Black Cohosh Interactions with Prescription Medications Associated with Serotonin Toxicity and Rhabdomyolysis: A Case Report.

BACKGROUND: Serotonin toxicity is a well-described phenomenon that is commonly attributed to a variety of drug-drug combinations. Some unregulated herbal supplements have been implicated in the onset of serotonin toxicity, however, there is currently minimal literature available on the potential for black cohosh to contribute to rhabdomyolysis and serotonin toxicity, in spite of its known serotonergic properties.

CASE REPORT: A middle-aged woman presented to the emergency department with serotonin toxicity and rhabdomyolysis shortly after taking black cohosh supplements in the setting of long-term dual antidepressant use. The serotonin toxicity and rhabdomyolysis resolved with IV fluids, benzodiazepines, and discontinuation of the offending drugs. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Patients are sometimes not aware of how over-the-counter supplements might interact with their prescription medications. Female patients taking black cohosh to manage hot flashes and menopausal symptoms could be at risk for developing rhabdomyolysis and serotonin toxicity if they are also taking other serotonergic agents.