-- St. John's Wort is a best selling herbal product, often used to treat depression...but the medical community issued a warning Tuesday that taking St. John's Wort and birth control pills could lead to a surprise event, CBS News Correspondent Lisa Hughes reports.
For millions of women who don't want to get pregnant, oral contraceptives are the answer. Studies show that, taken properly, the pill is more than 90 percent effective. But researchers now say that effectiveness may be cut in half by St. John's Wort.
Dr. Stephen Piscitelli led the research at the National Institutes of Health. His team tested the effects of St. John's Wort on an anti-AIDS drug. St. John's Wort reduced the drug's effectiveness 50-to-80 percent.
"It's possible that St. John's Wort could decrease the effectiveness of the oral contraceptive and there could be the...birth of a child," said Piscitelli.
Dr. Piscitelli says it's too soon to know whether some unplanned pregnancies might be blamed on the interaction between the pill and the herbal remedy or whether there might be a baby boom as a result. But the FDA has posted a public health advisory on its Web site--not just for women on the pill.
NIH researchers say St. John's Wort may reduce the effectiveness of other drugs including heart medication. And they suspect this study reflects only the tip of the iceberg.
"I think this has far-reaching implications. There are many drugs that might be affected by St. John's Wort," said Piscitelli.
And other herbal remedies may have the same effect. Tests are already underway on garlic and melatonin.
Bottom line--tell your doctor or pharmacist about everything you're taking: medicines, over-the-counter pills and herbal remedies. Volunteer the information even if you're not asked. That may be the only way to find out whether you're taking one product that's reducing the effectiveness of another.
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