Mixing medicine with herbal supplements could be deadly

A new warning goes out to people who use herbal remedies to help manage chronic conditions or for overall health. A report in the latest edition of the Journal of the American College of Cardiology says mixing medicine with herbal products can be dangerous, even deadly.

You've probably heard the warnings about grapefruit juice, that it can increase effects of certain drugs, like beta and calcium channel blockers, putting patients at risk for dangerously low blood pressure or liver toxicity. But there other herbs that can be risky too.

St. John's Wort used to treat depression can also increase heart rate and blood pressure, according to the review, which looked at two nationwide surveys conducted in 1990 and 1997.

"The supplement can in some instances be harmful, but in many more instances interfere with a drug you're taking, making it either far less potent or over potent," said Dr. Richard Stein, American Heart Association.

About half of patients fail to tell their doctors they're taking supplements, which is especially concerning for people taking multiple medications.

"We have no way of knowing which patient is going to have a minor problem or which patient is going to have  a serious problem, in large part because we can't understand how pure and what form the herb they're taking is, and what dose," said Stein.

Some herbal remedies are regarded as food products so they're not subject to the same scrutiny as traditional medications. But a spokesman for the Council for Responsible Nutrition says the review contains inaccuracies.

Dr. Douglas MacKay in a written statement said the potential risk for a drug interaction can be eliminated by speaking openly with your doctor. The review notes that herbs have been used for centuries with many benefits, but that more study is needed to fully understand potential harm when taking them with certain modern medications.