Acetylcysteine for treatment of autism spectrum disorder symptoms

Am J Health Syst Pharm. 2015 Nov 15;72(22):1956-9. doi: 10.2146/ajhp150072.


Purpose: Successful use of acetylcysteine to control irritability and aggressive behaviors in a hospitalized adolescent patient with autism spectrum disorder (ASD) is described.

Summary: A 17-year-old Hispanic male with ASD and intellectual disability was hospitalized for inpatient psychiatric treatment due to impulsive and violent behavior. Despite receiving various medications in the initial weeks of hospitalization, including intramuscular lorazepam and diphenhydramine injections (four days a week on average), the patient continued to exhibit aggressive and unpredictable behaviors. Treatment with 20% acetylcysteine oral solution was initiated at a dosage of 600 mg twice daily as an adjunct to quetiapine therapy. Over the next six weeks, reductions in the patient's aggressive behavior, tantrums, and irritability were noted. The use of as-needed medications to control aggression was decreased, and the dosage of quetiapine was lowered from 700 to 400 mg daily over the course of the hospitalization. Acetylcysteine was well tolerated, with no observed or reported adverse effects. Unlike clonidine or guanfacine (other medications used for ASD-related behavioral symptoms), acetylcysteine is not sedating; moreover, it lacks the metabolic, extrapyramidal, and endocrine adverse effects of atypical antipsychotics. Published data from small controlled trials and case reports suggest that acetylcysteine use is associated with improvements in irritability and aggression in prepubertal children with ASD; these therapeutic benefits may be associated with acetylcysteine's glutamatergic, dopaminergic, antioxidant, and anti-inflammatory properties.

Conclusion: Treatment with acetylcysteine improved ASD symptoms, including irritability and aggression, in a teenage patient.

Publication types

  • Case Reports

MeSH terms

  • Acetylcysteine / administration & dosage
  • Acetylcysteine / pharmacology
  • Acetylcysteine / therapeutic use*
  • Adolescent
  • Aggression / drug effects
  • Antioxidants / administration & dosage
  • Antioxidants / pharmacology
  • Antioxidants / therapeutic use*
  • Antipsychotic Agents / administration & dosage
  • Autism Spectrum Disorder / drug therapy*
  • Autism Spectrum Disorder / physiopathology
  • Drug Therapy, Combination
  • Humans
  • Male
  • Quetiapine Fumarate / administration & dosage
  • Treatment Outcome


  • Antioxidants
  • Antipsychotic Agents
  • Quetiapine Fumarate
  • Acetylcysteine