# Adapting opioid therapy: real-world analysis of switching from methadone to slow-release morphine and back amid COVID-19 supply chain disruptions

## TL;DR

This study shows that switching patients from methadone to slow-release morphine during a supply shortage caused minimal withdrawal and maintained long-term treatment success.

## Contribution

The study provides real-world evidence that slow-release morphine can effectively replace methadone during supply disruptions without harming patient outcomes.

## Key findings

- Patients experienced mild withdrawal symptoms with a mean COWS score of 8.2.
- Retention rates remained high at 97.8% after one month and 89.2% after one year.
- Higher methadone dosages and longer treatment histories correlated with better retention.

## Abstract

This study evaluated the effectiveness and patient outcomes of a temporary switch from methadone to slow-release oral morphine (SROM) during COVID-19-related supply disruptions in Lithuania in 2022.

Data from 231 patients at the Vilnius Branch of the Republican Centre for Addictive Disorders who received SROM for at least two days were retrospectively analyzed. The key metrics included methadone and SROM dosages, withdrawal severity (Clinical Opioid Withdrawal Scale (COWS)), and retention rates at 1, 3, 6, and 12 months post-switch. The data were compared by sex, methadone dosage group (low: 10–60 mg/d, medium: 61–100 mg/d, high: 101–150 mg/d), and clinic attendance frequency. To contextualize long-term outcomes, retention rates were compared with annual program-level data from 2018 to 2024.

Patients received SROM for an average of 8.4 days at an initial methadone-to-SROM ratio of 1:4, which increased to 1:5.23. Withdrawal symptoms were generally mild, peaking at a mean COWS score of 8.2. Women experienced more severe symptoms than men did. After two weeks of SROM therapy, methadone supplies were restored, and patients resumed their original treatment. The retention rates remained high at 1, 3, 6, and 12 months (97.8%, 96.1%, 93.5%, and 89.2%, respectively), with higher retention rates among patients with take-home doses, higher baseline methadone dosages, or longer treatment histories. Long-term program data confirmed that the temporary switch to SROM did not adversely affect overall treatment engagement compared with preceding and subsequent years.

A temporary switch to SROM effectively managed methadone supply disruptions by serving as a viable substitute for methadone, causing minimal withdrawal symptoms and maintaining long-term retention. Coordinated clinical monitoring, institutional protocols, and supportive policy measures ensure continuity of care, emphasizing the value of flexible, personalized treatment strategies during crises.