One in six American adults uses herbal products or other natural supplements in addition to prescription drugs, raising concerns about possible adverse interactions.
The Journal of the American Medical Association, JAMA, reports that David W. Kaufman and colleagues at the Slone Epidemiology Unit, Boston University School of Public Health, analysed data from a survey on the use of all medications in the United States - including prescription and over-the-counter drugs, vitamins and minerals, and herbal preparations and other natural supplements.
As older drugs become increasingly available over-the-counter, self-medication is growing ever more popular, the research shows, while at the same time consumption of herbal products and other natural supplements has also grown strongly.
Using data from an ongoing telephone survey, the researchers showed that among 2590 participants aged at least 18 years, 81% used at least one medication per week, 50% took at least one prescription drug and 7% took five or more.
Herbals/supplements were taken by 14% of the population. Among prescription drug users, 16% also took a herbal/supplement, with the rate of concurrent use highest for users of fluoxetine, an antidepressant drug, at 22%. "The substantial overlap between use of prescription medications and herbals/supplements raises concern about unintended interactions," the authors said.
"Reasons for drug use varied widely, with hypertension and headache mentioned most often (9% for each). Vitamins/minerals were frequently used for non-specific reasons such as 'health' (35%). Herbals/supplements were also most commonly used for 'health' (16%)," the report said.
"Identification of usage patterns for the full range of medications, including the reasons for use, provides a basis for improving safety and reducing risks associated with their consumption," the authors concluded.