Prophylactic Effect of N-Acetylcysteine in an Adolescent With Trichotillomania After Acetaminophen Overdose.

N-Acetylcysteine (NAC) is an essential drug for the treatment of acetaminophen overdose, with nearly 100% efficacy if delivered within 8 hours of ingestion. In addition to preventing hepatotoxicity following an overdose, there is some evidence that NAC may be effective in the treatment of trichotillomania, onychophagia, onychotillomania, and excoriation disorder. Here we report a 16-year-old female patient with an acetaminophen overdose who presented to the emergency department with normal liver function testing, despite ingesting approximately 100 tablets of acetaminophen 500 mg. The patient also had a history of trichotillomania and had been taking 600 mg twice daily of over-the-counter NAC for the week before the overdose. Therefore, the over-the-counter NAC treatment regimen may have serendipitously served as a prophylactic measure against hepatoxicity in her acetaminophen overdose.