Non-prescribed use of methadone and buprenorphine prior to opioid substitution treatment: lifetime prevalence, motives, and drug sources among people with opioid dependence in five Swedish cities

Experiences of non-prescribed use of methadone and buprenorphine are extremely common among those in OST in southern Sweden. As the use is typically driven by pseudo-therapeutic motives, increased access to OST might decrease the illicit demand for these substances. Buprenorphine/naloxone has a lower abuse potential than buprenorphine and should therefore be prioritized as the prescribed drug. Supervised dosage and other control measures are important provisions in the prevention of drug diversion and non-prescribed use among people not undergoing OST.