Received: 10 April 2020
Accepted: 28 July 2020
First Online: 8 August 2020
Ethics approval and consent to participate
: The study was approved by the research ethics committee of Isfahan University of Medical Sciences (ethics code no: IR.MUI.REC.1396.2.023). Also, all interviewees gave their verbal informed consent, all names are aliases, and the OUD treatment centers are anonymous.
: Not applicable.
: The authors declare that they have no competing interests.