Check herbal use, interaction with prescriptions
Improve your memory. Enjoy a higher level of energy throughout the day. Sleep better at night. Relieve anxiety.
The promises are attractive. Even better for consumers, the products no longer are hidden in natural food stores. No, these herbal medications and vitamins that improve our lives are on grocery store shelves, so they are easy to pick up along with your bread and milk.
The use of herbal medications and nutritional supplements has risen from 20% of adults in the United States in 19981 to 49% of adults in 2000.2
Many of these people do enjoy the benefits advertised by the manufacturer. Home health nurses, however, need to be diligent about evaluating their patients’ use of herbals, vitamins, and other natural medicines because they can interact with prescription medicines and aggravate some health problems, says Maria R. Toscano, PharmD, consultant with ProMedcare Solutions in Mineola, NY.
"The biggest problem with herbal medication and elderly or ill patients is that many of them thin the blood," Toscano says. Popular herbals such as ginkgo, ginseng, and garlic are blood thinners and cannot be used in conjunction with prescription blood thinners such as warfarin, she says.
The challenge for the home health nurse is that patients and their family members do not always think about telling their physician or nurse about an herbal medication, says Dennis Callahan, RPh, staff pharmacist at St. Mary’s Health Center Pharmacy in Jefferson City, MO. A family member might suggest an herbal medication or vitamin because the patient seems depressed, doesn’t eat well, or has trouble sleeping, he says.
"The home care nurse needs to specifically ask the patient or caregiver about herbals, vitamins, and dietary supplements to make sure potential interactions can be identified," he says. Callahan also recommends that the nurse ask about dietary habits as well, since foods high in certain vitamins also can interact with medications. For example, a patient who likes to eat a lot of spinach is absorbing a lot of vitamin K, which can block the blood-thinning effect of warfarin, he explains.
The most common herbal medications and their potential interactions with medications typically used by home health patients include:
• St. John’s Wort. This popular herbal medi-cation is used as an antidepressant and causes many problems for patients on prescription medications, Toscano says. "It reduces the effect of digoxin by 25%, decreases the effectiveness of anti-rejection drugs used by transplant patients, reduces the effect of drugs used to treat AIDS patients, reduces the efficacy of warfarin, and increases the side effects of any other antidepressant medication the patient may be taking," she explains.
• Ginkgo. Ginkgo is taken to increase blood circulation and to improve memory and mental alertness, but it also acts as a blood thinner, she points out. If the patient also is taking a blood thinner such as warfarin or an aspirin each day, the additional use of ginkgo will exacerbate the medication’s effect and could even cause a brain hemorrhage, Toscano adds. "Ginkgo may also decrease the effect of medications used to control seizures and lower the seizure threshold to the point that the prescription medication does not control seizures."
• Saw Palmetto. Typically used to treat benign prostate enlargement or other urinary inflammations, saw palmetto should not be used by patients undergoing treatment for prostate cancer because it decreases the effect of medications used to treat cancer, she says. Women who are taking estrogen as part of hormone replacement therapy should not use saw palmetto because it increases side effects, including breast tenderness.
• Melatonin. Commonly used to treat insomnia, melatonin can decrease blood pressure so patients already taking blood pressure medication should not use it, Toscano says.
• Soy. Although patients will add soy to their diet without thinking of it as a chemical that can alter prescription medication, it does affect medications designed to control thyroid function, she says. Often added to the diet for the estrogen-like qualities that prevent bone loss and menopause symptoms, a physician needs to know how much soy the patient is ingesting so the thyroid medication dosage can be changed accordingly, she says. Patients who are taking tamoxifen should not take soy since it reduces the effect of tamoxifen, Toscano says. "Iodine levels also need to be monitored since soy contains iodine. If iodine levels become too high, the patient needs to cut back on the amount of soy they take."
• Ginseng. Ginseng is taken to increase physical stamina and mental concentration. Unfortunately for diabetic patients, it also decreases blood sugar, which can lead to hypoglycemia, she says.
• Kava and Valerian. Both kava and valerian are taken to relieve anxiety and aid sleep, as well as a muscle relaxant. "Both herbals increase liver toxicity and should not be used in conjunction with prescription medications such as benzodiazepines and barbiturates, since the combination causes excessive sleepiness and lethargy," Toscano says.
"About 60% of patients don’t tell physicians they are taking additional vitamins, supplements, or herbal medications," she says. "They don’t think it’s important and don’t realize that they can affect other medications," she adds. Vitamin E is a good example, she says. "[More than] 400 IU of vitamin E decreases the effect of warfarin, and [more than] 800 IU can affect the level of good cholesterol."
Because it’s important for home health nurses and physicians to know about everything the patient is taking, education is essential, Callahan says. "People point out that herbals have been used for centuries with no problems in other countries, but I also point out that even today in third-world countries, the people using herbals are not taking them in conjunction with prescription medications, and it’s the combination that causes the interactions," he adds.
Many patients also don’t realize that herbals, vitamins, and dietary supplements are not regulated by the Food and Drug Administration, which means that there are no standards for formulations or quality, Callahan says.
The lack of regulation makes it even more important for home health nurses to stay on top of what patients are taking and what side effects they experience, Toscano says. "This is an ever-changing field, and it requires us to learn new things each week," she says.
"Herbals can be good things," she points out. "There’s nothing wrong with a patient taking them as long as the home health nurse, patient, and physician work together to avoid interactions."
[For more information about the interaction of herbal medications and prescription medications in home health patients, contact:
Maria R. Toscano, PharmD, Consultant, ProMedcare Solutions, P.O. Box 1670, Minneola, NY 11501. Telephone: (517) 742-8386. Web site: www.promedcare.com.
Dennis Callahan, RPh, Staff Pharmacist, St. Mary’s Health Center Pharmacy, 100 St. Mary’s Medical Plaza, Jefferson City, MO 65101. Telephone: (573) 761-7096. Fax: (573) 659-8612. E-mail: [email protected].]
References
1. Eisenberg DM, Davis RB, Ettner SL, et. al. Trends in alternation medicine use in the United States, 1990-1997. JAMA 1998; 280:1,569-1,575.
2. Blumenthal M. Interactions between herbs and conventional drugs: Introductory considerations. HerbalGram 2000; 49:52-63.
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