Natural health product-drug interactions: evolving responsibilities to take complementary and alternative medicine into account.

Natural health products (NHPs) (known as dietary supplements in the United States) are a popular form of self-care, yet many patients do not disclose their use to clinicians. NHP-drug interactions are known to occur and can harm patients and affect the efficacy of conventional treatment. Using the example of an HIV-positive adolescent who had been responding well to antiretroviral therapy but then experienced a sudden unexplained deterioration in her condition, we review (1) clinicians' obligation to inquire about complementary and alternative medicine (CAM) use when assessing, treating, and monitoring patients, (2) how clinicians' duty to warn about risks associated with treatment has evolved and expanded, and (3) patients' and parents' responsibility to disclose CAM use. It also addresses the responsibility of hospitals and health facilities to ensure that the reality of widespread CAM/NHP use is taken into account in patient care to effectively protect patients from harm.