News Briefs

Researchers Report Adverse Interaction Between Chamomile and Warfarin

Researchers at the McGill University Health Centre (MUHC) in Montreal have documented a severe case of internal hemorrhaging in a patient who drank chamomile tea and used chamomile lotion while taking anticoagulant medication for a heart condition.

Chamomile tea is taken to treat a range of ailments, including toothache, sore throats, digestive problems, and insomnia. Chamomile lotion often is used to treat the skin conditions psoriasis, eczema, and acne, as well as to help soothe insect bites.

The 70-year-old woman was admitted to the MUHC emergency room after using chamomile to help soothe her sore throat. She had been implanted with a mechanical valve and was taking the anticoagulant medication warfarin. Several factors led caregivers to the possibility of a chamomile/warfarin interaction. First, the patient's daughter verified her medications and said there was no possibility of warfarin overdose during the time in question. Second, a consultation with the patient's pharmacist revealed no change in warfarin dosage over the previous 11 months. Review of the patient's other medications also did not reveal any potential interactants with warfarin, and the patient consumed no antiplatelet agents at any time. In addition, the patient said she had not changed her diet in the days before her hospital admission.

The patient, however, revealed that she had been using a chamomile-based skin lotion to help treat her pedal edema. For this, she applied a teaspoon-sized amount to each leg four to five times per day. She also used a camphor-based lotion to ease her chest congestion and drank four to five cups a day of chamomile tea, prepared by adding water to a teaspoon of dried chamomile leaves, to try to ease her sore throat. She usually used both chamomile products once or twice per day, the researchers say.

As a result of the previous questioning and the chamomile use, caregivers linked the occurrence of this hemorrhage to the simultaneous and excessive use of chamomile products.

"We are aware of several herbal products that should not be taken with warfarin, such as garlic, onion, and ginger, but this is the first time we have documented a life-threatening reaction when combined with chamomile," says Louise Pilote, MD, MPH, PhD, an internist and epidemiologist at the MUHC and associate professor of medicine at McGill University. She is also one of the authors of the research, published in the April 25 issue of the Canadian Medical Association Journal.

Warfarin is derived from coumarin, a chemical compound with anticoagulant properties found in many plants, including chamomile. "It seems the chamomile acted synergistically with the warfarin in this case," Pilote says. "Although this is a rare case, it highlights the potential dangers of mixing herbal remedies with physician-prescribed medications."

Because of the possible interaction, the researchers say, patients should be educated about the potential risk of using chamomile products while being treated with warfarin.

Women who Reduce Milk Intake During Pregnancy May Have Smaller Babies

New research shows that women who consumed one cup or less of milk per day gave birth to infants who weighed less than those born to women who consumed more milk, although infant lengths and head circumferences remained similar. Women who restricted milk intake also had statistically significantly lower intakes of protein and vitamin D.

The researchers say that some pregnant women are being advised or are choosing to restrict milk consumption and may not be taking appropriate supplements. The researchers hypothesized that maternal milk restriction during pregnancy, which can reduce intakes of protein, calcium, riboflavin, and vitamin D, might represent a health risk by lowering infant birth weight.

They studied 72 women between the ages of 19 and 45 years who admitted to restricting milk and were attending prenatal programs in Calgary, Alberta, Canada. Using dietary recalls compiled from telephone interviews, the researchers compared these women and their babies with babies to women whose daily milk consumption exceeded 250 mL (1 cup). Birth weight, length, and head circumference were obtained from birth records.

In multivariate analyses controlled for previously established predictors of infant birth weight, the researchers found milk consumption and vitamin D intake both to be significant predictors of birth weight. Each additional cup of milk daily was associated with a 41 g increase in birth weight, and each additional mcg of vitamin D was associated with an 11 g increase. Neither protein, riboflavin, nor calcium intake was found to predict birth weight. The findings of the research were published in the April 25 issue of the Canadian Medical Association Journal.

Absence of vitamin D seems to be driving the results, study co-author Kristine G. Koski, PhD, tells Reuters Health. Koski is director of the School of Dietetics and Human Nutrition at McGill University in Montreal, Canada. The vitamin D intake for the women who restricted milk was still, on average, within the recommended range. This suggests that pregnant women need more than the current "adequate" intake level for vitamin D—5 mcg for adults age 50 and younger, Koski tells Reuters.