Transitioning From High-dose Methadone to Buprenorphine Using a Microdosing Approach: Unique Considerations at ASAM Level 3 Facilities.

Transitions from high-dose methadone to buprenorphine for treatment of opioid use disorder (OUD) present risk of precipitated withdrawal related to the introduction of a high-affinity partial agonist at the mu-opioid receptor after occupancy by a lower-affinity full agonist. Various strategies have been explored to maintain patient stability during this process, including microdosing buprenorphine. Current literature lacks consensus on an optimal setting and strategy for initiating a buprenorphine microdosing protocol and gives little detail on patients' conditions after the acute transition period. We report a 6-day microdosing transition from methadone 100 mg directly to sublingual buprenorphine, followed by a 20-day period of monitoring and additional treatment. This patient tolerated a sublingual buprenorphine microdosing protocol while using supportive medications with a peak Clinical Opiate Withdrawal Scale score of 6. The patient's most significant withdrawal symptoms occurred several days after completion of the microdosing process. This case demonstrates the feasibility of using a transmucosal buprenorphine formulation in microdosing transitions from high-dose methadone directly to buprenorphine, and highlights the utility of a medically monitored intensive inpatient setting (American Society of Addiction Medicine level 3.7) in providing appropriate monitoring and treatment during and after a microdosing transition.