Initiation and Rapid Titration of Methadone and Slow-Release Oral Morphine (SROM) in an Acute Care, Inpatient Setting: A Case Series

Background: Methadone titration in an outpatient setting typically involves initiation with subtherapeutic doses with slow titration to mitigate the risks of respiratory depression and overdose. In pregnancy, subtherapeutic doses of methadone and slow titrations are associated with poorer outcomes in terms of retreatment retention and ongoing illicit opioid use. We aim to describe rapid titration of OAT in an inpatient setting for pregnant injection opioid users with high opioid tolerance secondary to a fentanyl-based illicit drug supply. Methods: Retrospective case series of patients admitted to a tertiary center with a primary indication of opiate withdrawal and treatment for severe opioid use disorder in pregnancy. Results: Twelve women received rapid methadone titrations with or without slow-release oral morphine for opioid use disorder during a total of fifteen hospital admissions. All women included in the study were active fentanyl users (12/12). Methadone dosing was increased rapidly with no adverse events with a median dose at day 7 of 65mg (IQR 60-70mg) and median discharge dose of 85mg (IQR 70-92.5mg). Slow-release oral morphine was used in half of the titration admissions (8/15) with a median dose of 340mg (IQR 187.5-425mg) at discharge. The median length of admission was 12 days (IQR 9.5-15). Conclusions: A rapid titration of methadone was completed in an inpatient setting with or without slow-release oral morphine, without adverse events showing feasibility of this protocol for a pregnant population in an inpatient setting. Patients achieved therapeutic doses of methadone (and/or SROM) faster than outpatient counterparts with no adverse events.