Symptom-inhibited fentanyl induction (SIFI) for hospitalized patients with opioid use disorder: a retrospective chart review

Abstract Background Symptom-inhibited fentanyl induction (SIFI) is a novel protocol involving the repeated administration of intravenous fentanyl to induce patients onto opioid agonist therapy (OAT). Methods Our aim is to investigate the safety and efficacy of SIFI in patients who use unregulated fentanyl. A retrospective chart review was conducted for patients prescribed the SIFI protocol at Vancouver General Hospital. Outcomes included adverse events, self-directed discharges (SDDs) during or after SIFI, whether primary reasons for admission were addressed, transition to OAT, emergency department (ED) visits or hospital admissions within 30 days of discharge, and SIFI dosing characteristics. Results A total of 17 patient encounters were included, where one patient received SIFI during two separate admissions. SIFI resulted in transient sedation in 3 patients not requiring resuscitation, and no serious adverse events. Compared to admissions in the three months prior to SIFI, the time before leaving hospital for patients increased from mean (standard deviation) of 0.2 (0.6) days to 9 (8.1) days for the entire cohort and to 49.2 (84.6) days in those without SDDs. Total number of SDDs after SIFI was increased compared to before (51% to 65%). Most patients had their primary reason for admission addressed and were observed with lower readmission rates in the month following admission with SIFI. At discharge, 6 patients were on OAT. Conclusions SIFI did not cause serious adverse effects and was associated with longer stays in hospital before SDD. Trial registration This study was registered on ClinicalTrials.gov, #NCT05905367. Registration date 2023-05-30.