Side Effects from Supplements
Many cancer patients are using complementary and alternative therapies without telling their doctors-and the consequences can be dangerous.
At the recent American Medical Association writer's conference in San Francisco, Dr. Jonathan Moss of the University of Chicago warned that certain herbal supplements can risk serious complications during surgery and anesthesia. He specifically cited ginko biloba, echinacea, kava, St. John's wort, valerian, ephedra, garlic and ginseng.
Moss noted that some of these supplements can interact with common analgesics and dangerously intensify their effects. Others have blood-thinning properties and can reduce the blood's ability to clot.
This makes it critical, Moss warned, for patients to advise their doctors of any herbal supplements they are taking-and for doctors to ask their patients about supplement use. Yet this occurs in an alarmingly low percentage of cases.
"Herbs have important biological properties that are generally safe, but during surgery and recovery they can be problematic," he said. "Herbs are drugs and they need to be treated as such."
In a study published in the Journal of Clinical Oncology, researchers from the University of Texas found that 99.3 percent of outpatient cancer patients at the school's M.D. Anderson Cancer Center had heard of complementary and alternative medicine, and 83.3 percent had tried at least one approach.
However, about 60 percent of these patients said they did not discuss complementary and alternative therapies with their doctor, although when interviewed in more detail about individual therapies, this rate dropped to a lower-but still significant-38.2 percent.
In a presentation at a recent meeting of the American Society for Clinical Oncology in New Orleans, Dr. James Metz of the University of Pennsylvania Cancer Center found that cancer patients who use unconventional medical treatments only tell their doctor when specifically prompted to do so.
Of the 196 cancer patients interviewed in the study, only 13 percent revealed their use of unconventional medicines-defined as those not proven in the eyes of the medical profession-when asked about over-the-counter and prescription drugs. But when given specific questions about the use of vitamins, herbal supplements, shark cartilage and therapies such as guided imagery music or medication, a total of 92 percent admitted they did.
This situation is made worse because many doctors are surprisingly unaware of the use of complementary and alternative treatments by their patients. In one study of prostate cancer patients by Dr. Gary Kao of the Hospital of the University of Pennsylvania and Pamela Devine of the Department of Veterans Affairs Medical Center in Philadelphia, 37 percent of the patients were found to be using at least one complementary health practice. However, the physicians estimated that only 4 percent of their patients used such therapies.
Writing in the journal Cancer, Kao and Devine said that the danger of such a wide communication gap is that many patients are making their own conclusions regarding how the complementary treatment would interact with conventional medicines in the absence of specific instructions by their healthcare provider.
In a symposium on complementary and alternative medicines (CAMs) at the American Society for Parenteral and Enteral Nutrition's 25th Clinical Congress in Chicago, speaker after speaker warned that the number of known nutrient-to-nutrient and nutrient-to-drug interactions is growing "exponentially." The culprit: The exploding number of herbs and dietary supplements being used by patients, usually without their doctor's knowledge or consent.
The panelists cautioned that even seemingly safe herbs and supplements could be dangerous when taken in excessive doses, or when mixed with other therapies, or especially if taken by patients with certain diseases. Furthermore, these therapies can sometimes mask patient symptoms or skew laboratory tests, thus affecting decisions about traditional medical treatments that might unnecessarily be abandoned.
And the situation will not get better any time soon, they warned, because there are no major definitive clinical trials evaluating many of these compounds. This is further complicated by the fact that many physicians themselves are not knowledgeable about the complementary and alternative therapies their patients may be taking.
SOURCES:
American Medical Association writer's conference, San Francisco, California, October 28, 2001
Journal of Clinical Oncology, July 2000; 18:2505-2521
Abstracts from the Annual Meeting of the American Society of Clinical Oncology, May 23, 2000, New Orleans, LA
American Society for Parental and Enteral Nutrition's 25th Clinical Congress, January 23, 2001, Chicago, Illinois