The medical world has been rocked in recent years by the widespread use of alternative therapies in treating illnesses and injuries. In fact, it’s now estimated that as many as one in three adults in the U.S. uses herbal remedies and other alternative therapies. Sales of herbal medicine skyrocketed nearly 60 percent in 1997, amounting to an incredible $3.24 billion.

Yet, doctors are not always aware of the fact that their patients are using alternative treatments. One study a few years ago indicated that only 58 percent of the physicians surveyed always or often question their patients about alternative therapies.

A majority of doctors questioned believe that herbal remedies have no side effects or quite limited side effects. As a result of this study, researchers determined that physicians tend to underestimate how many of their patients are using alternative therapies.

The Safety Issue

Although alternative therapies are more popular than ever, it still isn’t clear how safe these remedies are. Consequently, it can be hard for a pharmacist to advise a patient about the proper use of such therapies in connection with prescription medication.

Given the widespread use of alternative therapies, it stands to reason that there would be concerns about whether herbs are safe to use in conjunction with prescription drugs. The concern among doctors is particularly high when it comes to warfarin.

A Closer Look at Warfarin

Warfarin also goes by names such as Coumadin, Jantoven, Marevan, and Waran. For the most part, it is taken orally, although it can be injected as well. The drug is a synthetic derivative of coumarin, which is found in a number of plants. Interestingly enough, warfarin was first used as a rat poison, but it is no longer used that way.

Warfarin is a medication which prevents the development of blood clots or prevents them from enlarging. Doctors frequently prescribe it for patients who experience an irregular heartbeat following a heart attack or heart surgery.

The medication is usually taken once each day, and must be used exactly as directed. At times, it may be used in conjunction with other drugs in the treatment of lung cancer.

However, for the most part, other medications should not be taken with warfarin because they may interfere with the effectiveness of the drug. One of the most famous early users of warfarin was U.S. President Dwight D. Eisenhower, who used it as a remedy for his heart trouble.

Doctors and pharmacists say that patients using warfarin should not start consuming herbal products without consulting a physician first. It may be particularly harmful to mix warfarin with bromelains, coenzyme Q10, danshen, dong quai, garlic, Ginkgo biloba, and St. John’s wort. Even foods containing vitamin K, such as broccoli and cauliflower, may interfere with successful warfarin use.

Side effects associated with warfarin include stomach upset, diarrhea, fever, and headache. At times, the effects may be more severe and may include blood in the urine and chills. Any serious side effect should be reported to federal health officials, who monitor adverse reactions to warfarin.

Because warfarin use can be accompanied by heavy bleeding, patients are advised to undergo regular blood testing—as often as twice a week. That way, doctors can monitor the degree of anticoagulation associated with its use.

Warfarin/Herbal Interactions

In their article, “Potential Interactions Between Alternative Therapies and Warfarin," researchers A.M. Heck, B.A. DeWitt, and A.L. Lukes examined warfarin in greater depth. The research team noted that the issue of alternative therapy use is especially important with respect to medications such as warfarin which have small therapeutic indexes.

For instance, the researchers found that there are a number of herbal products that can increase bleeding when combined with warfarin. In fact, the bleeding can be so pronounced that it a patient can hemorrhage. These include anise, chamomile, fenugreek, ginkgo, licorice root, tumeric, and willow bark.

In addition, ginseng, green tea, and vitamin E may lead to some unpleasant side effects when combined with warfarin. In fact, it appears that warfarin is the drug most likely to be associated with adverse physical reactions when combined with herbal treatments.

The Difficulty of Interpreting Data

Yet, it should be noted that it is difficult to interpret data about interactions between herbs and warfarin. This is because the evidence tends to be based on animal studies or individual cases rather than large-scale human studies. As a result, physicians say that additional research is needed in order to explore the range of possible effects from herbal supplement/warfarin interactions.

The U.S. Food and Drug Administration asks pharmacists to report any known cases of interaction between medication and alternative therapies to federal health authorities. The more data collected, the easier it will be to determine whether there is a conflict between the two forms of treatment.

Some Additional Considerations

Doctors acknowledge that there are comparatively few adverse reactions linked to herbal products. In other words, it is far more likely that a patient will report a problem with a prescription drug than an herbal remedy. The reasons for this are not entirely clear.

Pharmacists say it may not be that herbal remedies are inherently safer than prescription drugs. Rather, it may simply be that consumers are less likely to report side-effects stemming from herbal therapies.

As a result, it is important that pharmacists take a proactive approach, questioning prescription drug users about their use of herbal remedies. In this way, a clearer picture may emerge about the impact herbs may have on the effectiveness of warfarin and other prescription medications.

The Bottom Line for Warfarin Users

Warfarin has become a popular form of medication, meaning that it is fairly routinely described. Similarly, people have become accustomed to using herbal remedies for a wide variety of ailments, from digestive problems to depression.

Yet, given the available medical evidence, caution should be used when a patient using warfarin is considering using herbal therapies. In a number of cases, the possible negative side-effects may outweigh the potential benefits.