Use of St. John's Wort in potentially dangerous combinations.

OBJECTIVES

The objective of this study was to assess how often St. John's wort (SJW) is prescribed with medications that may interact dangerously with it.

DESIGN

The study design was a retrospective analysis of nationally representative data from the National Ambulatory Medical Care Survey.

SETTINGS: The study setting was U.S. nonfederal outpatient physician offices.

SUBJECTS: Those prescribed SJW between 1993 and 2010 were the subjects.

OUTCOME MEASURES: The outcome measures were medications co-prescribed with SJW.

RESULTS

Twenty-eight percent (28%) of SJW visits involved a drug that has potentially dangerous interaction with SJW. These included selective serotonin reuptake inhibitors, benzodiazepines, warfarin, statins, verapamil, digoxin, and oral contraceptives.

CONCLUSIONS

SJW is frequently used in potentially dangerous combinations. Physicians should be aware of these common interactions and warn patients appropriately.