Dietary supplements could interact with heart medicines and increase the risk of adverse reactions, according to the results of a new study from the University of Michigan.
Nearly three-quarters of heart patients surveyed in the study used some kind of alternative medicine approach to help them heal, but the dietary supplements chosen by one-third of them were found to have a potential risk when combined with other treatments.
The findings, presented at the American College of Cardiology's 51st Annual Scientific Session earlier this week, were of such concern to researchers that they have launched a larger study of the issue.
"Heart patients seem to be turning to alternative therapies even more than the general population, even while they stick to mainstream drugs too," said Eva Kline-Rogers who coordinated the study. "But they may not know that some of these substances could pose a hazard when taken with certain heart medications, and if they don't tell their doctors, the risk may go undetected. We need to encourage patients to be cautious, learn the risks, and share information with their health care providers."
The study involved 145 patients who had been hospitalised for heart attack or angina within six months before being surveyed by phone last year.
The study started after cardiologists at the University of Michigan noticed that some patients came to their appointments with lists of all the prescription drugs, over-the-counter medicines, vitamins, minerals and food supplements that they were taking - wondering which they could cut out to save money or reduce hassle.
The physicians would explain that the prescription medications had years of research evidence behind them to show that they worked, while many alternative treatments, even vitamins, had little or no scientific proof to back them up, and could cause side effects.
So, the researchers set out to see how many of their patients were using different diet, physical or body-mind techniques, what it was costing them, and whether they told their doctors about it.
They knew that previous studies by other teams had shown that nearly half of all Americans use alternative techniques - everything from multivitamins to 'energy healing' - and that patients could face a risk of bleeding problems, including gastrointestinal bleeding or surgical complications, if they take certain mainstream medications along with certain alternative substances.
Many heart patients have a prescription to take aspirin, Coumadin (warfarin) or Plavix (clopidogrel) to thin their blood, prevent clotting and reduce their risk of heart attack, stroke or other problems. But dietary supplements like gingko biloba, ginseng, garlic, vitamin E, fish oil or coenzyme Q10 can also cause blood-thinning (anticoagulant) effects, and doses aren't carefully studied and controlled like those for medicines, the researchers said. The total anti-clotting effect from taking both at once, or other interactions between drugs and supplements, are what worry experts.
Sixty per cent of the surveyed patients used supplements, vitamins or herbs, while 43 per cent used mind-body or body techniques to help combat their heart problems, while many patients used both, Kline-Rogers said.
Among all the patients who used complementary and alternative medicine (CAM) techniques, 31.8 per cent used at least one blood-thinning prescription medication and one diet supplement that could reduce clotting. This particular statistic troubled Kline-Rogers and her colleagues most. In the broader study they are currently conducting, they are asking heart patients about their use of prescription medications and CAM techniques, their intake of beverages such as green tea and red wine that can also interfere with clotting, and their incidence of minor bleeding symptoms.
The vast majority - 75 per cent - of people who chose food supplements, vitamins or herbs told their doctor what they were taking. The rest said they didn't think it was necessary, or didn't care to discuss it, or that their doctor didn't ask. Kline-Rogers and her colleagues were pleased by the high percentage of those who told their doctors. But they noted that both clinicians and patients need more education about the importance of talking to one another about CAM use, due to the potential risks of bad interactions between CAM techniques and conventional ones.