A Case Series Demonstrating the Feasibility of Microdosing as a Bridging Method to Enable a Comfortable and Effective Transition From Prescribed Methadone to Buprenorphine ORT (Opiate Replacement Therapy), Without Initial Methadone Dose Reduction or Cessation, in UK Community Addiction Settings

TL;DR

This study shows that patients on methadone can safely switch to buprenorphine without stopping methadone, reducing withdrawal risks in community settings.

Contribution

A new microdosing bridging method enables methadone-to-buprenorphine transition without dose reduction or abstinence.

Findings

12 patients transitioned safely without precipitated withdrawal or adverse effects.

The method works for methadone doses up to 90 ml daily in community settings.

Buprenorphine was initiated via patches and gradually increased over 6–7 days.

Abstract

Aims: For patients prescribed methadone wishing to access buprenorphine ORT, the current practice is to reduce the methadone dose to 30/40 ml and cessation of methadone for 48 hrs prior to the switch. This exposes these patients to risk of psychological, physical distress or relapse into non-prescribed opiate use.

Using guidance published by the Canadian Journal of Addiction we adapted this to a local UK setting to evaluate its implementation into regular service provision.

We aim to demonstrate effective transition, in a series of patients prescribed methadone onto sl (sublingual) buprenorphine, without adverse effects/precipitated withdrawal or the requirement of methadone dose reduction nor 48 hour abstinence from methadone, in community-based settings.

Methods: We collected outcomes on 12 patients (dose range 26 ml – 90 ml of methadone daily), 12 of whom successfully transitioned from methadone to buprenorphine ORT via buprenorphine Microdosing Bridging Method.

We enquired and assessed for precipitated opiate withdrawal symptoms using a daily modified SOWS/COWS and psychological response throughout the transition period.

Patients were initiated onto buprenorphine initially using transdermal 20 mcg/24 hr buprenorphine patches over the first 48 hrs of treatment, after which urine was tested. Once the urine screen showed buprenorphine, oral initiation of sublingual buprenorphine began on Day 1 at 400 mcg daily and increased according to the following schedule:

Day 2: Usual dose methadone daily, buprenorphine 0.8 mg.

Day 3: Usual dose methadone daily, buprenorphine 1.2 mg.

Day 4: Usual dose methadone daily, buprenorphine 1.6 mg.

Day 5: Usual dose methadone daily, buprenorphine 2.0 mg.

Day 6: Usual dose methadone daily, buprenorphine 4 mg daily.

Day 7: Usual dose methadone daily, buprenorphine 6 mg daily.

Throughout this period, the patients’ methadone dose remained at their pre-transition dose. The last dose of methadone was administered when the patients were administered 6 mg sl buprenorphine daily on Day 6. The following day, patients were administered 8 mg sl buprenorphine with subsequent dose titration to achieve optimal daily dose.

Results: 12 patients achieved the transition from methadone to buprenorphine without experience of precipitated opiate withdrawal or adverse psychological effect.

Conclusion: Transition from methadone to sl buprenorphine without requiring prior dose cessation or reduction of methadone up to 90 ml daily is safe, effective and practical in a community-based and acute care setting. This provides methadone ORT patients the option of accessing buprenorphine ORT over a short period of time (10–14 days) without the experience of precipitated opiate withdrawal, and can be undertaken in a variety of community settings.