Herb-drug interactions and food incompatibilities - A Review of literature

Back ground: Herbs and supplements are major part of alternative therapies. One third of adult population in the developed countries, resort to some kind of alternative therapy. A recent national survey showed that about 60 million Americans use Complementary and Alternative medicine. An estimated 20% of patients who regularly take prescription drugs also take herbal or nutritional supplements. Prior to administration of supplements/herbs it is critical to recognize herb-food-drug interactions. This enhances safe and effective alternative health care to the public domain.

Methods: The literature search has been conducted using classical text books of both Oriental and Ayurvedic medicine and computerized literature search has been done on PubMed, AMED, CINHAL and the Cochrane library (from inception to 2008). The search terms used include herbal medicine, botanical drug, and plant, phytotherapy, in combination with side effects, interaction, incompatibilities and synergistic actions.

Results: The review of the classical text books revealed that there is literature to explain herb-herb interactions, herb-food interactions and food incompatibilities. The computerized literature search showed an increased number of reports on herb drug interactions, although many of them are in the form of case reports with limited clinical observations.

Conclusions: It is very important to understand indications, cautions and contraindications of herbs in order to provide safe and effective healthcare to the public and also educate the public about taking herbs under the supervision of a CAM practitioner. Monitoring of adverse events when herbal medicines are co-administered with drugs could be systematically carried out and potential herb drug interactions should be identified and documented.