The uncertainty associated with designation of required clinical endpoints to be used in clinical trials of medications for cocaine addiction was cited as a market barrier, though not a major one. Two pharmaceutical company interviewees identified this ambiguity as a potential barrier, and one company representative expressed some concern that "chasing a moving target" could increase the costs of conducting clinical trials. However, the pharmaceutical company interviewees were not aware of the FDA's current efforts to update its draft guidance for trials of drugs to treat cocaine addiction.
The case study of naltrexone demonstrated the difficulty of convincing providers and patients that a reduction in use of heroin or alcohol can result in favorable health outcomes. Although naltrexone blocks the effects of both heroin and alcohol, it does not prevent patients from using these substances. Researchers noticed that because patients using naltrexone did not experience the euphoric effects of heroin or alcohol, they had less incentive to inject heroin or drink alcohol, and their volume of use was reduced. Many provider and patient support groups have expressed that total abstinence is the only acceptable cure.