Herb-drug interactions: interactions between kava and prescription medications

Patients over age 50 typically present with one chronic disease per decade. Each chronic disease usually requires long-term drug therapy, meaning most older patients require several drugs to control their conditions and/or maintain their health. Simultaneously, the use of complementary and alternative medications (CAM) has increased in the United States over the last 20 years, reaching 36% in 2002; herbal medicine use accounts for approximately 22% of all CAM use. Older adults often add herbal medicines to medications prescribed by their physicians, yet do not always inform the physician. The drug metabolizing enzyme systems process all compounds foreign to the body including prescription drugs and herbal medications. Therefore use of both medicinals simultaneously has a potential for interactions of an adverse nature. This review, which will discuss kava, is one in a series covering the documented interactions between herbal medicines with proven efficacy and prescription drugs.