Illicit synthetic fentanyl is found in increasing proportions of illicit drug samples, and negatively influences how buprenorphine is used on the street to help with subjective withdrawal symptoms. In the clinic, it has been observed among individuals positive for fentanyl that initiation of buprenorphine is difficult. When spontaneous withdrawal, normally the signal that the patient is ready to initiate buprenorphine, and buprenorphine is given, withdrawal symptoms often seem to increase. It is unclear whether this represents precipitated withdrawal versus progressing spontaneous withdrawal, but the standard clinical approach has been to wait for more withdrawal symptoms and time to elapse before trying another test dose. In this population, waiting is a clinically problematic strategy as many patients in continuing withdrawal would resume opioid use rather than try buprenorphine again. To date, there has been one study noting that fentanyl dependent patients are retained at equal rates to patients with heroin dependence, but this study was observational, retrospective and small. An alternative approach to induction would rapidly provide high doses of buprenorphine initially. The theory behind rapid induction would be either that the robust withdrawal observed is actually spontaneous withdrawal, calling for a higher initial buprenorphine dosing regimen, or that some of the withdrawal observed may be precipitated, but rapidly and fully occupying the receptors with partial agonist produces enough agonist effect to subdue precipitated withdrawal. If found to be superior to standard induction, the high dose induction regimen could be immediately implemented in primary care settings. Or, if buprenorphine cannot be initiated for a given patient, a full opioid agonist, namely methadone, may be the best first step, suggesting methadone as a first-line treatment for those dependent on fentanyl and other high potency synthetics. Methadone administration is currently restricted to specially licensed opioid treatment programs and not widely available across clinical settings where buprenorphine can be initiated. If the availability of methadone rescue in this study proves useful, it would support a larger case for regulatory reforms to make methadone more widely available beyond traditional OTPs.

The study proposed here would be the first pilot study to assess the extent that synthetic opioid dependence prevents successful induction with buprenorphine-naloxone. Programs like the Pennsylvania Psychiatric Institute's opioid treatment program have been set up to serve rural and impoverished small urban communities that have become the epicenter of the opioid epidemic. The need to deliver evidence-based treatment effectively is paramount, especially during a window of time in which an individual desiring treatment and having access to that treatment is vanishingly small. A difficult initiation with substantial withdrawal symptoms can derail motivation that can lead to treatment abandonment. A rapid assessment of whether individuals cannot complete buprenorphine-naloxone induction who have been using illicit fentanyl or combination fentanyl with other opioids is a starting point to change management of this growing set of individuals.