Adjunctive Effects of Psilocybin and Buprenorphine

The primary objective of this clinical trial is to determine the safety of psilocybin in adult patients with opioid use disorder concurrently taking buprenorphine/naloxone (Suboxone®).

Eligible participants will be adults with opioid use disorder (OUD) who have been demonstrated to be stable on a daily buprenorphine/naloxone dose. Recovery status will be verified by the participant's community-based prescriber. After psychological screening and at least 6 hours of preparatory counseling and preparation for the psilocybin dosing, set, and setting, each participant will ingest 1 oral dose of psilocybin. All dosing sessions will be attended by 2 specially trained guides, in a dedicated Clinical Research Facility. After eight hours of observation in the dosing room, the participant will be kept overnight in the hospital Clinical Research Unit, and complete an integration session with a psychologist before discharge to home. Approximately 4 weeks after the first dose, the participant will receive a second oral dose of psilocybin, with the same length of observation.

Participants who have been administered the first dose but decline to receive the second dose will remain evaluable. At study termination, their active study participation will end, but completion of the 28 day post-dose follow up will be requested.

The primary endpoint is the assessment of the safety of concurrent administration of buprenorphine and naloxone (eg., Suboxone®) and psilocybin as determined by physiological measures (ECG, respiratory rate, blood pressure, body temperature, and blood oxygen saturation) and validated clinical and self-report measures (Clinical Opiate Withdrawal Scale (COWS), Opioid Craving Scale (OCS), Timeline Follow-Back (TLFB)).