Effects of Switching From Racemic Methadone to R-methadone on QTc Intervals

Oslo University Hospital10 enrolled

Overview

Effects of switching from racemic methadone to R-methadone on serum methadone concentrations and QTc intervals

Racemic methadone may prolong the QTc interval, which is associated with fatal arrhythmias. In vitro studies have shown that R-methadone has less inhibitory effect than S-methadone on the voltage-gated potassium channel current, and is thus thought to have less effect on the QTc interval. The investigators hypothesized that switching from racemic to R-methadone would reduce the methadone serum concentration and also its effect on the QTc interval.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Adverse Drug Effect Drug Effect Heart Arrhythmia

Interventions

Same individuals treated with racemic methadone and switched to levomethadone (R-methadone)DRUG

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Stabilized on daily methadone dose * Not using other drugs of abuse * QTc-time recorded automatically, patient inclusion if QTc interval was greater or equal to 450 ms * Older than 18 years * Can sign and understand a written Consent Exclusion Criteria: * Can not cooperate regarding observed daily drug intake * Serious psychiatric disease * Untreated serious somatic disease * Pregnancy

Locations (3)

Department of Pharmacology , Oslo University Hospital

Oslo, Norway

Department of Pharmacology and Department of Substance Use Disorder, Oslo University Hospital

Oslo, Norway

Department of Substance Use Disorder, Oslo University Hospital

Oslo, Norway

Outcomes

Primary Outcomes

Effects of switching from racemic methadone to R-methadone on serum methadone concentrations.

Ten patients stabilized on racemic methadone dose were switched to R-methadone and effects on serum methadone concentrations were studied. Methadone concentrations (nmol/L) were measured by validated high pressure liquid chromatography coupled to mass spectrometry detection (LC-MSMS).

Time frame: Time frame of each patient form inclusion to end study was 35-40 days.

Effects of switching from racemic methadone to R-methadone on QTc interval

In ten patients QTc intervals were recorded on racemic methadone treatment at Cmin and Cmax of methadone drug concentrations and likewise after the shift to R-methadone. QT intervals (ms) on ECG were recorded automatically and read manually by experienced cardiologists.

Time frame: Time frame of each patient form inclusion to end study was 35-40 days.

Effects of switching from racemic methadone to R-methadone on opioid withdrawal symptoms (OWS)

Ten patients: each patients had OWS recorded on racemic and R-methadone treatment using OWS.

Time frame: Time frame of each patient form inclusion to end study was 35-40 days.

Effects of switching from racemic methadone to R-methadone, stability of serum electrolytes (Ca, Mg, K) in patients

Ten patients: samples for serum electrolytes were collected before and after switch to R-methadone. Measured by routine analysis at Cobas 8000 (unit mmol/L)

Time frame: Time frame of each patient form inclusion to end study was 35-40 days.

Data from ClinicalTrials.gov

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