Validation and Utility of Drug-Nutrient Interaction and Dietary Supplement Mechanistic Activity in the Natural Medicines Database.

Purpose: The increasing use of dietary supplements by patients with cancer and other chronic diseases requires the systematized review of potential interactions between prescription drugs and nutrients from supplements by health care and clinical research teams. Dietary supplement interaction databases are positioned to fill a gap in quantifying potential risks for patients, although none have been assessed for reliability in data interpretation. The NatMed database, a source for comprehensive reports on mechanistic and safety data for dietary supplement ingredients, was evaluated for use in future investigations.

Methods: Data from NatMed were retrieved using licensed end points for ingredient monographs with drug-nutrient interactions with doxorubicin across five pharmacokinetic and metabolic pathways, and for ingredient monographs with antioxidant activity. Interactions between dietary supplements and doxorubicin treatment and antioxidant monographs were independently reviewed and characterized by clinical pharmacists. Cohen's K was used to measure interrater reliability and the degree of agreement between pharmacists.

Results: Three hundred fifteen potential interactions with doxorubicin (n = 115 monographs) and 455 other antioxidant ingredients were identified and reviewed by clinical pharmacists. There was substantial to near-perfect agreement for drug-nutrient interactions with doxorubicin (Cohen's K = 0.64-0.85) and for antioxidants (Cohen's K = 0.84). A small proportion of retrieved monographs were not validated by the clinical pharmacists for interactions with doxorubicin (n = 20 occurrences, 6.4%) or for antioxidant activity (n = 28, 6.2%).

Conclusion: A high degree of reliability in data on dietary supplement interactions with doxorubicin and mechanisms of action suggests NatMed may be a dependable source of data for future investigators. Additional procedures including independent data validation and use of multiple dietary supplement interaction databases will strengthen the quality of findings in future studies.