No Minor Mix-Up
When it came to taking herbs and vitamins, retired engineer Richard Sommers would try a handful of this and several capsules of that and sometimes feel a little better. But he began to think there was a better way.
He consulted a doctor trained in alternative medicine to see if he was doing himself any harm by combining megadoses of such dietary supplements with powerful prescription drugs for his heart and thyroid problems.
The internist immediately spotted problems in Sommers’ regimen. The ginkgo biloba and the garlic pills that Sommers downed daily both inhibit blood clotting--a potential problem since he also was on a prescription blood-thinner.
The 71-year-old Beverly Hills resident was advised to give up ginkgo, relegate garlic “to food, not supplements,” and reduce daily doses of vitamins C and E.
Sommers, who now is “feeling much, much better,” is among the growing number of Americans drawn to the natural benefits of herbal remedies and dietary supplements usually without knowing what effect the products might have on their medications.
In 1998, dietary supplements constituted a $13.9-billion segment of the $25.8-billion U.S. nutrition industry, according to Nutrition Business Journal in San Diego.
A national telephone survey of 2,000 adults conducted in the spring by Princeton associates for Prevention magazine found that 49% of those interviewed reported using an herbal remedy in the past 12 months, and 24% reported regular use.
Dietary supplements have become readily available in grocery, drug and health-food stores, but information about potential interactions isn’t easy to come by for most consumers.
Few doctors have special training in herbal medicine, and the federal government has no central database to which doctors or their patients can turn for guidance--only some “adverse event” reports voluntarily filed by doctors and health officials with the Food and Drug Administration, available at https://www.fda.gov/medwatch.
Little Controlled Research Has Been Done
Nor has there been much controlled research to alert doctors, pharmacists and consumers to any interactions involving the growing array of natural remedies. And other resources, such as Web sites and herbal guidebooks, warn mostly of theoretical interactions, such as the result of mixing licorice root with the heart drug Lanoxin (the body could be drained of important potassium).
Furthermore, although prescription-drug packages warn against some possible interactions, supplement manufacturers aren’t required to list potential interactions on their labels because supplements are regulated as foods, not drugs, under 1994 federal legislation.
“It’s not always easy to find this information,” said Paul M. Coates, director of the Office of Dietary Supplements at the National Institutes of Health in Bethesda, Md. “It’s a little easier in the kind of environment in which these things are regulated.”
In Germany, where dietary supplements are strictly regulated--and sold only by prescription--”there is a history of reporting adverse events that could allow for uncovering this kind of interaction,” Coates said. For example, German researchers found that taking the herbal antidepressant St. John’s wort with a blood-thinner lowers levels of the blood-thinner in the body, making the prescription drug less effective than it should be.
In addition, Coates said, “it’s common for physicians in German-speaking countries to receive education and training in herbal remedies. It’s not common here, so physicians here are generally not as knowledgeable about what their patients are taking and what they would do with the information if they had it.”
Doctor-patient relationships can be key to identifying potentially troublesome combinations.
But only a few doctors--often anesthesiologists preparing a patient for surgery--inquire about supplements when asking about prescription and over-the-counter medications. Sometimes, patients may feel uncomfortable discussing their use of natural preparations for fear of a negative reaction.
“A lot of patients have this whole secret world of vitamins and supplements, and if they were to mention that to their doctors, they would get one of those disapproving looks,” said pharmacologist Joe Graedon, who with his wife, Teresa, a medical anthropologist, writes about herbs and herb interactions.
Few Disclose Use of Remedies
Frequently, however, patients don’t mention supplements because they don’t consider them drugs.
“The problem is there’s a lay belief that if it’s natural it’s harmless, and that’s not completely accurate,” said Dr. Mary Hardy, director of a program at Cedars-Sinai Medical Center that combines traditional and alternative medicine.
Cedars pharmacist Marilyn Friedberg also has found that most patients don’t disclose the supplements they use unless she asks. “My feeling is patients continue to see alternative supplementation as nonmedicinal. Anything sold over-the-counter has a ‘safer’ feeling to the general public than anything sold as prescription-only.”
In a landmark study that appeared in the Jan. 28, 1993, issue of the New England Journal of Medicine, Dr. David Eisenberg of Harvard University found that one-third of patients surveyed were using alternative medicine and 72% of them didn’t tell their doctors. A follow-up study that appeared in the November 1998 Journal of the American Medical Assn. found that 42% of those surveyed used nontraditional medicine, and about 40% of them still weren’t disclosing it.
Little by little, however, anecdotes and warnings about potential interactions are coming to light through Internet sites, professional journals and literature being distributed to pharmacists. The Graedons are most concerned about combining substances, such as ginkgo and aspirin, that thin the blood or prevent clotting.
They also warn against combining St. John’s wort with prescription antidepressants from the category that includes Prozac and Zoloft. Such stacking could cause serotonin syndrome, an excess of the brain chemical, which produces tremors, headache and, in some cases, comas.
“The point here is that you’ve got people who are depressed, who are taking antidepressant medications like Zoloft who decide for reasons like ‘I want a more natural way’ that they’ll add St. John’s wort and fade off their Zoloft. In the meantime, they end up in the hospital because of this added effect,” Joe Graedon said.
St. John’s wort poses another potential problem in combination with the heart drug digoxin. A German study in the October issue of the journal Clinical Pharmacology and Therapeutics found that, if the two are taken together, the dose of digoxin became less effective.
Like other supplements in the United States, St. John’s wort falls into the category of food supplement under the Dietary Supplement Health and Education Act of 1994. That law prohibits supplement manufacturers from making any claims to cure or treat specific conditions or diseases.
“Supplements are not meant to be used as a treatment or a cure,” said Corinne Russell, a spokeswoman for the Consumer Healthcare Products Assn. in Washington, which represents makers of supplements and over-the-counter preparations. “They’re intended as a supplement to the diet for overall wellness.”
Products Assumed Safe Unless Proved Otherwise
Russell contends that “interactions between prescription drugs and dietary supplements are very rare” and cited knowledge of only one published case about interactions between the blood-thinner Coumadin and ginkgo.
Still, much research remains to be done. Coates’ office, created under the 1994 legislation, is charged with supporting research and educating the public about the benefits of dietary supplements.
“The issue of interactions between herbs and drugs is one that needs further research, and the fruits of that research need to become available for the public,” Coates said.
Coates noted that under the 1994 legislation, the products are assumed to be generally safe unless proved otherwise. That means they hit the market first and it’s then up to FDA to evaluate any potential adverse effects or interactions.
Another obstacle to learning more is that supplement makers have little incentive to pour money into research. Many of the compounds have been around for years, if not centuries, so further studies would not produce patents and would not bring in extra money for the manufacturers.
The NIH has funded two botanical research centers, at the University of Illinois and UCLA, where center director Dr. David Heber said he hopes a library offering scientific information on herbal supplements will become a resource for doctors nationwide.
The NIH might one day work with such an institution to compile a good national database for interactions, Coates said.
For now, consumers are advised to do their own research using available resources and to rely on the increasing expertise of pharmacists.
Although label information can be skimpy, some manufacturers do provide interaction cautions in other formats.
Nature Made supplements, produced by Pharmavite Corp. in Mission Hills, includes information about interactions on its Internet site, said Paul Bolar, vice president of regulatory and legal affairs. The company also has developed materials for pharmacists and manages a toll-free service in which operators can answer questions about drug interactions.
“A lot of this information is probably in the developmental stage because products are relatively new to the mass market,” he said. “So there’s probably a lot of sifting of anecdotal information that will have to take place before we come up with the definitive answers on what herb-and-drug interactions occur.”
The Consumer Healthcare Products Assn. is working on a brochure to teach consumers about interactions with prescription drugs.
In the meantime, Hardy would like to see manufacturers include more information on the package.
“We’re never going to put the genie back in the bottle, so we might as well make the label on the bottle make sense,” she said. “The FDA is never going to get these products completely off the market; public opinion is too strong. So let’s have a rational discussion about what information consumers need and health providers need and let’s give them that.”
