logoThe People's Perspective on Medicine

Herbs and Drugs Interact in Dangerous Ways

Herbs and Drugs Interact in Dangerous Ways

When the former Prime Minister of the tiny island of Fiji was finally released by rebels after two months of captivity, he sat down with his enemies and drank a cup of kava. This traditional Fijian ceremony signified forgiveness.

For centuries, kava has played an important role in many South Pacific societies. They use it in their most important rituals.

But cultures can collide. One man from the island of Tonga was arrested in San Mateo, California, for driving while impaired after a six-hour kava ceremony at his church. He was weaving between lanes although he hadn’t consumed any alcohol.

In North America kava has become a popular anti-stress herb that is used to relax or go to sleep. But some people may not appreciate its pharmacological power or the possibility of dangerous interactions.

In one case, a person intending to switch to kava from the anti-anxiety drug Xanax wound up in a coma-like condition and had to be hospitalized. He made the mistake of combining his prescription pill with the herb.

Scientists are beginning to learn much more about herb-drug interactions. But labels on herbal products rarely reflect up-to-date research.

A report in the Proceedings of the National Academy of Sciences demonstrates that a component of St. John’s wort, hyperforin, has a profound effect on the liver enzymes that process many medicines. It kicks these enzymes into high gear so that the drugs leave the body more quickly and may not be as effective as anticipated.

There are cases in which St. John’s wort seems to have lowered levels of the asthma drug theophylline, the immune-suppressant cyclosporine, the heart medicine digoxin and drugs used to treat HIV and AIDS. Experts anticipate that many other medicines may also be affected, including birth control pills, blood pressure drugs such as Plendil, Sular or Cozaar, the antiseizure medicine Tegretol and the anticancer compound tamoxifen.

Ginkgo biloba is another herb that may pose a risk of interacting with medications. This natural product, which has become popular because of its reputation for protecting the brain, can keep blood platelets from forming a clot. In combination with other anti-clotting medicines such as aspirin or Coumadin (warfarin), ginkgo might increase the risk of dangerous bleeding. A few cases of hemorrhage have been reported.

A number of other dietary supplements might also interact with Coumadin. Feverfew, garlic, ginger and onion may have the potential to increase its anticlotting activity. Coenzyme Q10, ginseng and green tea, on the other hand, might actually reduce its effectiveness.

You may be surprised to discover that some of the dietary supplements and herbs you routinely swallow every morning with your other medications could be creating all sorts of problems.

Anyone who is interested in such interactions may wish to consult our Guides to Herbal Remedies, Ginkgo, Coumadin and St. John’s wort. You can find all our Guides in our People’s Pharmacy Store. Many are free.

You can also go to our free herb library and look up each herb or dietary supplement you are taking. There is an interaction section to help you determine whether you might be taking something incompatible with your “natural” product.

Before combining alternative therapies and standard pharmaceuticals it is prudent to learn if they are compatible. Neither prescription drugs nor dietary supplements provide much information about interactions on their labels.

Rate this article
0- 0 ratings
About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
Get the latest health news right in your inbox

Join our daily email newsletter with breaking health news, prescription drug information, home remedies AND you'll get a copy of our brand new full-length health guide — for FREE!

Screenshots of The People's Pharmacy website on mobile devices of various sizes
Join over 150,000 Subscribers at The People's Pharmacy

We're empowering you to make wise decisions about your own health, by providing you with essential health information about both medical and alternative treatment options.