Potential drug interactions with dietary and herbal supplements during hospitalization.

Dietary and herbal supplements (DHS) are widely used in the general population, including during hospitalization. Yet, their potential interactions with prescription drugs have seldom been delineated among inpatients. We aimed to evaluate potentially dangerous interactions of DHS with prescribed medications among inpatients. This was a cross-sectional prospective study involving a cohort of patients hospitalized in 12 departments of a public academic medical center (Bnai Zion Medical Center, Haifa, Israel) from 2009 to 2014. DHS users were determined via a questionnaire. The Natural Medicine database was used to search for potential DHS-drug interactions for identified DHS, and the clinical significance was evaluated using Lexi-interact online interaction analysis. Medical files were assessed for documentation of DHS use. Univariate and multivariate logistic regression analyses were used to characterize potential risk factors for DHS-drug interactions. Of 927 patients consenting to answer the questionnaire, 458 (49 %) reported DHS use. Of these, 215 (47 %) had at least one potential interaction during hospitalization (759 interactions). Of these interactions, 116 (15 %) were potentially clinically significant. Older age [OR = 1.02 (1.01-1.04), p = 0.002], males [OR = 2.11 (1.35-3.29), p = 0.001] and increased number of used DHS [OR = 4.28 (2.28-8.03), p < 0.001] or drugs [OR = 1.95 (1.17-3.26), p = 0.011] were associated with potential interactions in DHS users. Physicians documented only 16.5 % of DHS involved in these interactions in patients' medical files. In conclusion, a substantial number of inpatients use DHS with potential interactions with concomitant medications. Medical staff should be aware of this, question patients on DHS usage and check for such interactions.