NCT04725383.

Study name	Amitriptyline for repetitive behaviors in autism spectrum disorders
Methods	12‐week parallel trial of amitripyline versus placebo
Participants	Inclusion criteria male and female aged 6‐17 years diagnosis of ASD IQ > 35 Exclusion criteria: an allergy to amitriptyline absence of a reliable caregiver previous neuroleptic malignant syndrome seizures in the past 3 months bipolar disorder current or past psychosis unstable medical illness previous adequate treatment with amitriptyline using other psychotropic medications apart from melatonin for sleep or lorazepam 1 mg as needed up to once a day Target sample size: 30 participants Location/setting: USA
Interventions	Intervention: "Subjects will receive active amitriptyline compounded into look‐alike capsules to resemble placebo capsules. Dosing will be as tolerated, up to a maximum of 100mg/day or 1.5mg/kg/day, for 12 weeks." Comparator: "Subjects in this arm will receive placebo compounded into capsules that resemble the compounded amitriptyline capsules, up to 4 capsules a day, for 12 weeks."
Outcomes	Primary outcomes: irritability (measured using the ABC‐I (Aman 1985) self‐injurious behaviour (measured using the Repetitive Behaviour Scale) (Bodfish 2000) Secondary outcomes: none reported Timing of outcome assessments: baseline and 12 weeks (endpoint)
Starting date	First registered January 2021
Contact information	Jessica Hellings Jessica.Hellings@tmcmed.org
Notes	Source of funding: sponsored by the University of Missouri, Kansas City Conflicts of interest: details not provided