Herb-drug reaction studies contribute to debate

By Clarisse Douaud

- Last updated on GMT

Related tags: Pharmacology

Two new studies have added weight to arguments in the debate over
whether or not interaction between herbal remedies and prescription
drugs poses a significant threat to the public.

A Canadian study, whose findings were presented at the North American Research Conference on Complementary and Integrative Medicine in Canada last week, found few potential drug-herb interactions in patients with osteoporosis. While a report published in the March issue of Geriatric Nursing found that older women mixing herbal and prescribed medication could be risking their health.

In the first study, 1.3 percent of the 1069 patients assessed were using a contraindicated drug-herb combination.

"In this randomly selected, population-based sample we found a relatively low rate of potential drug-herb interactions, most of which were among subjects using specific cardiovascular medications,"​ the University of Calgary authors concluded.

The second study, at the University of Florida College of Nursing, looked at 58 women over the age of 65 who were taking both herbal and over-the-counter prescription medication. Seventy-four percent of the study's 58 participants were found to have a moderate or high-risk drug interaction.

"Many of these older women do not consider over-the-counter and herbal medications 'real drugs' and therefore don't report them,"​ said the Florida study leader, Dr. Saunjoo Yoon,"However, it is clear that many health-care providers are not following through to learn their patients' complete medication history."

Controversy over drug-herb reactions has come hand-in-hand with the growing popularity of nutraceuticals.

The US retail market for dietary supplements was worth $8.3bn in 2005 - representing a growth of six percent over 2004 - estimates Euromonitor International. What makes critics wary is that such supplements do not require pre-market approval in the US - instead, it is up to companies to report adverse reactions.

The pendulum continues to swing back and forth between those who say the public does not carelessly combine medical and traditional remedies, and those who say they do and that resulting damage is not known.

One of the few points researchers and industry spokespeople seem to agree on is that adverse reactions can be prevented by consulting a doctor - a doctor who is open to herbal medicine that is.

"Cases of herb-drug interactions are extremely rare and, with a little medical supervision, and with more knowledge of complementary and alternative medicine on behalf of more physicians and pharmacists, easily avoided,"​ National Nutritional Foods Association president Daniel Fabricant told NutraIngredients-USA.com.

Fabricant also hinted that the energy and fuss surrounding the drug-herb debate might be better redirected towards the issue of mixed prescription medications.

"The safety of botanical dietary supplements, based on the evidence, must be considered much more favorably than that of prescription medications (drug-drug interactions), so the risk should be attributed appropriately."

Related topics: Research

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