Herbal-Drug Interactions

Nutrition Hot Topics - Herbal/Drug Interactions

About 70 million Americans use herbal supplements. While there is a long and well-established tradition of safe use for a variety or herbs, particularly for otherwise healthy individuals, the potential for adverse interactions between herbal products and prescribed drugs, and individuals under a doctor's care, warrants attention.An interaction between an herbal supplement and a drug can result in an increase or a decrease in the pharmacology or toxicology of either the drug or the herb. The drug might produce less of an effect than it is supposed to, a stronger effect than it is supposed to, or it may be that the interaction between a drug and an herb might produce an effect different than expected.

The Lancet review In January 2000, the British medical journal The Lancet presented a review of reports used by medical professionals. 1It noted that sorting drug and herb interactions that can reliably be predicted from those that seem to happen by chance is not an easy task. There are thousands of over-the-counter and prescription drugs on the market -- with new ones being introduced every day-and it is not unusual for people to take combinations of drugs. The result is that testing for interaction among all the possible combinations of drugs is almost impossible, and when herbs are added into the equation, the complexity of the issue takes a quantum leap. The different brands of herbal preparations on the market vary widely in terms of potency, herb combinations, and parts of the plants used. These differences can result in observing an interaction with one product and not with another, though they contain the same herb. The Lancet article, for example, cited a case where a Siberian ginseng product was suspected of causing a certain adverse reaction, but in analyzing the product, it didn't contain Siberian ginseng. The product used Chinese silk vine -- a species unrelated to ginseng -- and was identified as having caused the problem.Interactions reported with enough regularity to warrant attention

St. John's Wort

St. John's wort appears to interact with the class of drugs used to treat depression, known as serotonin re-uptake inhibitors, one of the most popular being Prozac. St. John's wort may interact with a wider range of drugs, including certain AIDS drugs, like the protease inhibitor, indinavir, and cyclosporin, an immunosuppressive drug used by organ transplant patients.Some other drugs that may interact with St. John's wort:

Oral Contraceptive Drugs

Digoxin -- used to treat congestive heart failure.

Theophylline -- used to treat respiratory disorders.

Phenprocoumon - an anti-clotting drug.

Gingko Biloba

Ginkgo biloba may interact with blood-thinning compounds such as heparin, aspirin, or warfarin, known by the brand name, Coumadin. Ginkgo biloba may intensify anti-clotting effects of drugs because it, too, has anti-clotting properties. Individuals taking these types of drugs may want to avoid using ginkgo biloba. Anyone with an upcoming surgical procedure should consider discontinuing ginkgo biloba well before the surgery.

Garlic, ginseng, dong quai, and ginger also may interact with anti-clotting drugs.

Vitamins & Minerals

Some nutrients in high doses can intensify the effect of blood-thinning drugs. They include vitamin E and the omega-3 fatty acids from fish oil, and the same precautions should be taken with these nutrient supplements as with the herbs that potentially interact with blood-thinning compounds.

Vitamin K

Anyone taking anti-clotting drugs, such as Coumadin, should let the prescribing physician know about changes in diet or dietary supplements that affect vitamin K intake. Vitamin K enhances the potential for increased clotting.

Laxatives & Dietary Fiber

Laxatives and bulk-forming agents like dietary fiber speed up intestinal transit time. Thus, they could theoretically impact the uptake of drugs that are absorbed in the intestines.

Soy Protein

A potential interaction exists between synthroid and soy protein. Some case reports have noted infants on synthroid have difficulty achieving a stable dose when being fed a soy-based infant formula. Soy may cause a decrease in the absorption of the medication. A few similar cases with adults have also been reported. It is recommended that individuals taking synthroid take the medication and soy protein at separate times.

General notes about combining herbs and drugs

Anyone taking prescription medications along with herbs -- or considering doing so - should let their physician know. Even if the doctor doesn't know much about herbs, the doctor will be alerted for possible interactions. This would provide valuable clues also to help the physician figure why a medication might not be working as expected. This is even more important for someone who is taking a life-sustaining medication. Pregnant and nursing women should talk with their doctor about their use of herbs also. Informing the doctor is extremely important because surveys have shown that most people taking herbs and vitamin supplements do not tell their doctors about it. Doctors really need this information to accurately monitor specific treatments. Summary

The herbs in Shaklee dietary supplements have been selected because of their history of safe use. Even so, herb-drug interactions can occur, and there are so many potential combinations of herbs and drugs that it's impossible to test and identify all the conceivable interactions. The best way to prevent potential problems is to let the physician know what herbal and nutritional supplements are being used or considered for use. This will allow the physician to monitor the patient more closely and note if the herbal supplements create any complications in conjunction with any of the medicines being taken. 1Fugh-Berman A. Herb-drug Interactions. Lancet 2000; 355:134-38.

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© Copyright 2001 Shaklee Corporation. All rights reserved.

Date: Thu, 18 Apr 2002 20:05:06 -0000
Subject: prescription drugs - $$ to influence doctors

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - From free samples of drugs to tickets to ball games, most doctors in the United States say they have received a giveaway from a drug company, according to a survey released on Tuesday.

Virtually all get free samples of drugs, and 61 percent say they have received meals, tickets to events, or free travel, according to the survey by the Kaiser Family Foundation, a nonprofit group that researches health and family issues.

Drug companies spend far more on spending to influence doctors than on research and development, or even on advertising to consumers, the foundation found.

"It is an issue that raises concern and that warrants real public scrutiny because you have got commercial interests trying to influence the behavior of doctors and patients," said foundation President Drew Altman.

What is not clear is how much these perks influence doctors, Altman said. "It requires a close look," he said, adding that he plans more studies on the subject.

"It's bad because it undoubtedly drives up health-care costs and because some people will get drugs they don't need, and it is potentially good because some people will get drugs that they need."

Altman said it will be hard to measure actual influence, although clearly the drug companies believe they are influencing doctors or else they would not spend so much trying.

"I have a really hard time believing that any physician would ever prescribe a drug because he or she is being influenced by drug companies when they felt it was not in the patient's interest," he said.

"The problem is that a lot of medical situations are very gray and that is where influence can come in."

DOCTORS KNOW DRUG COMPANIES WATCH THEM The survey found that most doctors are aware the drug companies keep track of what prescriptions they write, and about a third are very bothered by this.

"They know the drug companies are monitoring them. They know the drug companies are trying to influence them," Altman said. "But when you talk to physicians anecdotally, they just shrug it off and laugh. They say 'I am enjoying the free vacation but I am not affected by it."'

Kaiser surveyed more than 2,600 doctors across the country for its report, which found only 12 percent said they got financial incentives to participate in drug trials.

But drug companies try other routes to get a doctor's attention -- from giving them pens, medical equipment and reference material embossed with a drug's name, to paying for trips to vacation destinations for seminars.

"Of the $15.7 billion pharmaceutical companies spent on promotional activities in 2000, $13.2 billion went to promotions directly to physicians, including providing free drug samples, detailing by drug company representatives, and journal advertising," the report, available on the Internet at http://www.kff.org/content/2002/20020321a/, reads.

"This is more than five times the $2.5 billion spent on direct-to-consumer advertising."
Last year, the Kaiser foundation found that the $15.7 billion pharmaceutical industry promotion budget equaled 14 percent of revenues. That compared to 3.7 percent of sales revenues spent on promotion by department stores, 3.9 percent for tobacco products and 10.7 percent for soap and detergent.

The earlier report found drug companies spend only 14 percent of revenues on research and development, although they say drugs are expensive because they cost so much to develop.

Doctors were lukewarm in their praise of the information they get from drug companies on their frequent visits to physician offices or on the free trips.

Fifteen percent said it was "very" useful and 59 percent said the information was "somewhat" useful.