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Review indicates similar adverse reactions to St. John’s Wort, prescribed SSRIs

St. John’s Wort had adverse drug reactions comparable to those of the selective serotonin uptake inhibitor fluoxetine, suggesting the herbal treatment may not be the safer option.

“Along with reported therapeutic effects, there have been numerous well-documented cases where adverse effects from herbal preparations have occurred that have been due to dangerous ingredients that have either been added deliberately (eg, heavy metals), inadvertently (pesticides) or accidentally (misidentification of herbs). Other problems have arisen due to adulteration of herbal preparations with prescription medications, or due to inappropriate use of these materials,” study researcher Claire L. Hoban, a PhD student at the University of Adelaide in Australia, and colleagues wrote.

Researchers analyzed post-marketing surveillance data for spontaneously reported adverse drug reactions reported to the Therapeutic Goods Administration between 2000 and 2013 for St. John’s Wort (Hypericum perforatum) and fluoxetine.

Overall, 84 spontaneous adverse drug reactions were reported for St. John’s Wort, compared with 447 for fluoxetine.

The majority of adverse drug reactions reported for St. John’s Wort (45.2%) and fluoxetine (61.7%) affected the nervous system.

The contributing mechanism to adverse drug reactions followed similar patterns for both treatments, either due solely to the treatment directly, or due to drug-drug or drug-herb interactions, pharmacodynamics interaction or pharmacokinetic interaction.

Most adverse drug reactions were mild-to-moderate for both St. John’s Wort and fluoxetine; though severe reactions were more common for St. John’s Wort (19% vs. 6%) and fatal outcomes were more common for fluoxetine (4.9% vs. 0%).

“The proportions of moderate and severe [adverse drug reactions], and the presence of life-threatening [adverse drug reactions] suggest that [adverse drug reactions] to St. John’s Wort may be more serious than widely imagined,” Hoban and colleagues wrote. “The results of this investigation also highlight the importance of consumer awareness regarding the seriousness of the potential side effects and drug interactions of herbal medicines, and the requirement for stringent regulation of herbal medicine products. The Australian public is often unaware that [complementary alternative medicines] are not tested by the [Therapeutic Goods Administration] for efficacy or safety. Increased monitoring of herbal medicine issues and use could see a decrease in the frequency of [adverse drug reactions], and increased reporting of those [adverse drug reactions] that do occur. – by Amanda Oldt

Disclosure: Please see the full study for a list of all authors’ relevant financial disclosures.