clots and stroke. A blood test called the INR is measured on a

regular basis to ensure that the dose being given is not thinning the

blood too much or too little.

 

" The first evidence of a possible interaction between ginseng and

(Coumadin) came from a widely cited case report published in 1997, "

study author Dr. Chun-Su Yuan, from The University of Chicago, told

Reuters Health. In that report, a patient on Coumadin " experienced a

significant drop in the INR after using ginseng for 2 weeks. When the

ginseng was stopped, the patient's INR returned to the desired

level. "

 

Still, Yuan said that some subsequent studies in humans and animals

have not supported an interaction between the two agents.

 

To clarify the association, Yuan's team conducted a study involving

20 healthy volunteers. In the 4-week study, the subjects took

Coumadin during the first week, took American ginseng or placebo for

the second and third weeks, and then took Coumadin during the fourth

week.

 

The researchers' findings appear in the Annals of Internal Medicine.

 

In agreement with the case report, ginseng use for two weeks was tied

to a significant reduction in the INR, meaning that the blood was now

less thin and more prone to clotting.

 

Yuan said that past studies may have failed to show a drug

interaction because ginseng was not used long enough. " One week of

ginseng therapy is probably not enough to " turn on the liver enzymes

that break down Coumadin -- the apparent reason why the herb and the

drug interact.

 

Yuan favors not using ginseng at all for people on Coumadin

treatment. When people take ginseng and the Coumadin dose is adjusted

to compensate, " it's possible that the INR could go dangerously high

if the patient suddenly stops the ginseng. "

 

SOURCE: Annals of Internal Medicine, July 6,2004.