Patient Experience of Withdrawal During Methadone-Buprenorphine Transfer: A Prospective Cohort Study

Methadone-to-buprenorphine transfers (MBT) are increasingly common as buprenorphine use expands. Evidence describing patient experience of withdrawal during MBT in real-world populations is limited. This study aimed to characterise withdrawal trajectories during MBT and examine whether psychosocial and clinical factors influence the severity or timing of withdrawal.

This analysis used data from a prospective, non-randomised clinical trial comparing low-dose and stop-and-start MBT techniques (n = 117). Covariates included methadone dose, duration on methadone, transfer setting, study arm, withdrawal expectancy, psychological distress, substance use and unstable housing. Withdrawal was assessed daily using the Clinical Opioid Withdrawal Scale (COWS) and Short Opiate Withdrawal Scale.

Ninety-four participants (80.3%) completed transfer. Withdrawal followed a consistent trajectory across the cohort, peaking around Day 5. Psychosocial and clinical characteristics-including unstable housing, substance use, psychological distress and methadone dose-were not associated with withdrawal severity or timing. Compared with stop-and-start transfer, low-dose transfer was associated with a delayed and larger increase in objective withdrawal: peak COWS occurred 2.3 days later (95% CI 0.3-4.3) and the largest one-day increase was 3.8 points higher (95% CI 0.5-7.0).

Patient factors often considered barriers to MBT were not associated with withdrawal severity or timing. Low-dose transfer was associated with a delayed and slightly higher withdrawal peak but did not reduce overall transfer success. These findings suggest that withdrawal during MBT follows a broadly similar trajectory across patients with differing psychosocial complexity. Planning for expected withdrawal, rather than selecting patients based on perceived complexity, may be more clinically relevant.