Herbs may have harmful interactions with prescription drugs

By Laurie Wade

Nevada Herald

Every month, Nevada Regional Medical Center hosts a "Lunch and Learn" with presentations on various medical topics. This month's topic was "Herbs and Medications" presented by Dr. Robin L. Miller, Pharm. D.

"Herbs have been used for thousands of years to help maintain good health." Miller said.

Today, they are still commonly used, both as alternatives to modern medicine and in conjunction with other treatments.

Herbs may claim to help specific diseases and to aid certain body processes and functions, Miller said, but people should be careful in taking herbal remedies.

Herbs are considered dietary supplements. The Food and Drug Administration regulates the amount of medication in drugs, therefore dietary supplements are not standardized under the same strict rules as medications

All dietary supplements, however, must carry a "supplement facts" label. This label must include the names of the ingredients listed by common name, total quantity of all dietary ingredients, the words "dietary supplement" as part of the product name, and the part of the plant from which the ingredient is derived.

Labels must also contain the appropriate serving size, directions for use, quantity, and the name and place of business of the manufacturer.

Herbal products are made from different parts of the plant. The part of the plant used is a key to the herb's potency as is the time harvested, the climate grown in and the weather experienced by the growing plant.

Special attention needs to be paid to medications and the ingredients in all herbs because herbs may interact with medications making either the herbal product or the prescription medicine less effective, Miller said.

For example, if St. John's Wort is taken along with prescription medications for depression, it might increase the production of serotonin and cause serious side effects including heart problems, shivering, and anxiety. Taking St. John's Wort with medications that are processed by the liver might decrease the effectiveness of the medication by increasing how quickly the liver breaks down certain medicines.

Green tea is another good example. According to information from the Natural Database, a resource Miller used to supplement her presentation, it contains antioxidants and other substances that might help protect the heart and blood vessels, but when mixed with some medications like certain antibiotics, the level at which the body breaks down caffeine decreases, leading to jitteriness, headache, fast heart rate, and high blood pressure.

Some herbal supplements can and do interact with surgery and anesthesia medications.

They can prolong the effects of anesthesia, increase the risk of bleeding, elevate blood pressure and increase heart rate. Some herbal supplements can also inactivate medications for pain or prevent blood clotting and lower blood sugar, causing hypoglycemia during surgery and recovery.

"Always tell your surgeon and anesthesiologist about any dietary supplements that you may be taking, because you don't want them to interact badly with the medications they give you." Miller said. "You also need to discontinue use of all dietary supplements two to three weeks before elective surgery so it all gets out of your system to keep it from interacting badly."

Finally, Miller said, those who have any questions about medicine or dietary supplements, should be sure to ask a pharmacist or doctor, especially if prescription drugs are already being used.