Title: Prophylactic Effect of N-Acetylcysteine in an Adolescent With Trichotillomania After Acetaminophen Overdose
Abstract: 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. In acetaminophen overdose, NAC is the drug of choice for treating potentially fatal hepatotoxicity, with nearly 100% efficacy if administered within 8 hours of ingestion. Recently, there is some evidence suggesting that NAC may be helpful in treating body-focused repetitive behavior disorders including trichotillomania.1Lee D.K. Lipner S.R. The potential of N-acetylcysteine for treatment of trichotillomania, excoriation disorder, onychophagia, and onychotillomania: An updated literature review.Int J Environ Res Public Health. 2022; 19: 6370https://doi.org/10.3390/ijerph19116370Crossref PubMed Scopus (5) Google Scholar The idea of coformulating acetaminophen with NAC as a protection against accidental or intentional acetaminophen toxicity has been previously suggested.2Serdenes R. Graham 3rd, J. Evaluating the psychiatric benefits of formulating acetaminophen with N-acetylcysteine.Front Psychiatry. 2020; 11564268https://doi.org/10.3389/fpsyt.2020.564268Crossref PubMed Scopus (3) Google Scholar Currently, literature examining outcomes of patients taking daily NAC who also experience subsequent acetaminophen toxicity is sparse. One case report found that a 66-year-old female patient taking a mental health supplement containing NAC subsequently overdosed on acetaminophen, yet her liver enzymes remained stable. This highlighted a potentially prophylactic role for NAC in intentional acetaminophen overdoses.3Soliman M. Soliman Y. Gurell M. Long live the liver! Accidental prophylaxis with N-acetylcysteine in intentional acetaminophen overdose: 2401.Am J Gastroenterol. 2018; 113: S1340Google Scholar In the following case of a 16-year-old female patient who overdosed on acetaminophen yet also showed stable liver function testing, the patient had been taking over-the-counter NAC during the week before her overdose due to a history of trichotillomania. This case thus highlights a potential role for prophylaxis with NAC in adolescents who overdose on acetaminophen. A 16-year-old girl presented to the emergency department after an acetaminophen overdose in an attempted suicide. The patient had a past psychiatric history of major depressive disorder and posttraumatic stress disorder. She was being treated with sertraline 125 mg daily with limited improvement in symptoms. During the previous 6 months, the patient had experienced multiple traumatic life stressors. This culminated in a suicide attempt in which the patient ingested approximately 100 tablets of acetaminophen 500 mg. The patient also had a history of trichotillomania since childhood. In the months before the overdose, her hair pulling behaviors worsened due to anxiety. To treat the hair pulling, she had been taking 600 mg twice daily of over-the-counter NAC beginning the week before the overdose, after her mother had read that it could be helpful. Several hours after ingesting the acetaminophen, the patient experienced intense stomach pain and repeated vomiting. On presentation to the emergency department, her acetaminophen level was 80 μg/mL; however, her complete metabolic panel showed no early elevations in liver enzymes (Table 1). The patient was admitted, and intravenous NAC therapy was initiated. She had no further episodes of vomiting, abdominal pain, tachycardia, or confusion. The psychiatry consultation service met the patient on the first day of her hospitalization and was surprised that her symptoms appeared so mild. She was comfortably seated upright in bed, was alert and fully oriented, denied any ongoing physical symptoms, and was tolerating oral intake without issue. The primary pediatrics team agreed that her recovery was more rapid than anticipated following such a significant overdose. Consent was obtained from the family for this report.Table 1Changes in the Patient’s Liver Function Tests During Emergency Department StayMarker10 h after overdose34 h after overdoseNormal or safe rangeAcetaminophen80<1515-30 μg/mLAST262110-42 IU/LALT171910-60 IU/LPT12.7N/A11.6-15.2 sPTT28N/A24-37 sINR0.9N/A0.9-1.1Total bilirubin<0.2<0.20.1-1.2 mg/dLAlkaline phosphatase805967-372 IU/LNote: ALT = alanine aminotransferase; AST = aspartate aminotransferase; INR = international normalized ratio; N/A = not available; PT = prothrombin time; PTT = partial thromboplastin time. Open table in a new tab Note: ALT = alanine aminotransferase; AST = aspartate aminotransferase; INR = international normalized ratio; N/A = not available; PT = prothrombin time; PTT = partial thromboplastin time. The landmark study of acetaminophen poisoning and toxicity was done in 1975 by Rumack and Matthew,4Rumack B.H. Matthew H. Acetaminophen poisoning and toxicity.Pediatrics. 1975; 55: 871-876Crossref PubMed Google Scholar who developed a nomogram of acetaminophen levels and time following overdose to predict the risk of toxicity. By plotting serum acetaminophen levels against the time of ingestion, clinicians can assess the likelihood and severity of hepatotoxicity caused by the overdose. Our patient had a serum acetaminophen level of 80 μg/mL, which was collected at 10 hours after ingestion. The threshold serum acetaminophen level for treatment at 10 hours following ingestion is 53.03 μg/mL. It also predicts that the risk for serious toxicity would occur at the threshold level of 70.71 μg/mL.