Methadone substitution: medicolegal problems in Germany

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.

Opioid Use and Driving Performance

INTRODUCTION

The USA is in an opioid epidemic, with an increased number of individuals taking psychoactive drugs while executing the tasks of everyday life, including operating a motor vehicle. The pharmacology of opioids has been widely studied, but the effects of opioids on psychomotor function, driving performance, and the risk of motor vehicle collision remain less clear. Clinicians are faced with the challenge of controlling patient pain while also reconciling conflicting messages from the literature about how safe it is for their patients taking opioids to engage in potentially dangerous routine tasks.

DISCUSSION

This review assesses the current literature regarding opioids as they relate to neurocognitive function, driving performance, and accident risk. Manuscripts are categorized by study context and subject matter: controlled experimental administration, illicit use, prescription use, retrospective forensic toxicology, and polydrug consumption.

CONCLUSION

Illicit use, initiation of therapy, and opioid use in combination with other psychoactive medications are contexts most clearly associated with impairment of driving-related functions and/or operation of a motor vehicle. Clinicians should counsel patients on the risk of impairment when initiating therapy, when co-prescribing opioids and other psychoactive drugs, or when a patient is suspected of having an opioid use disorder.

A possible biomarker for methadone related deaths

Methadone (MTH) concentrations in those dying of MTH toxicity totally overlap concentrations where the presence of MTH is only an incidental finding, making it very difficult to make distinctions in actual cases. A biomarker, be it anatomical or biochemical for MTH toxicity is badly needed, particularly if that markers were known to disrupt effective ventilation. Because the brainstem houses the regulatory centers for cardiorespiratory-control enters, it would seem to be the most likely anatomical site to seek abnormalities in cardiorespiratory control.

OBJECTIVE

To locate and describe the cells of nucleus of the solitary tract (TS)(NTS) in human brainstem and determine if neuronal cell death, either necrotic or apoptotic, within the TS of humans is more common in deaths due directly to MTH toxicity than with in the solitary tract itself.

DESIGN, SETTING, PARTICIPANTS

This was a single cohort study of MTH related decedents autopsied at a large university hospital. Each decedent had a recent history of non medical/illicit MTH use and had been pronounced dead in the field, prior to ever reaching the hospital. Complete autopsy and complete toxicology testing were performed on the formalin fixed brains of each individual. Multiple blocks were prepared of the area of interest, namely the tissue lying immediately between the inferior and the super colliculi. This volume, by definition, would have included the area of the Rostral Ventrolateral Medulla (RVLM), the location of the TS. Immunohistochemistry studies utilizing caspase-9 reaction (a protease enzyme involved in the process of preprogrammed death) were performed in order to estimate the degree and proportion of neuronal apoptosis, and also access the degree of classical necrosis within the NTS.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was the presence or absence of neuronal apoptosis and/or necrosis within the NTS.

RESULTS

Cells displaying evidence of early apoptosis and advanced apoptosis, consisting primarily of nuclear fragmentation, admixed with other neurons displaying the features of classic necrosis were found. Evidence of classic necrosis was identifiable in most of the controls, though minor degrees of apoptosis were identifiable with Caspase staining and quantitative image analysis of immunohistochemical stains.

CONCLUSIONS

and Relevance: Our study shows that neurons, primarily along the TS, but occasionally in other cell nuclei (even controls) are vulnerable, both to direct MTH toxicity (via apoptosis) and indirectly (via hypoxia leading to classical cell necrosis). When MTH is found to be present in significant concentrations, but apoptotic lesions are absent, it would be reasonable to assume that MTH was not primarily the cause of cardiorespiratory arrest.

Characteristics of methadone-related fatalities in Norway

There are currently over 7000 patients enrolled in opioid maintenance treatment (OMT) programs in Norway. A rise in methadone-related deaths proportional to increasing methadone sales over the period 2000-2006 has been observed, but the causative factors for these fatalities have been elusive. In the present study, individual characteristics, methadone concentrations and additional toxicological findings were analyzed. Methadone intoxication deaths (n = 264) were divided into 3 groups according to toxicological findings in whole blood: group 1 - methadone detected alone, or together with one additional drug at low or therapeutic levels, or a low concentration of ethanol (<1 g/L) (n = 21); group 2 - multiple additional drugs/substances detected below lethal levels (n = 175); group 3 - one or more additional drugs/substances detected at lethal levels, or ethanol >3 g/L (n = 55). Methadone blood concentrations in decedents who had been enrolled in OMT were higher than for decedents not in treatment, in all groups. Blood methadone concentrations around 1 mg/L were present in fatal multi-drug intoxications in OMT patients. Results suggest that some patients may be at risk of dying when combining therapeutic concentrations of methadone with other psychoactive substances. Somatic disease was a common finding among deceased OMT patients. Concentrations in methadone users not enrolled in OMT were predominantly between 0.3 and 0.4 mg/L and were not related to the presence of other drugs. However, methadone concentrations below 0.1 mg/L may be associated with intoxication following methadone use, both alone and in combination with other drugs. Younger male users (mean age 34 years) seemed to have a higher susceptibility to methadone intoxication.

Parent and Metabolite Opioid Drug Concentrations in Unintentional Deaths Involving Opioid and Benzodiazepine Combinations

Effects of benzodiazepines on postmortem opioid parent and parent/metabolite blood concentration ratios were determined for fentanyl-, hydrocodone-, methadone-, or oxycodone-related accidental deaths. These opioids are partially metabolized by the CYP3A4 enzyme system, which is also affected by diazepam and alprazolam. Opioid/metabolite combinations examined were as follows: fentanyl/norfentanyl, hydrocodone/dihydrocodeine, methadone/EDDP, and oxycodone/oxymorphone. Parent opioid concentrations were analyzed for 877 deaths. Parent/metabolite concentration ratios were analyzed for 349 deaths, excluding cases with co-intoxicants present known to interfere with opioid elimination. Alprazolam in combination with diazepam significantly decreased median hydrocodone concentrations by 48% (p = 0.01) compared to hydrocodone alone. The methadone parent/metabolite concentration ratio was reduced by 35% in the presence of diazepam compared to methadone alone (p = 0.03). Benzodiazepines did not statistically significantly affect fentanyl or oxycodone concentrations. Possible factors affecting opioid concentrations and possible toxicity development, including any differential effects on specific opioids, should continue to be explored.

Dose-concentration relationships of methadone and EDDP in hair of patients on a methadone-maintenance program

After controlled oral administration of D,L-methadone solution (15-260 mg/day) in the context of a methadone-maintenance program, concentrations of methadone and 2-ethylidine-1,5-dimethyl-3,3-diphenyl-l-pyrrolidine (EDDP), in head hair were determined (N=41), using a fully automated headspace solid-phase microextraction procedure in combination with gas chromatography and mass spectrometry (HS-SPME/GC/MS).Methadone was present in all samples in concentrations ranging from 0.25 to 13.29 ng/mg (mean 2.69±0.45 ng/mg). EDDP was also present in every sample in concentrations ranging from 0.05 to 2.17 ng/mg (mean 0.43±0.08). The concentration ratio methadone/EDDP was 7.5±5.7 in the proximal segments, but decreased to 4.8±1.4 in the distal segments. A statistically significant correlation between the intake dose and the methadone and EDDP concentrations in the subjects' hair could be established only in the proximal segments (r=0.913 for methadone and r=0.901 for EDDP), but not in the distal segments. In all, 131 segments analyzed, the correlation coefficient was r=0.760 for methadone and r=0.738 for EDDP. In comparison to the dose-concentration relationship reported in the literature, we found a better correlation with higher correlation coefficients especially in the proximal segments.However, owing to a broad distribution in the correlation between dosage and concentration, the determination of methadone and EDDP in hair holds only limited information about prior methadone administration.

Comparative risk assessment of alcohol, tobacco, cannabis and other illicit drugs using the margin of exposure approach

A comparative risk assessment of drugs including alcohol and tobacco using the margin of exposure (MOE) approach was conducted. The MOE is defined as ratio between toxicological threshold (benchmark dose) and estimated human intake. Median lethal dose values from animal experiments were used to derive the benchmark dose. The human intake was calculated for individual scenarios and population-based scenarios. The MOE was calculated using probabilistic Monte Carlo simulations. The benchmark dose values ranged from 2 mg/kg bodyweight for heroin to 531 mg/kg bodyweight for alcohol (ethanol). For individual exposure the four substances alcohol, nicotine, cocaine and heroin fall into the "high risk" category with MOE < 10, the rest of the compounds except THC fall into the "risk" category with MOE < 100. On a population scale, only alcohol would fall into the "high risk" category, and cigarette smoking would fall into the "risk" category, while all other agents (opiates, cocaine, amphetamine-type stimulants, ecstasy, and benzodiazepines) had MOEs > 100, and cannabis had a MOE > 10,000. The toxicological MOE approach validates epidemiological and social science-based drug ranking approaches especially in regard to the positions of alcohol and tobacco (high risk) and cannabis (low risk).

Drug-related deaths between 2002 and 2013 with accent to methadone and benzodiazepines

AIM

The aim of the study is to assess the trends of overdose and drug related fatalities in the Republic of Macedonia during the 11 years.

MATERIAL AND METHODS

Cross-sectional retrospective survey and reviewed of postmortem toxicological analyses which examined fatal poisonings with illegal drugs in years 2002-2013. Information about gender, age, drug consumption, reported years were analyzed. Narcotics were confirmed with toxicological semi quantitative fluorescence polarization immunoassay (FPIA) in urine (range 250-4000 ng/ml).

RESULTS

Total of 165 deaths were observed. Out of them 145 (87.9%) were male. There is statistical significant differences between male and female DRD due to age (Mann-Whitney U Test = 925, Z = -2626, p = 0.0087). For p < 0.05 there is significant differences between genders due to cause of overdose (Pearson Chi-square = 9743, df = 4, p = 0.0449). DRD among male were mainly because of overdose due to heroin in 80 (51.17%) cases followed by DRD due to combination of methadone and BZD in 25 (11.72%) cases. Out of all DRD cases 50 (30.3%) are related to polydrug use. For p < 0.01 there is a significant differences between analyzed age groups due to cause of overdose (Pearson Chi-square = 33,886, df = 12, p = 0.0007).

CONCLUSIONS

Death cause analysis reveals the difficulties in determining the role of substitution drugs, as many other factors may be involved. The findings also highlight the importance of further enhancing treatment interventions for benzodiazepine misuse among patients on methadone substitution treatment.

Intravenous methadone application as a serious risk factor for an overdose death: methadone-related fatalities in Hamburg from 2007 to 2012

Methadone plays an increasing role in drug-related deaths in Hamburg. To find out whether intravenous application of methadone plays a relevant role in methadone-related deaths, body fluids of all methadone-positive cases (n=130) and three buprenorphine-positive cases where a urine sample was available (n=58+3) were investigated for disaccharides (sucrose and lactose as markers for intravenous methadone abuse). Sixty-four percent of the urine samples of the methadone cases showed positive results for disaccharides (22 times sucrose alone, range 2 to >1,000 mg/L; 6 times lactose and sucrose; and 9 times lactose alone, range 22 to 382 mg/L). The three buprenorphine cases showed positive results for lactose in urine. In blood, it was not possible to detect any disaccharides. Of the 116 fatal methadone intoxications, 49 % were under opiate maintenance treatment (OMT) at the point of death (A-OMT), 30 % were never in OMT (N-OMT) and 21 % were formerly in an OMT, but not at the point of death (F-OMT). Of the deceased in the OMT group, 12 % (n=7) died within the first 2 weeks of treatment, six of them within the first week. Overall, intravenous abuse of methadone plays a relevant role in methadone-related fatal cases of substituted patients and of drug consumers not in therapy. Thus, it is necessary that therapists keep to the statutory regulations and give take-home doses only after at least 6 months of successful therapy and when there is no suspicion of intravenous abuse.

[Fatal methadone poisoning: observations at the CHU of Liege]

All methadone-associated deaths from October 2002 to April 2005 are analysed. A regular increase in these fatal intoxications has been recorded, in Belgium as in other countries, due, in particular, to an intensified prescription of this product, of which illicit use as street dope becomes problematic. Over the 30 months period covered by the study, 26 deaths related to methadone were listed, of which 3 occurred in accidental circumstances. In the other 23 cases, methadone can be found, yet always associated with psychotropic substances, mainly benzodiazepines (18 cases), narcotics (15 cases) and finally alcohol (5 cases). Based upon the nature of the products combined with methadone, records have been divided in two groups: In the first group (17 observations), xenobiotics at (infra)therapeutic levels are detected. In the other group (6 observations), xenobiotics at high and toxic levels are detected. Blood methadone concentrations are not so different between the 2 groups of individuals since the median values and the extreme values are worth respectively 308, and 110-11300 microg/L, for the first group and 776 and 93-2080 microg/L for the second group. There is thus an important overlap between the therapeutic blood methadone concentrations (150-400 microg/L) and blood concentrations observed in fatalities.Thus, it is necessary that all information and post-mortem results must be examined in a critical way to identify and justify cause of the death.

Methadone-related deaths in Montpellier and Region, from 2000 to 2010

PURPOSE

The objectives of this analysis were to assess the role of methadone and related substances in death occurring, discussing methadone blood concentrations and the contribution of the autopsy to the accountability of methadone in the death process.

METHOD

We retrospectively analyzed all forensic cases positive for methadone from January 2000 to December 2010, in Montpellier and the region served by our laboratory.

RESULTS

During the study period, 64 cases of deaths (11 women, 53 men) with methadone detection were recorded. A progressive increase between 2001 (2 cases) and 2010 (8 cases) was observed. The median age was 33 years old. An autopsy was available in 56.3% of cases. The most frequent finding at the autopsy was non-specific asphyxia death signs (67.6%). Tolerance to opioids was documented in 21 cases. The methadone blood concentrations ranged from 1 to 2 800 ng/mL (59 cases, median value 330 ng/mL). Most of the cases (88%) were polydrug intoxications. The most commonly associated drugs were benzodiazepines (61%), cannabinoids (28%), opioids (19%) and cocaine (12.5%).

CONCLUSION

During a 11-year period, toxicological analyses related to 1991 death cases were performed at the Toxicology Laboratory of Montpellier University Hospital. Of these patients, 64 deaths were possibly related to methadone. Several relevant elements (biological analysis and autopsy) were used to attribute the deaths to the sole methadone (12 cases) or to methadone and associated substances (8 cases).

Neurorobiology and evidence-based biological treatments for substance abuse disorders

Behavioral patterns of addiction include compulsive drug-seeking, persistent abuse of substances despite the often dire consequences on social functioning and physical health, and the high probability of relapse even after prolonged drug-free periods. The recent focus on the biological basis of addiction has provided evidence to support the hypothesis that behavioral manifestations for addiction are influenced by biological factors, and biological factors often produce behavioral changes that can further increase risk. The current understanding of the role of the dopaminergic, glutamatergic, Upsilon-aminobutyric acidergic, and opioid receptor systems in the pathophysiology of addiction as well as the clinical implications of these systems for new and emerging treatments will be discussed. This article will also review the pharmacologic agents used in the treatment of substance abuse disorders and presents evidence-based data for their safety, efficacy, and feasibility of use in different patient populations.

Results of hair analyses for drugs of abuse and comparison with self-reports and urine tests

Urine as well as head and pubic hair samples from drug abusers were analysed for opiates, cocaine and its metabolites, amphetamines, methadone and cannabinoids. Urine immunoassay results and the results of hair tests by means of gas chromatography-mass spectrometry were compared to the self-reported data of the patients in an interview protocol. With regard to the study group, opiate abuse was claimed from the majority in self-reports (89%), followed by cannabinoids (55%), cocaine (38%), and methadone (32%). Except for opiates the comparison between self-reported drug use and urinalysis at admission showed a low correlation. In contrast to urinalysis, hair tests revealed consumption in more cases. There was also a good agreement between self-reports of patients taking part in an official methadone maintenance program and urine test results concerning methadone. However, hair test results demonstrated that methadone abuse in general was under-reported by people who did not participate in a substitution program. Comparing self-reports and the results of hair analyses drug use was dramatically under-reported, especially cocaine. Cocaine hair tests appeared to be highly sensitive and specific in identifying past cocaine use even in settings of negative urine tests. In contrast to cocaine, hair lacks sensitivity as a detection agent for cannabinoids and a proof of cannabis use by means of hair analysis should include the sensitive detection of the metabolite THC carboxylic acid in the lower picogram range.