Natural Health Product Interactions with Medication

Abstract

Natural health products (or dietary supplements) refer to those products found in oral dosage forms, containing 1 or more active ingredients considered to be a nutrient, an herbal product, or any other nonnutrient/nonherbal substance. Their use continues to increase in the general population and in patients seen by nutrition support clinicians. Aside from an appraisal of product safety and effectiveness, attention should be paid to the potential for these product ingredients to interact with medication. Estimates are that at least 15 million adults in the United States are at risk for supplement-drug interactions. These can occur through both pharmacokinetic and pharmacodynamic mechanisms. This review describes the influence of dietary supplements on both the disposition and the effect of medication and provides numerous examples. Patients at greatest risk for interactions are those with chronic disease, who use multiple medications-particularly those with a narrow therapeutic range-have genetic variants in drug metabolism, impaired organ function, and are at either end of the age spectrum. Knowledge of the specific effects on drug absorption, metabolism, and effect is still incomplete. Relative to the large number of possible interactions between supplements and medication, only a small number of combinations have been examined or reported. The greatest limiting factor remains the quality or reliability of the existing evidence, as many widely accepted interactions are only theoretical based either on in vitro data or known pharmacology. A distinction needs to be clearly drawn between "documented" interactions and "potential" interactions. Although drug-drug interactions have been widely recognized, supplement-drug interactions may be as important to recognize, report, and manage.

The Use of Complementary and Alternative Medicine in Pediatrics

“…[70][71][72][73][74][75][76][77][78][79] Because of regulations differing from those governing the use of pharmaceuticals, there are concerns about the purity and potency of herbal products and other dietary supplements sold in the United States. Product quality is influenced by many factors, including which portion of the plant is used (ie, root, stem, leaves, flowers), the time of harvest (ie, young versus old plants), the handling of the product, and proper identification of the plant.…”

Drug Interactions With Herbal Medicines

“…56 Use of HM and a prescription drug has the potential to decrease or increase the effect of the drug. 57 Eleutherococcus senticosus Rupt. & Maxim (Araliaceae), for example, increased the serum concentration of digoxin.…”

Drug–Nutrient Interactions: A Broad View with Implications for Practice

“…Qualitative or quantitative biomarker measures of drug action or of nutrition status help to define pharmacodynamic interactions. These interactions can be antagonistic (eg, warfarin with vitamin K, reduces international normalized ratio) or additive in effect (eg, warfarin with vitamin E, increases bleeding risk) (40).…”