This study presents an example of when the government introduced a regulation that did not coincide research, professional ethics, responsibility or commitments, and led to a conflict between professionals and rulers. In the Swedish statutes regulating opioid maintenance treatment (OMT), a unique definition of the term opiate-dependency, the opiate rule, was introduced in 2010—restricting the target group for treatment. Persons dependent on other opioids than heroin, morphine or opium (HMO) from now on were to be denied OMT. The regulation was enforced without support from research and against protests from clinics and referral agencies, an approach that previously not been problematised in research. This study investigates, through interviews with 13 persons in key positions in OMT, how clinical praxis responded and what strategies were developed. Healthcare providers were found to increase their efforts to find references to HMO in the journal. If HMO were not found, opioid-dependent patients were to be denied treatment and “negative merit” was provoked. Clinics developed strategies to provide ”unofficial OMT” or intentionally violated the regulation by admitting those without HMO documentation in OMT. These strategies were used with reference to evidence in research, professional evaluation of the medical treatment needs, and ethical obligations.