Scientific Poster Session III - Case Reports

Case Reports
  Monday, November 13, 2023
  01:00 PM–02:30 PM

Abstract

Introduction: N-acetylcysteine is used in acetaminophen toxicity to prevent acetaminophen-induced liver injury. The use of N-acetylcysteine is considered standard of care. The addition of fomepizole to N-acetylcysteine has been supported only through case reports and animal studies. This case supports emerging evidence regarding the initiation of fomepizole with N-acetylcysteine and subsequent fomepizole dosing in an acute acetaminophen overdose.

Case:

A 33-year-old male presented to the emergency department with stable vital signs (GCS 13), able to follow one-step commands with significant prompting. The patient endorsed a benzodiazepine overdose but was unable to discuss any co-ingestions. The patient’s acetaminophen level was elevated (398 ug/mL), liver enzymes and coagulation labs were within normal limits. Four hours after N-acetylcysteine initiation and a one-time fomepizole dose (15 mg/kg), the acetaminophen level remained elevated at 372 ug/mL and 276 ug/mL after eight-hours. All other labs remained within normal limits.

Fomepizole (15 mg/kg) was re-dosed 14.5-hours after initiation of N-acetylcysteine. After 38-hours of therapy and an acetaminophen level of < 10 ug/mL, N-acetylcysteine was discontinued. The patient returned to baseline with a GCS 15 and all laboratory values within normal limits.

Discussion: Previous case reports demonstrate the addition of fomepizole to N-acetylcysteine in the setting of a massive ingestion or severely elevated acetaminophen concentrations (>500 ug/mL). This case demonstrates initial fomepizole use in an unknown ingestion size and repeat dosing in moderately elevated acetaminophen levels. Fomepizole was successfully added to prevent progression to acute liver injury, demonstrated by lab values remaining within normal limits. The hepatoprotective properties of N-acetylcysteine with fomepizole should be further explored, evaluating initial combination therapy and subsequent dosing parameters.

Conclusion: Animal studies and case reports have demonstrated the addition of fomepizole as a hepatoprotective agent in acetaminophen toxicity. This case adds fomepizole may be administered as initial and as adjunct therapy to prevent acetaminophen-induced liver injury.

Presenting Author

Jennifer Hoh PharmD, BCCCP
University of Louisiana at Monroe

Authors

Erica Hall PharmD
University of Louisiana at Monroe - New Orleans Campus

Timothy Roberts PharmD Candidate
University of Louisiana Monroe