Don't give kids on drug-thinner natural products: docs

TORONTO - Giving herbs, vitamins and other natural health products to children taking the blood-thinning drug warfarin for congenital heart defects could increase their risk of clots and bleeding, the Canadian Cardiovascular Congress was told Monday.

"We just assume these products are safe because they are `natural' and don't require a prescription," said Dr. Patti Massicotte, director of the pediatric thrombosis program at Stollery Children's Hospital in Edmonton.

"The problem is that the anticoagulant action of warfarin is unpredictable on its own, so adding dietary supplements to that can be a challenge," Massicotte said in a release. "Sometimes that product is the straw that breaks the camel's back and could push children into high-risk situations."

While many supplements can cause changes in the blood and shouldn't be taken with the blood-thinner, she said there is little research on drug interactions with these types of products.

In a study of children taking warfarin, Massicotte and nurse practitioner Mary Bauman found that 37 per cent were taking some kind of dietary supplement and 22 per cent of their parents and 10 per cent of their healthy siblings were taking them as well.

Yet few parents informed their doctors about their children's use of natural health products, the researchers said.

"It is interesting that only 10 per cent of siblings were taking these products," said Bauman, founder of the pediatric outpatient anticoagulation clinic in Edmonton. "Parents more commonly gave these products to their child with health challenges, believing that these products are safe and may provide benefit."

Some of the most common natural health products taken by the children in the study included chamomile, lemon, fennel and green tea. Multivitamins and minerals were also high on the list, but they can cause problems if they contain vitamin K, which enhances clotting and could make warfarin less effective.

"I think that the really important thing is for health-care professionals to ask families whether or not they are taking natural health products and for what purposes," Bauman said.