Trial design and setting
This was a 12‐week, randomized, double‐blind, placebo‐controlled, parallel‐group clinical trial of NAC in participants with SUD under MMT who were referred to a university‐affiliated outpatient SUD clinic (Soltan Mirahmad) in Kashan, Iran. The Soltan Mirahmad clinic is a center that is certified for the treatment and diagnosis of SUD. The personnel include a Ph.D. addiction expert, a general physician, an experienced psychiatrist, well‐trained nurses, and a clinical psychologist. The World Medical Association Code of Ethics (Declaration of Helsinki) was considered by the Research Ethics Committee of Kashan University of Medical Sciences for study approval 