Clinical outcomes of single-agent mifepristone exposures reported to US Poison Centers: a ten-year review of the National Poison Data System® (2015-2024).

INTRODUCTION

Mifepristone is a 19-nor steroid that functions as a progesterone and glucocorticoid receptor antagonist with multiple uses approved by the United States Food and Drug Administration. Although its safety with therapeutic use is well established, data describing single-agent mifepristone toxicity is limited.

METHODS

This was a retrospective review of single-agent mifepristone exposures reported to the National Poison Data SystemⓇ from 1 January 2015, through 31 December 2024. Cases involving co-exposures, combination products, or unrelated outcomes were excluded. Demographic characteristics, exposure circumstances, clinical effects, management sites, therapies, and outcomes were analyzed using descriptive statistics.

RESULTS

Of 106 single-agent mifepristone exposures misoprostol identified, 77 patients met inclusion criteria. Patients were categorized as children ≤12 years old or adolescents/adults >12 years old. The mean patient age was 18.1 years (range 5 months-71 years), and 76.6% were female. Eight patients (10.3%) were pregnant. Most exposures were acute (93.5%), unintentional (64.9%), and occurred by oral ingestion (94.8%). The most common effects were nausea or vomiting (7.8%), abdominal pain (5.2%), and dizziness or vertigo (3.9%). The most common therapies were dilution or irrigation (13%), intravenous fluids (2.6%), steroids (2.6%), and antihistamines (2.6%). Two patients were admitted to non-critical care units, and there were no major effects or deaths. Among pregnant patients, no fetal deaths or significant maternal complications were reported.

DISCUSSION: Mifepristone exposures reported to United States poison centers in our study were uncommon and typically associated with mild, self-limited symptoms. No major effects, critical care admissions, or deaths were identified.

CONCLUSION

These findings suggest that single-agent mifepristone exposures rarely result in major effects and generally follows a benign clinical course.