Methadone-related deaths - epidemiological, pathohistological, and toxicological traits in 10-year retrospective study in Vojvodina, Serbia

Prescribed and Diverted Methadone Toxicity in South Australia: An Update

ABSTRACT

Methadone is one of the most common medications currently prescribed for the treatment of opioid use disorders (OUDs). While methadone maintenance programs (MMPs) have been highly successful in the management and treatment of OUDs resulting in a reduced number of fatalities, the risk of overdose/toxicity remains. The current study was undertaken to analyze trends in overdoses attributed to prescribed and diverted methadone in South Australia (SA) between 2000 and 2019. Over the 20-year period, 344 methadone-related deaths occurred in SA with a significant increase in deaths over the study period ( P = 0.03). The mean age of decedents was 42.5 years with a male to female ratio of 1.8:1, with approximately 20% of decedents enrolled in a MMP at the time of death. Overall, only 5.2% of cases demonstrated methadone diversion, which was associated with methadone prescribed for chronic pain and was most likely to be diverted from a friend/housemate or a partner. However, the source of methadone in more than half of cases was unknown, so this is likely a significant underestimate of actual MMP methadone diversion and total methadone diversion.

The Role of Risk or Contributory Death Factors in Methadone-Related Fatalities: A Review and Pooled Analysis

Methadone-related deaths are characterized by a wide range of post-mortem blood concentrations, due to the high pharmacokinetic/dynamic inter-individual variability, the potential subjective tolerance state and to other risk factors or comorbidities, which might enhance methadone acute toxicity. In the present study, the association among pre-existing and external conditions and diseases and the resultant methadone death capacity have been investigated. Beside a systematic literature review, a retrospective case-control study was done, dividing cases in which methadone was the only cause of death (controls), and those with associated clinical-circumstantial (naive/non-tolerant state), pathological (pulmonary or cardiovascular diseases) or toxicological (other drugs detected) conditions. Methadone concentrations were compared between the two groups and the association with conditions/diseases was assessed by multiple linear and binomial logistic regressions. Literature cases were 139, in house 35, consisting of 22 controls and 152 cases with associated conditions/diseases. Mean methadone concentrations were 2122 ng/mL and 715 ng/mL in controls and cases respectively, with a statistically significant difference (p < 0.05). Lower methadone concentrations (by 24, 19 and 33% respectively) were detected in association with naive/non-tolerant state, pulmonary diseases and presence of other drugs, and low levels of methadone (<600 ng/mL) might lead to death in the presence of the above conditions/diseases.

Quantification of methadone and its metabolites: EDDP and EMDP determined in autopsy cases using LC-MS/MS

The paper presents a method for the determination of methadone, EDDP, and EMDP in postmortem biological materials using liquid-liquid extraction with ethyl acetate (pH9) and UHPLC-MS/MS technique. Methadone-d₉ and EDDP-d₃ were used as the internal standards. The method validation results for blood and urine were as follows: linearity: 0.5-1000 ng/ml; R²  > 0.9993 for methadone, EDDP and R²  > 0.9944 for EMDP. Intra- and inter-day precision: 0.1%-7.5% and 0.3%-8.6%, respectively; intra- and inter-day accuracy: -11.8% to 13.9% and -9.3 to 14.8%, respectively; recovery: 91.5%-123.0%; matrix effect: 83.5%-123.9%. This study also describes 18 postmortem cases, where methadone concentrations ranged 2.3-1180 ng/ml in blood (n = 17), from 11.0 to >10,000 ng/ml in urine (n = 13) and 135.2-409.0 in vitreous humor (VH, n = 3). EDDP concentrations ranged from not detectable to 180 ng/mL in blood, from 42.4 to >10,000 ng/ml in urine and 18.3-36.5 in VH. EMDP concentrations were found in four cases in blood from below LLOQ to 1.8 ng/ml and in seven cases in urine, ranged 2.1-243.0 ng/ml. EMDP was not detected in VH samples. The EDDP/methadone ratios and blood/urine ratios for methadone and EDDP in EMDP-positive and negative cases were performed. The paper presents mass spectra of other methadone metabolites, than EDDP and EMDP (ring hydroxylated methadone, ring hydroxylated EDDP, ring hydroxylated EMDP, methadol, and DDP). Simultaneous determination of methadone and its metabolites in order to unequivocally interpret the results of toxicological tests seems to be useful in cases related to prescription/illicit use of methadone.

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

Methadone has a long history of pain relief and successful substitute for maintenance treatment in heroin and narcotic addiction. The aim of the study was to assess the trends of methadone-associated deaths in Tehran, Iran, in 2009-2015, from a forensic toxicology point of view. All methadone-associated deaths during this 7-year study period were evaluated according to demographic parameters and forensic toxicology analysis results. Results showed that 1274 cases of methadone-associated deaths were investigated during the study period. The incidence rate of methadone-associated deaths had risen 7.7 times in 2015 in comparison with 2009 (p < 0.05). The majority of cases were men (90.35%), aged from 20 to 40 years. About 80% of cases had shown positive results for other drugs and poisons in combination with methadone. Methamphetamine and tramadol were the most drugs detected in post-mortem samples. Death rates among methadone users in Tehran, Iran, increased year by year during 2009-2015. These findings raise the attention to the concomitant use of drugs with the need for changes in regulation and regulatory policy to restrict access and use of controlled drugs.

Cardiovascular effects of methadone and concomitant use of diazepam during methadone maintenance treatment induction: low concentration risk

BACKGROUND

The aim is to evaluate the role of diazepam concentrations in development of low-concentration-methadone-associated QTc prolongation in patients with opioid use disorder during methadone maintenance treatment (MMT) induction.

RESEARCH DESIGN AND METHODS

Individuals with addiction disorder on MMT were studied before the beginning of MMT and after one and six months of MMT. Serum concentrations of methadone, diazepam, electrolytes and ECG were analyzed.

RESULTS

Thirty patients were enrolled. The mean methadone concentration at time points was 177 ± 119 ng/ml and 343 ± 182 ng/ml, while the mean diazepam concentration was 561 ± 437 ng/ml and 1045 ± 933 ng/ml. The QTc interval before the introduction of MMT, after 1 and 6 months of MMT were 412 ± 27 ms, 425 ± 18 ms and 424 ± 15 ms, respectively, showing statistically significant increase in the length of QTc interval after 1 and 6 months of MMT. Statistically significant correlation between the concentration of methadone and QTc interval length at observed time points (R² = 0.239, p = 0.018; R² = 0.513, p = 0.006) was shown, and it remained so if the concentration of diazepam was included (R² = 0.347, p = 0.026, R² = 0.513, p = 0.009).

CONCLUSIONS

The prolongation of QTc below the risk threshold in low methadone therapeutic doses has been recorded and concomitant use of diazepam could be a co-factor in such issue.

Therapeutic and recreational methadone cardiotoxicity

Several classes of drugs have been associated with an increased risk of cardiovascular disease and occurrence of arrhythmias potentially involved in sudden deaths in chronic users even at therapeutic doses. The study presented herein focuses on pathological changes involving the heart possibly due to methadone use. 60 cases were included in the study in total and were divided into three groups (therapeutic methadone users: 20 cases, recreational methadone users: 20 cases, and sudden death group in subjects who had never taken methadone: 20 cases). Autopsies, histology, biochemistry and toxicology were performed in all cases. Macroscopic and microscopic investigation results in therapeutic methadone users were similar to those observed in sudden, unexpected deaths in non-methadone users. In recreational methadone consumers, macroscopic and microscopic examination of the heart failed to provide results consistent with acute or chronic myocardial or coronary damage, thereby corroborating the hypothesis of death most likely following respiratory depression.

Methadone-related deaths. A ten year overview

Over the last 10 years we have registered in our district (about 500,000 inhabitants) 36 cases of fatal methadone poisoning, involving both patients on treatment and naive subjects: this is a significant increase of deaths due to methadone use, misuse or abuse compared with previous years. Twenty-four patients (66.7%) were on methadone maintenance programs for heroin detoxification, while 12 (33.3%) were taking the drug without a medical prescription. The average blood concentration of methadone in patients undergoing a maintenance program was 1.06 mg/L (0.21-3.37 mg/L), against 0.79 mg/L (0.2-3.15 mg/L) in those taking the non-prescribed drug. Since 111 heroin-related deaths were recorded in our district in the same period, the fact that there appear to be many methadone deaths (about a third of heroin-related deaths) cannot be overlooked. The aim of this work is to understand the possible reasons for such a large number of methadone-related deaths. On this subject, we have noticed that risks associated with methadone intake are often underestimated by clinicians prescribing the drug: sometimes methadone is prescribed without taking into account patient's tolerance to opiates, and a large number of subjects enrolled in methadone maintenance programs in Italy, have also been given take-home doses, thus increasing the risk of abuse and diversion.