Clinically Relevant Safety Issues Associated with St. John’s Wort Product Labels

Background. St. John’s wort (SJW) interacts with drugs including cyclosporine, indinavir, and warfarin. Healthcare professionals (HCPs) are often unaware of these interactions. The product label is one source of information and inclusion of interaction information on SJW labels is associated with more appropriate counseling being dispensed. Objective. To evaluate clinically relevant safety information on SJW product labels. Methods. Categories of label safety issues were established as: 1) drug interactions, 2) contraindications, 3) therapeutic duplication, and 4) general considerations. Evaluations of labels were performed. Descriptive statistics were used to summarize and Chi square and ANOVA were performed to detect a difference in product scores. A post-hoc Duncan test was conducted to examine the data for differences in label scores between individual products. Results. The percentage of the 74 SJW products with label information present was: SJW-HIV (8.11%), SJW-immuno-suppressants (5.45%), SJW-oral contraceptives (8.108%), SJW-warfarin (5.41%), bipolar (1.35%), antidepressants (22.97%), phototoxicity (51.35%), and consult HCP (87.84%). The mean number of safety warnings included on a product label was 1.84 (range 0-8). Both ANOVA (p=0.005) and Chi square (p=0.008) showed that differences existed between the label scores of SJW products. The post-hoc Duncan test revealed that the scores of three products were statistically superior in terms of completeness (p=0.04). Conclusion. The majority of SJW product labels inadequately address safety issues. A few products provide an acceptable amount of safety information, which could enhance the quality of counseling by HCPs. However, the greatest benefit may be if the FDA re-examined labeling requirements of dietary supplements.