Adverse reactions to herbal medicine, drugs often unreported: Study
Last Updated: Monday, July 23, 2007 | 9:16 AM ET
The Canadian Press

Mixing herbal medicines and prescriptions could pose undiscovered health
risks because many negative reactions aren't being reported or tracked, a
new study suggests. The adverse effects of taking prescription drugs with
natural health products are dramatically under-reported or not reported at
all, so their potential risks may be underestimated by health-care
professionals and the public, the study found.

"People look at risks based on what's known. If it's not being reported, it
can't be known," said Dr. Sunita Vohra, an associate professor of pediatrics
at the University of Alberta and the study's lead author. 'Treat products
with respect - if they can help you, they can potentially harm you."

The study found almost half the 132 pharmacists surveyed had seen a
potential adverse reaction in patients who mixed prescription drugs and
natural products, but only two of them reported the incidents to Health
Canada. By contrast, 19 per cent of pharmacists said they had reported
adverse events from mixing prescription and non-prescription drugs. The
finding startled the study's co-authors - researchers from University of
Alberta, the University of Toronto and Health Canada. "We didn't anticipate
the number of potential natural health product-drug interactions that
community pharmacists were seeing, nor did we anticipate their reporting
levels," said Vohra.

Researchers suggest the health-care system needs a better method of tracking
the incidents encountered by consumers using both prescription and herbal
medicines. (CBC) Adverse events ranged from mild rashes and headaches to
more serious consequences for some patients. Those on prescribed blood
thinners, for example, can put their health at risk if they take natural
products that they may not realize also act as blood thinners. Vohra said a
large proportion of the Canadians who use natural products also use
prescription medication, and the health-care system needs a better method of
tracking the incidents encountered by consumers using both products.

"We're not saying natural health products aren't safe," said Vohra. "We're
not saying they are safe, or that you can't ever use them with drugs, or
that you must use them with drugs. There's no way we have enough information
to make those sorts of absolute statements." Consumers need to handle
natural health products with caution, Vohra said. "Treat products with
respect - if they can help you, they can potentially harm you," Heather
Boon, a University of Toronto pharmacy professor, said she finds it
troubling that pharmacists aren't reporting adverse events, although she
knows from personal experience that they are busy and often don't have time
for added paperwork. Boon said a followup study is underway looking at the
under-reporting. Vohra noted consumers can also file reports on adverse
reactions to Health Canada.