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Some cause potentially dangerous interactions
If chronically ill patients become disenchanted with Western medicine, they often turn to alternative therapies, including herbal remedies and supplements.
"When Western medicine doesn’t offer patients an acceptable solution, many start looking for anything that will help them," says Doug Murray, PharmD, director of pharmacy and clinical services at Kershaw County Medical Center in Camden, SC, and an adjunct professor at the University of South Carolina College of Pharmacy in Columbia.
Murray says he also has seen an increase in use of and interest in herbal medicines.
"I see a steady increase in questions from physicians who have patients taking herbs," he says. "They want to know about possible interactions with drugs their patients are taking."
The real risk lies in patients who don’t inform their physicians about their herb use, Murray notes.
"Many patients are reluctant to talk to their physicians and care providers about taking herbs. They often feel as if they are doing something their health care providers might not approve of," he says. "Patients have this guilt about herb use. They also often don’t feel that herbs are medicine. They think of herb use as something natural that they are doing for their health."
Congress paved the way to ensure herbal supplements don’t have to go through the expensive and rigorous drug-testing process in the United States through passage of the Dietary Supplement and Health Information Act in 1994. When concerned consumer advocates, pharmaceutical representatives, nutritional supplement manufacturers, and health care professionals debated whether herbs were drugs or dietary supplements, the non-drug advocates won. As a result, herbs are not government regulated, meaning anyone with a garden can grow their own herbs and sell them.
A worst-case scenario occurred in 1989 when an outbreak of eosinophilia-myalgia syndrome (EMS) in the United States was associated with the use of L-tryptophan, an over-the-counter dietary supplement used for weight loss. There were more than 1,500 cases of EMS, including 38 deaths, reported to the Atlanta-based Centers for Disease Control and Prevention, according to the U.S. Food and Drug Administration (FDA) in Washington, DC. Some people with EMS experience severe pain and bleeding.
More than 95% of these cases were traced to L-tryptophan supplied by Showa Denka K.K. of Japan. Researchers found some trace-level impurities, suggesting that a contaminated batch contributed to the outbreak. The FDA limited the availability of L-tryptophan supplements, including enforcing an import alert, because of the outbreak.
While this type of danger rarely occurs with food supplements and herbal remedies, health care professionals still advise people to avoid purchasing these products from unfamiliar manufacturers. Recently, several major drug manufacturers started producing herbal remedies, so consumers now have choices that include manufacturers with a proven track record, Murray adds.
Providers should urge patients to look for the word "standardized" on the label of their herbal supplements, says Cyndi Thompson, PhD, RD, clinical nutrition research specialist at the University of Arizona at Tucson. "Basically, that term means that the product has gone through some analysis to determine its activity."
"One very real problem with supplements that providers should make clear to their patients is that with supplements, what is on the label isn’t what’s actually in the bottle," Thompson notes. "At least with standardized products, patients are more likely to get what they think they are paying for."
Herbal supplements are even finding their way into the food supply. Recently several natural food companies have introduced such products as tortilla chips with St. John’s Wort and dried ginseng rings.
This surge in the popularity of herbal supplements has caused concern among providers, because patients may experience dangerous side effects by combining herbs with their prescription medications.
"We found that a lot of patients’ doctors were not even aware that their patients were using herbs," says Kathleen Hughes, RN, director of home care for Kershaw County Medical Center Home Health Care in Camden, SC. "We have seen such an increase on medication sheets of people taking herbs."
Hughes explains that the agency’s nurses record herbs along with prescribed drugs on patients’ medication sheets.
"Our concern was how these herbs might be interacting with the patient’s other medication," she says. "How could we teach patients what’s going on with their medicines?"
"If providers take a hard line or defensive approach when discussing different supplements, their patients are going to simply clam up and not share information about the supplements they may be taking," adds Thompson. "That could result in a very detrimental situation. Providers must listen to their patients and provide them with logical information regarding supplement use."
Murray says his hospital now formally asks every patient on admission for a complete medication history, which includes vitamins, over-the-counter and herbal products.
He says it’s important for all providers to do the same, but also consider the possibility of herbal supplements when patients report new or unexpected changes in their health status.
"There are some developments that should tip you off, or at least cause you to question the possibility of herbal use," he notes. "For example, if a patient is doing well for several months on blood pressure medication and then suddenly, their medication no longer controls their hypertension. You have to start asking questions. It’s like being a detective." (For more recommendations on the management of your patient’s use of herbal supplements, see boxes on pp. 66 and 67.)
Of course, in addition to possible herbal use, there is the possibility that the patient has stopped taking an old prescription or started a new one, he says. Questions he suggests providers ask their patients include:
• Have you stopped taking any medications or added any new medications since you experienced these symptoms?
• Have you started taking any new vitamins or herbal supplements, or stopped taking any vitamins or herbal supplements since you have experienced these symptoms?
• Have you recently tried a new over-the-counter medication?
Providers should always ask their patients why they are taking herbal supplements, adds Thompson.
"They may be experiencing a problem that you can suggest other solutions for," Thompson notes. In addition, she suggests providers get good answers to questions about how much of the supplement patients are taking.
American medical journals are taking notice of the trend, Murray notes. The Archives of Internal Medicine had a review article on herbs as medicine in its Nov. 9, 1998, issue, and American Health Consultants, publisher of Disease State Management, publishes entire newsletters (including Alternative Medicine Alert and Alternative Therapies in Women’s Health), devoted to herbs and other alternative remedies. Articles on herbal supplements have also appeared in recent issues of such reliable, peer-reviewed journals as the American Journal of Health Services Pharmacy.
"Look for information in peer-reviewed scientific journals. More information is coming out, and I find most of the information I use in current journals," says Murray, who has prepared lectures for pharmacy students on herbal remedies.
A great deal of research is available on herbal remedies. For years in Germany, herbs have been prescribed by physicians and covered by insurance companies.
"The Germans are the backbones of this," Murray notes. "They’ve done the research and it’s been published. The Germans also have a lot of standard review textbooks that are accepted now in the United States."
Murray has educated himself on herbal remedies, their side effects, and how they interact with prescription medications. He suggests providers learn about these basic herbal remedies and how they might adversely affect patients’ health:
• Feverfew: This herb is used for prophylactic treatment of migraine headaches. Pregnant women should avoid it. It also can slightly increase a person’s heart rate, Murray says. Because of this potential side effect, medical experts now think people should avoid using feverfew if they are taking any of these medications: calcium channel blockers; ticlid, an anti-platelet drug, or Coumadin.
"With these drugs, you could have a potentiation of the effects, so it’s something to be careful about," Murray says.
• Garlic: Garlic pills, pushed as the great cholesterol reducer on radio and television advertisements, can also decrease blood pressure, as well as cholesterol. "There are some warnings that people who take anticoagulants like Coumadin while taking garlic may increase their chance of bleeding," Murray says.
• Ginkgo biloba: This herb has received a lot of news coverage recently about its ability to increase circulation to the brain and extremities. Some researchers claim it might be a good antioxidant, and they’re studying it for use with Alzheimer’s disease patients as a way to improve short-term memory. It’s also thought to help with ringing in the ears. Less well known are its adverse side effects, which include restlessness, insomnia, nausea, and vomiting, Murray notes.
"In the literature, there are three cases of spontaneous bleeding from people taking it. Because of this, some literature is saying you shouldn’t take this with heparin or Coumadin."
In addition, people who have hemophilia or von Willebrand’s disease, should avoid gingko because of the bleeding potential. Experts also warn people on nitrate drugs and antidepressants to avoid the herb.
• Asian ginseng: "Asian ginseng is a real popular drug that is thought to increase energy, improve mood, and improve resistance to infection," Murray says. "It’s the top-selling herb in the U.S., with $78 million in sales annually."
The herb has been studied for use by postmenopausal women and Alzheimer’s disease patients. There are some potential adverse side effects, such as insomnia, nervousness, and irritability. Pregnant women should avoid this herb, he says. "They think people with coronary artery disease, hypertension, or arrhythmia should be cautious in taking it, also."
Research shows that Asian ginseng might interact with digoxin and increase the levels of digoxin in the blood. This could be a serious problem, because digoxin is a dangerous drug that has a narrow therapeutic window, meaning that the amount thought to be effective isn’t far from the amount that is toxic, Murray explains.
Medical experts also are concerned about people taking this herb while they are on Coumadin because it also has a narrow therapeutic window.
• St. John’s Wort: This herb has also been widely publicized in recent years. Research shows it helps alleviate depression and anxiety. Its side effects may include restlessness and fatigue.
"They say until more is known, you probably shouldn’t take St. John’s Wort with prescription antidepressants," Murray says. This is because selective serotonin re-uptake inhibitors (SSRIs) like Prozac are a powerful chemical class of antidepressants that are fairly new.
Practitioners should conclude antidepressant therapy at least three weeks before patients begin taking St. John’s Wort, he adds.
• Valerian root: People often take this herb as a sleep aid for nervous disorders. Although it appears to be safe as far as adverse side effects are concerned, medical experts advise people to take it for only one week at a time, Murray says. "If you get it really concentrated, when you make your own teas for example, it can actually decrease your blood pressure a little."
It also could cause orthostatic hypotension, the dizziness that occurs when a person who is sitting or lying down stands up quickly and loses his or her balance. For this reason, people who are taking blood pressure medications should take precautions when using valerian root.
The herb also acts in a similar way to benzodiazepines in that it has a sedative effect. For this reason, people taking the herb should be cautious about driving cars.
• Chamomile tea: People sometimes take chamomile tea to help settle an upset stomach or to relieve tension. The medical literature warns people who have ragweed allergies to be cautious because they might also have an allergy to chamomile.
• Purple cone flower: Also called Echinacea, the herb is used to improve the healing process or boost the immune system. Current medical literature suggests the herb actually does have some properties which might temporarily improve an individual’s immune system.
"Some authors are thinking the effect decreases after eight weeks, so it’s better to take it intermittently," Murray says. (For a list of herbs you should caution your patients to steer clear of completely, see article on p. 69.)
For more information on herb-prescription interactions, see: Miller LG. Herbal medicinals: Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998; 158:2,200-2,211.