Risk Factors for Mortality and Endotracheal Intubation after Methadone Intoxication

Abstract

This was a retrospective chart review to evaluate various risk factors associated with in-hospital mortality and intubation risk in acute methadone overdose. All patients admitted to an academic hospital in Tehran, Iran, during a 10-year period (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009) constituted the study sample. Exclusion criteria were significant comorbidities and age under 18 years. Outcome variables were in-hospital mortality and being intubated during admission. A total of 802 patients were enrolled in the study. There were 15 (1.8%) deaths due to methadone overdose or its complications. The number of yearly admissions was 15 patients in 2000, 16 in 2001, 16 in 2002, 18 in 2003, 23 in 2004, 38 in 2005, 59 in 2006, 110 in 2007, 206 in 2008 and 301 in 2009. Based on logistic regression analysis, the most important independent variable predicting mortality was length of admission in toxicology ward [OR (95% CI): 1.6 (1.1-2.3)]. For the prediction of intubation, independent variables were Glasgow Coma Scale (GCS) score of 5-9 [OR (95% CI): 356.5 (9.8-12907.4)] in the emergency department (ED), miosis in the ED [356.9 (1.4-87872.5)] and respiratory rate in the ED [1.5 (1.1-2.1)]. Linear regression model for length of hospitalization showed patient age as the most important variable for prediction of this outcome. Despite a relatively low mortality rate, the increasing number of methadone-poisoned patients requires special attention to this common intoxication. Careful disposition of patients from ED to ordinary wards or intensive care units and also from higher to lower levels of care should be considered in methadone overdose.Methadone, firstly introduced as an opiate substitution therapy agent in 1965, was described by Dole and Nyswander for methadone maintenance treatment (MMT) in rehabilitation programmes for heroin addicts [1,2]. Since that time, especially from the 1990s, methadone has been implicated in many overdose deaths and admissions to hospital emergency departments (EDs) because of its potential for abuse [3,4].Overdosing with methadone is a growing healthcare problem in many countries as a result of the widespread opioid abstinence programmes and increased availability of this drug. Death or any other adverse outcome from methadone poisoning are potentially preventable because of the long-term nature of clinical sequelae [5]. The majority of deaths due to illicit drug use were found to be related to accidental poisoning; methadone and heroin/morphine were responsible for about two-thirds of these deaths [6]. In heroin-addicted patients under MMT, one study found methadone overdose as the third cause of mortality following accidents and suicide [7].Studies have shown the correlation of some factors with mortality in methadone-prescribed patients; these include prescription of methadone for chronic pain, higher doses of methadone prescribed, sleep apnoea, psychiatric admission, history of benzodiazepines or barbiturates consumption, first 2 weeks of therapy and correct...

Forensic Toxicology Perspectives of Methadone‐associated Deaths in Tehran, Iran, a 7‐year Overview

“…Methadone affects the electrical conductivity of the heart muscle specifically shown as prolongation of QT interval [37,38]. This phenomenon can cause sudden cardiac death [38]. Methamphetamine was detected in 291 (22.84%) of cases, and also, cocaine was detected in post-mortem samples of one case confirmed by GC/MS instrumentation.…”

“…There is increasing recognition of the importance of increased cardiovascular disease and the presence of arrhythmias in sudden deaths due to methadone use . Methadone affects the electrical conductivity of the heart muscle specifically shown as prolongation of QT interval . This phenomenon can cause sudden cardiac death .…”

Suspected Methadone Toxicity: from Hospital to Autopsy Bed

“…Methadone use/abuse has significantly increased during recent years resulting in higher sensitivity of medical staff to methadone toxicity . In fact, considering miotic pupils in opioid‐dependent patients arriving in comatose state, medical staff may falsely assume that the patient is methadone‐intoxicated and treat him/her as a poisoned patient while the main background disease making the patient refer to the healthcare facility may be completely irrelevant to methadone intoxication.…”

“…The retrospective nature of the study and lack of documentation of some variables were other major limitations. We did not study the electrocardiogram to see possible changes in the QT interval that might influence the reported outcome, either .…”

Developing a novel prediction model in opioid overdose using machine learning; a pilot analytical study

“…Also, severe loss of consciousness and acute renal dysfunction were determined to be poor prognostic factors. 31 , 34 …”