Don’t forget to inquire about herbs when checking for drug interactions
Many providers see increase in herb use
Home care nurses frequently enter homes in which kitchen cupboards or medicine cabinets harbor potentially dangerous over-the-counter treatments that patients forget to mention to their physicians. These medicines have odd names like ginkgo biloba and valerian root, and they can be purchased easily at local health food stores and even supermarkets.
Herbal remedies have grown in popularity over the past decade. They are not government-regulated, which means anyone with a garden patch can grow their own herbs and sell them. The recent surge in the popularity of herbal supplements has caused concern among physicians, home care nurses, and other health care providers because patients may experience dangerous side effects by combining herbal remedies with their prescription medications.
"We found that a lot of patients’ doctors were not even aware that they were using herbs," explains Kathleen Hughes, RN, director of home care for Kershaw County Medical Center Home Health Care in Camden, SC. The hospital-based agency serves rural Kershaw County, which is in the central part of the state.
"We have seen such an increase on medication sheets of people taking herbs," she says. "It’s been phenomenal."
The agency’s nurses record herbs along with prescribed drugs on patients’ medication sheets. But many nurses say they are unfamiliar with the herbal names. "Our concern was how these herbs might be interacting with the patient’s other medication," Hughes says. "And how could we teach patients what’s going on with their medicines?"
The agency plans to have an inservice on herbs and their interactions with prescribed medicines. Hughes has collected some information on various herbal remedies, and when nurses ask her a question about a particular herb, she often calls a local expert, Doug Murray, PharmD, director of pharmacy and clinical services for the 100-bed Kershaw County Medical Center, also in Camden.
Murray also is an adjunct professor at the Univ ersity of South Carolina College of Pharmacy in Columbia, SC. He will be presenting a lecture to pharmacy students on herbal use and Native American medicine.
Olsten Health Services in Virginia Beach, VA, held a staff inservice on herbal remedies after the director of mental health attended a seminar on the topic. "I found that most of the nurses weren’t aware if their patients were on herbal medicines, and what’s scary about that is a lot of patients don’t realize many prescription medications come from herbal sources," says Deanna Lieving, RN, director of mental health for the Olsten agency, which serves a 100-mile radius in eastern Virginia. "So if you take an herbal remedy and a prescription medication at the same time, you could be getting a double dose," she adds.
Lieving discovered at the herbal medicine inservice that about 75% of the staff took some sort of herbal medication. For example, Lieving says she often takes zinc lozenges when she feels as though she is developing a cold or the flu. "You suck on the lozenge, taking 13.3 mg, and continue taking one every two hours until the cold symptoms stop and go away. It really does work, and it works wonderfully with sore throats."
Since her inservice, the agency’s nurses have been asking patients about herbal medications during assessments.
Murray notes an increase in use and interest in herbal medicines. "I see a steady increase in questions from physicians who have patients taking herbs," he says, "and they want to know about interactions with drugs they are taking."
When Murray studied pharmacology in the mid-1970s, there was a course on the study of plants and medicines that come from plants. "But during the time I was in school, they did away with that course in favor of more chemistry and medicinal and clinical avenues." Now herbal treatments are gaining in popularity, and colleges again are beginning to offer courses on the subject, he says.
Murray has educated himself on herbal remedies, their side effects, and how they interact with prescription medications. He suggests home care nurses 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, and it can increase a person’s heart rate slightly, 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, which form a class of agents used to treat heart conditions;
— Ticlid, an anti-platelet drug;
— Coumadin, which is an anticoagulant medication.
"With these drugs, you could have a potentiation of the effects, so it’s something to be careful about," Murray says.
• Garlic
Garlic pills, touted as the great cholesterol reducer on radio and television advertisements, also can 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 impact on increasing 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. But less well-known are its adverse side effects, which include restlessness, insomnia, nausea, and vomiting, he notes. "In the literature, there are three cases of spontaneous bleeding from people taking it, and because of this, some literature is saying you shouldn’t take this with heparin or Coumadin."
Also, people with hemophilia or von Willebrand’s disease, a congenital hemorrhagic diathesis, should avoid ginkgo because of pos sible bleeding. 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. And pregnant women should not take it, he says. "They think people with coronary artery disease, hypertension, or arrhythmia should be cautious in taking it also."
Research shows 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 the amount thought to be effective is not too different from the amount that could cause toxicity, Murray explains. Medical experts also are concerned about people taking Asian ginseng while they are on Coumadin because Coumadin also has a narrow therapeutic window.
• St. John’s wort
This herb also has been widely publicized in recent years. Research shows it helps alleviate depression and anxiety. Its side effects may include restlessness and exhaustion. "They say until more is known or scientifically studied, you probably shouldn’t take St. John’s wort with prescription antidepressants," he says. This is because selective serotonin re-uptake inhibitors like Prozac form a powerful chemical class of antidepressants that is fairly new. "If you take those types of antidepressants, then you should stop three weeks before taking St. John’s wort."
• Valerian root
People may 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. "And if you get it really concentrated, when you make your own teas for example, it can actually decrease your blood pressure a little."
Also, it could cause orthostatic hypotension, which is 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.
Like benzodiazepines, the root has a sedative effect. Therefore, people taking it should be cautious about driving cars.
• Chamomile tea
People sometimes drink chamomile tea to help settle an upset stomach or to relieve tension. But the medical literature warns people who have ragweed allergies to be cautious because they also might be allergic to chamomile.
• Purple cone flower
Also called Echinacea, purple cone flower is used to improve the healing process or boost the immune system. Current medical literature suggests the herb actually does have some properties that might temporarily improve the immune system.
"But some authors are thinking the effect decreases after eight weeks, so it’s better to take it intermittently," Murray says.
In addition to the above herbs, some herbal drugs should be avoided altogether because they are not safe. These herbs might still be found in some stores, or people may find them in the wild, Murray says:
• Blue cohosh
The black cohosh is safe, but the blue cohosh is believed capable of increasing a person’s blood pressure and provoking angina.
• Chaparral
Believed to have blood-cleansing and cancer-fighting properties, chaparral is carcinogenic and toxic.
• Comfrey
This is potentially a hepatotoxin. It damages the liver and is carcinogenic when taken internally. People sometimes use it to promote bone healing, Murray notes.
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