A study, published in yesterday's issue of American Journal of Obstetrics and Gynecology, underlines once again that health care providers need to spend more time asking about medication usage to help patients avoid interactions between drugs and herbal medicines.
"We really need to inquire better about patients taking herbal and over-the-counter medications," said Dr Timothy Tracy, a professor at the University of Minnesota College of Pharmacy, the University of Minnesota Center of Excellence in Women's Health and one of the article's authors. "The care providers need to ask, and patients need to tell. Neither one is doing a good job."
Among the more than 570 study participants, 92 per cent took prescription medications, and 96.5 per cent self-medicated with an over-the-counter medication. Furthermore, 59.1 per cent of study participants used herbal supplements.
Researchers also found patients may not mention medications to the physician unless that physician had prescribed the drug. For example, patients did not always tell the gynecologist they were taking high blood pressure medication prescribed by another physician.
"Sometimes, patients don't associate their disease and medication with the individual physician they're seeing at any given time if the physician is not the one treating that condition or if they didn't prescribe the medication," said Tracy.
Students interviewed study participants using a three-step process, asking patients open-ended questions about what medications they take. The interviewer then conducted a system-by-system analysis, asking patients whether they took any medications for situations such as headaches, upset stomachs or achy joints. The patients were then presented with a list of common medication, including prescription, over-the-counter, vitamins and herbal supplements, and asked whether they took any of those medications.
Researchers found that every set of questions uncovered additional medications patients did not initially report. They also discovered that while a patient may report that she is taking a medication during the first visit's interview, she failed to mention it on subsequent visits without prompting.
The interviews were conducted during a 42-month period. During the study, 567 patients had 776 interviews. Patients who had multiple visits during that time frame were interviewed multiple times. The interviews were conducted following women's visits to their gynecologist. Only non-pregnant women were interviewed.
The data revealed several potentially serious drug interactions. The most commonly prescribed medication was antibiotics, some of which are thought to reduce the efficacy of birth control pills.
Researchers also found that nearly 25 per cent of patients took medications for anxiety, depression or other mental health issues. Of patients who used oral contraception, 2.3 per cent took St. John's wort, which can reduce the efficacy of the birth control pill.
The study also found several women taking prescription antidepressants also self-medicated with St. John's wort, an herbal supplement commonly used to treat depression, which has been shown to have potentially harmful interactions with prescription antidepressants