London audit of drug-related overdose deaths: characteristics and typology, and implications for prevention and monitoring

An evaluation of naloxone transit for opioid overdose using drones: A case study using real-world coroner data

BACKGROUND AND AIMS

Opioids are now the most cited class in fatal overdoses. However, the antidote for opioid overdose-naloxone-is not always readily available. Our aim was to evaluate the feasibility of naloxone transit via drone to provide rapid access at the point of care.

METHODS AND FINDINGS

Real-world data pertaining to opioid overdoses, which occurred in the Teesside area of the UK 2015-2019, were extracted from the National Programme on Substance Abuse Deaths (NPSAD). The original locations of these opioid overdoses were used to compare the projected response times of ambulances with that of drones when considering the impacts of actual traffic and weather conditions, respectively; 58 cases were identified where a bystander-who could have called for and administered emergency naloxone-was likely present.

RESULTS

In 78% of cases (n = 45/58) a class C1 commercial-off-the-shelf drone carrying naloxone could have reached the overdose location in 7 min-the benchmark time for the arrival of emergency services for Category 1 calls in England. With the implementation of recent advances in drone engineering, such as increased speeds and temperature-controlled cargo cradles, it is estimated that 98% of overdoses could have been reached in this timeframe (n = 57/58). Ambulances were able to reach a significantly lower number of cases in 7 min, even when considering best-case scenario traffic conditions (14%, n = 8/58, χ2 P < 0.001).

CONCLUSIONS

This study provides proof-of-concept that, in the Teesside area of the UK, drones are more likely than ambulance to get naloxone to the site of an opioid overdose in 7 min.

Trends in deaths following drug use in England before, during, and after the COVID-19 lockdowns

Aim

This research aimed to describe how the characteristics of deaths following drug use changed during the COVID-19 pandemic in England, and how this can inform future strategy to support the health and social care of people who use drugs in future emergency scenarios.

Method

All deaths reported to the National Programme on Substance Abuse Deaths which occurred between January 2018 and December 2021 inclusive were extracted for analysis. Exponential smoothing models were constructed to determine any differences between forecasted vs. actual trends.

Key results

Following the first lockdown period in England there were significant increases in the proportion of people who died at home beyond the 95% confidence bounds of the exponential smoothing model and concurrent decreases in the proportion of people who died in hospital. Whilst the overall proportion of deaths attributable to opioids did not significantly deviate from the forecasted trend, there were significant increases in methadone-related deaths and decreases in heroin/morphine-related death beyond the 95% confidence bounds. The proportion of deaths concluded as suicide increased, as did those implicating antidepressant use. There were no changes in the proportion of deaths following use of other drug classes, alcohol use in combination with psychoactive drugs, or on decedent demographics (gender, age, and drug user status). A small number of deaths due to drug use had COVID-19 infection itself listed as a cause of death (n = 23).

Conclusion

For people who use drugs, the impact of the restrictions due to the COVID-19 pandemic was greater than that of infection from the virus itself. The health and social care strategy for these people needs to be pre-emptively adapted to mitigate against the specific risk factors for fatal drug overdose associated with future emergency scenarios.

Synthetic Cannabinoid-Related Deaths in England, 2012-2019

Aim: To identify drug-related death trends associated with synthetic cannabinoid receptor agonists (SCRAs) reported to the National Programme on Substance Abuse Deaths (NPSAD) from England. Design: Case reports from NPSAD (England) where a SCRA was detected in post-mortem tissue(s) and/or implicated in the death were extracted, analyzed, and compared against non-SCRA-related deaths that occurred over the same time period (2012-2019). Findings: One hundred sixty-five death SCRA-related reports were extracted, with 18 different SCRAs detected. Following the first death in 2012, a subsequent sharp increase in reporting is evident. Acute SCRA use was the underlying cause of death in the majority of cases (75.8%) with cardiorespiratory complications the most frequently cited underlying physiological cause (13.4%). SCRA users were predominantly found dead (68.6%), with a large proportion of those witnessed becoming unresponsive described as suddenly collapsing (81.6%). Psychoactive polydrug use was detected in 90.3% of cases, with alcohol the most commonly co-detected (50.3%), followed by opioids (42.2%), benzodiazepines/Z-drugs (32.1%), stimulants (32.1%, [28.5% cocaine]), and cannabis (24.8%). Compared to all non-SCRA-related NPSAD deaths occurring over the same time period, SCRA-related decedents were more predominantly male (90.3% vs. 72.0%; p<0.01), and lived in more deprived areas (p<0.01). While a comparatively significant proportion of decedents were homeless (19.4% vs. 4.1%), living in a hostel (13.3% vs. 2.3%) or in prison (4.9% vs. 0.2%) at time of death (all p<0.01), the greatest majority of SCRA-related decedents were living in private residential accommodations (57.6%). Conclusions: This is the largest dataset regarding SCRA-related mortalities reported to date. Reporting of SCRA-related deaths in England have increased considerably, with polydrug use a specific concern. Lack of effective deterrents to SCRA use under current UK legislation, compounded by limited knowledge regarding the physiological impacts of SCRA consumption and their interaction with other co-administered substances are contributory factors to the occurrence of SCRA-related mortalities in an increasingly deprived demographic.

Petechial hemorrhages, ethanol, and opioids in victims from intoxication

Petechial hemorrhages are of interest to forensic pathologists because of their association with pressure on the neck. This study shows the associations between ethanol, opioids in blood and the risk of petechiae in conjunctivae and eye lids of 865 medico-legally examined victims from intoxication, 112 (12.9 %) with petechiae. Livor mortis on the front, face down body position, higher body weight, and younger age of the victims were independently associated with higher risk of petechiae. These variables were used for adjustment in the logistic regression analyzes. We found associations between ethanol, opioids, and the risk of petechiae when analyzed simultaneously. The association between ethanol and the risk of petechiae differed in opioid negative and positive victims (interaction, p = 0.028). In the opioid negative group, the association was J-formed, victims with low to medium level ethanol having lower risk (OR = 0.77) than those without ethanol or opioids, whereas high ethanol level gave a 4-fold higher risk (OR = 3.97). In the opioid positive group, the J-formed pattern was reversed. Victims with low to medium level ethanol had more than 4 times higher risk (OR = 4.65), whereas high level ethanol gave a slightly elevated risk (OR = 1.34) only compared to no ethanol or opioids. The results suggest that ethanol and opioids have a complex association with the risk of petechiae independent of livor mortis, initial body position, body weight, and age in victims from intoxication. Of practical value for the post-mortem examination is that the pathologist must consider both the ethanol level and the presence of opioids when judging the significance of petechiae in the eye regions.

Role of Acetaldehyde in Ethanol Reversal of Tolerance to Morphine-Induced Respiratory Depression in Mice

Background: Opioid users regularly consume other drugs such as alcohol (ethanol). Acute administration of ethanol rapidly reverses tolerance to morphine-induced respiratory depression. However, recent research has suggested that the primary metabolite of ethanol, acetaldehyde, may play a key role in mediating the CNS effects seen after ethanol consumption. This research investigated the role of acetaldehyde in ethanol reversal of tolerance to morphine-induced respiratory depression.

Methods: Tolerance was induced in mice by 6-days implantation of a 75 mg morphine pellet with control mice implanted with a placebo pellet. Tolerance was assessed by acute morphine administration on day 6 and respiration measured by plethysmography. Levels of acetaldehyde were inhibited or enhanced by pre-treatments with the acetaldehyde chelator D-penicillamine and the inhibitor of acetaldehyde dehydrogenase disulfiram respectively.

Results: Morphine pellet implanted mice displayed tolerance to an acute dose of morphine compared to placebo pellet implanted controls. Acute acetaldehyde administration dose-dependently reversed tolerance to morphine respiratory depression. As previously demonstrated, ethanol reversed morphine tolerance, and this was inhibited by D-penicillamine pre-treatment. An acute, low dose of ethanol that did not significantly reverse morphine tolerance was able to do so following disulfiram pre-treatment.

Conclusion: These data suggest that acetaldehyde, the primary metabolite of ethanol, is responsible for the reversal of morphine tolerance observed following ethanol administration.

Antihistamine-related deaths in England: Are the high safety profiles of antihistamines leading to their unsafe use?

AIMS

Antihistamines are routinely taken to control allergic reactions or sedation to induce sleep. There are, however, growing concerns regarding sedating antihistamine misuse. This research aims to evaluate deaths related to antihistamines in England occurring during 2000-2019.

METHODS

Cases reported to the National Programme on Substance Abuse Deaths from England occurring in 2000-2019 with antihistamine detections at postmortem were extracted for analysis.

RESULTS

In total, 1666 antihistamine postmortem detections were identified from 1537 cases. Sedating antihistamines available for purchase under pharmacist supervision but without need for a prescription (pharmacy-only medications) were present in a significant majority of cases (85.2%, P < .01). Despite an increasing trend for antihistamine-related deaths over time, the proportion of deaths where an antihistamine was implicated declined over the same period. Specific concerns with regards to the misuse of these pharmacy-only sedating antihistamines are raised with regards to the significant proportion of cases that were concluded as suicide (20.9%, P < .01), and the high prevalence of their use in combination with other central nervous system depressants (94.8% of cases).

CONCLUSION

This is the first report in over 40 years regarding antihistamine-related mortality from England. The rising trend in sedating antihistamine-related deaths may be contributed to by their increasing availability and the perceived negligible dangers associated with antihistamines, both from the general public and learned professionals. Awareness of the dangerous sedative properties that some antihistamines possess is, however, heightened in individuals deliberately seeking these effects. Urgent review of sedating antihistamines currently assigned under the pharmacy-only classification is needed to achieve antihistamine harm reduction.

Past 12-month nonfatal overdose among people who inject drugs in Ukraine: City-level estimates and risk factors from a cross-sectional study

BACKGROUND

Nonfatal overdose contributes to high morbidity and is among the strongest proxies for the occurrence of overdose fatality - the leading cause of death among those who use opioids. In Ukraine, a majority of people who inject drugs (PWID) use opioids, but little is known about the relationship between drug market characteristics, nonfatal overdose (NFOD) prevalence, and risk factors for NFOD.

METHODS

We used cross-sectional respondent-driven sampling (RDS) data to explore the variability of recent (past 12 months) NFOD among PWID across Ukrainian cities and associations with individual factors. The population-averaged -cross-sectional associations were estimated and compared using generalized linear models for the binary outcome (NFOD vs. not) with robust variance estimates.

RESULTS

Recent self-reported NFOD varied between 1% and 14 % across Ukrainian cities. In adjusted analyses, overdose was associated with fewer years of injecting drugs; a higher number of types of drugs used in the past 12 months; using desomorphine, methadone, tramadol, heroin, amphetamine-type drugs or cocaine within past 12 months; using alcohol daily or weekly; recent drug treatment; and history of incarceration. Buying drugs or their ingredients through "stashes" (i.e., drugs secretly hidden in various places) and the perception of drug price increase were associated with higher odds of reporting NFOD.

CONCLUSION

The identified risk factors underscore the importance of evidence-based prevention efforts, such as scaling-up opioid agonist therapy, providing naloxone in the community and upon prison release, targeting those most likely to witness overdose and sharing overdose prevention strategies with them, and continuous monitoring of trends and contributing factors.

The importance of sample size with regard to the robustness of postmortem reference values

Evaluating postmortem toxicological results is a challenging task due to multiple factors affecting blood concentrations after death. In order to improve the diagnostic accuracy in cases of suspected fatal intoxication different compilations of postmortem reference drug concentrations are often used. However, it is not clear what constitutes a reliable postmortem reference value. The current study presents reference concentrations for 13 substances from seven substance groups according to a standardized protocol. The reference concentrations were gathered from 3767 autopsy cases and subdivided into intoxications by one substance only (Group A, n=611), multi-substance intoxications (Group B, n=1355) and postmortem controls, in which incapacitation by drugs were excluded (Group C, n=1801). In particular, this study presents statistical information about the precision and conformity change with various sample sizes. Based on the present data >10 detections are usually needed, for the substances examined, to differentiate between intoxication cases and controls. Repeated samplings show that the median of small samples (N=≤5) has a high variation (normalized interquartile range 138-75%) and that a high number of detections (N=>20) in each group are needed to reduce the variation.

Dihydrocodeine for detoxification and maintenance treatment in individuals with opiate use disorders

BACKGROUND

Medical treatment and detoxification from opiate disorders includes oral administration of opioid agonists. Dihydrocodeine (DHC) substitution treatment is typically low threshold and therefore has the capacity to reach wider groups of opiate users. Decisions to prescribe DHC to patients with less severe opiate disorders centre on its perceived safety, reduced toxicity, shorter half-life and more rapid onset of action, and potential retention of patients. This review set out to investigate the effects of DHC in comparison to other pharmaceutical opioids and placebos in the detoxification and substitution of individuals with opiate use disorders.

OBJECTIVES

To investigate the effectiveness of DHC in reducing illicit opiate use and other health-related outcomes among adults compared to other drugs or placebos used for detoxification or substitution therapy.

SEARCH METHODS

In February 2019 we searched Cochrane Drugs and Alcohol's Specialised Register, CENTRAL, PubMed, Embase and Web of Science. We also searched for ongoing and unpublished studies via ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and Trialsjournal.com. All searches included non-English language literature. We handsearched references of topic-related systematic reviews and the included studies.

SELECTION CRITERIA

We included randomised controlled trials that evaluated the effect of DHC for detoxification and maintenance substitution therapy for adolescent (aged 15 years and older) and adult illicit opiate users. The primary outcomes were abstinence from illicit opiate use following detoxification or maintenance therapy measured by self-report or urinalysis. The secondary outcomes were treatment retention and other health and behaviour outcomes.

DATA COLLECTION AND ANALYSIS

We followed the standard methodological procedures that are outlined by Cochrane. This includes the GRADE approach to appraise the quality of evidence.

MAIN RESULTS

We included three trials (in five articles) with 385 opiate-using participants that measured outcomes at different follow-up periods in this review. Two studies with 150 individuals compared DHC with buprenorphine for detoxification, and one study with 235 participants compared DHC to methadone for maintenance substitution therapy. We downgraded the quality of evidence mainly due to risk of bias and imprecision. For the two studies that compared DHC to buprenorphine, we found low-quality evidence of no significant difference between DHC and buprenorphine for detoxification at six-month follow-up (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.25 to 1.39; P = 0.23) in the meta-analysis for the primary outcome of abstinence from illicit opiates. Similarly, low-quality evidence indicated no difference for treatment retention (RR 1.29, 95% CI 0.99 to 1.68; P = 0.06). In the single trial that compared DHC to methadone for maintenance substitution therapy, the evidence was also of low quality, and there may be no difference in effects between DHC and methadone for reported abstinence from illicit opiates (mean difference (MD) -0.01, 95% CI -0.31 to 0.29). For treatment retention at six months' follow-up in this single trial, the RR calculated with an intention-to-treat analysis also indicated that there may be no difference between DHC and methadone (RR 1.04, 95% CI 0.94 to 1.16). The studies that compared DHC to buprenorphine reported no serious adverse events, while the DHC versus methadone study reported one death due to methadone overdose.

AUTHORS' CONCLUSIONS

We found low-quality evidence that DHC may be no more effective than other commonly used pharmacological interventions in reducing illicit opiate use. It is therefore premature to make any conclusive statements about the effectiveness of DHC, and it is suggested that further high-quality studies are conducted, especially in low- to middle-income countries.

Investigating opioid-related fatalities in southern Sweden: contact with care-providing authorities and comparison of substances

Background

Opioid-related deaths have increased in Western countries over recent decades. Despite numerous studies investigating opioid-related mortality, only a few have focused on the lives of the deceased individuals prior to their deaths, specifically regarding contact with care-providing authorities such as health, social and correctional services. Furthermore, a change has been noted in the last two decades as to which opioids cause most deaths, from heroin to prescription opioids. However, studies comparing fatalities caused by different substances are rare. The aim of this study was to investigate contact with care-providing authorities during the year prior to death among individuals who died as a result of opioid intoxication and to analyse differences relating to which opioids caused their deaths.

Methods

The study is based on retrospective register data and includes 180 individuals with a history of illicit drug use, who died from opioid intoxication in Skåne, Sweden, between 1 January 2012 to 31 December 2013 and 1 July 2014 to 30 June 2016. Intoxications caused by heroin, methadone, buprenorphine and fentanyl were included. Data were collected from the National Board of Forensic Medicine, regional health care services, municipal social services and the Prison and Probation Service. Statistical testing was performed using Pearson’s chi-square test, Fisher’s exact test and the Mann-Whitney U test to analyse group differences.

Results

A total of 89% of the deceased individuals had been in contact with one or more of the care-providing authorities during the year prior to death; 75% had been in contact with health care, 69% with the social services, 28% with the Prison and Probation Service, and 23% had been enrolled in opioid substitution treatment at some point during their final year of life. Few differences appeared between the substance groups with regard to which opioid contributed to the death. In addition to opioids, sedatives were present in more than 80% of the cases. Individuals whose deaths were buprenorphine-related had been in contact with the social services to a significantly lesser extent during the year prior to death.

Conclusions

The studied population is characterised by extensive contact with care-providing authorities, thus providing numerous opportunities for authorities to reach this group with preventive and other interventions. Few differences emerged between groups with regard to which opioid had contributed to the death.

Prolonged ethanol administration prevents the development of tolerance to morphine-induced respiratory depression

BACKGROUND

Opioid users regularly consume other drugs such as alcohol (ethanol). Acute administration of ethanol can rapidly reverse tolerance to morphine-induced respiratory depression. However, alcohol consumption by opioid users is likely to occur over prolonged time periods. We have therefore sought to determine the effect of prolonged alcohol consumption on the development of tolerance to opioid respiratory depression.

METHODS

Mice were fed control or ethanol (5%) liquid diet for 16 days. On days 9-16 morphine tolerance was induced by administration of 3 priming injections of morphine followed by subcutaneous implantation of a morphine-filled osmotic mini-pump. Control mice received saline. Respiration was measured by plethysmography and the effect of an acute morphine challenge dose was measured on day 16 to assess the development of morphine tolerance.

RESULTS

Prolonged ethanol consumption for 14 days did not alter the respiratory depressant effect of an acute dose of morphine. Control mice treated with prolonged morphine developed tolerance to acute morphine respiratory depression whereas ethanol diet fed mice treated with prolonged morphine showed significant respiratory depression during morphine-pump treatment and remained sensitive to the respiratory depressant effect of the acute challenge dose of morphine. The ethanol consumption did not alter blood or brain levels of morphine, whilst conversely prolonged morphine treatment did not alter blood levels of ethanol.

CONCLUSIONS

Prolonged ethanol consumption prevents the development and maintenance of tolerance to the respiratory depressant effect of morphine. These data suggest that ethanol inhibition of tolerance will greatly increase the risk of fatal heroin overdose in humans.

Oxycodone-induced tolerance to respiratory depression: reversal by ethanol, pregabalin and protein kinase C inhibition

BACKGROUND AND PURPOSE

Oxycodone, a prescription opioid, is a major drug of abuse, especially in the USA, and contributes significantly to opioid overdose deaths each year. Overdose deaths result primarily from respiratory depression. We have studied respiratory depression by oxycodone and have characterized how tolerance develops on prolonged exposure to the drug. We have investigated the role of PKC in maintaining tolerance and have examined whether ethanol or pregabalin reverses oxycodone-induced tolerance.

EXPERIMENTAL APPROACH

Respiration was measured in male CD-1 mice by whole-body plethysmography. Mice were preinjected with oxycodone then implanted with mini-pumps (s.c.) delivering 20, 45 or 120 mg·kg-1 ·day-1 oxycodone for 6 days and subsequently challenged with oxycodone (3 mg·kg-1 , i.p.) or morphine (10 mg·kg-1 , i.p.) to assess the level of tolerance.

KEY RESULTS

Oxycodone-treated mice developed tolerance to oxycodone and cross tolerance to morphine-induced respiratory depression. Tolerance was less with 20 mg·kg-1 ·day-1 than with 45 or 120 mg·kg-1 ·day-1 oxycodone treatment. At doses that do not depress respiration, ethanol (0.3 g·kg-1 ), pregabalin (20 mg·kg-1 ) and calphostin C (45 μg·kg-1 ) all reversed oxycodone-induced tolerance resulting in significant respiratory depression. Reversal of tolerance was less in mice treated with oxycodone (120 mg·kg-1 ·day-1 ). In mice receiving ethanol and calphostin C or ethanol and pregabalin, there was no greater reversal of tolerance than seen with either drug alone.

CONCLUSION AND IMPLICATIONS

These data suggest that oxycodone-induced tolerance is mediated by PKC and that reversal of tolerance by ethanol or pregabalin may be a contributory factor in oxycodone overdose deaths.

Risk to heroin users of polydrug use of pregabalin or gabapentin

AIM

To examine the risk to heroin users of also using gabapentin or pregabalin (gabapentoids).

DESIGN

Multi-disciplinary study: we (a) examined trends in drug-related deaths and gabapentoid prescription data in England and Wales to test for evidence that any increase in deaths mentioning gabapentin or pregabalin is associated with trends in gabapentoid prescribing and is concomitant with opioid use; (b) interviewed people with a history of heroin use about their polydrug use involving gabapentin and pregabalin; and (c) studied the respiratory depressant effects of pregabalin in the absence and presence of morphine in mice to determine whether concomitant exposure increased the degree of respiratory depression observed.

SETTING

England and Wales.

PARTICIPANTS

Interviews were conducted with 30 participants (19 males, 11 female).

MEASUREMENTS

(a) Office of National Statistics drug-related deaths from 1 January 2004 to 31 December 2015 that mention both an opioid and pregabalin or gabapentin; (b) subjective views on the availability, use, interactions and effects of polydrug use involving pregabalin and gabapentin; and (c) rate and depth of respiration.

RESULTS

Pregabalin and gabapentin prescriptions increased approximately 24% per year from 1 million in 2004 to 10.5 million in 2015. The number of deaths involving gabapentoids increased from fewer than one per year prior to 2009 to 137 in 2015; 79% of these deaths also involved opioids. The increase in deaths was correlated highly with the increase in prescribing (correlation coefficient 0.94; 5% increase in deaths per 100 000 increase in prescriptions). Heroin users described pregabalin as easy to obtain. They suggested that the combination of heroin and pregabalin reinforced the effects of heroin but were concerned it induced 'blackouts' and increased the risk of overdose. In mice, a low dose of S-pregabalin (20 mg/kg) that did not itself depress respiration reversed tolerance to morphine depression of respiration (resulting in 35% depression of respiration, P < 0.05), whereas a high dose of S-pregabalin (200 mg/kg) alone depressed respiration and this effect summated with that of morphine.

CONCLUSIONS

For heroin users, the combination of opioids with gabapentin or pregabalin potentially increases the risk of acute overdose death through either reversal of tolerance or an additive effect of the drugs to depress respiration.

The extent of and factors associated with self-reported overdose and self-reported receipt of naloxone among people who inject drugs (PWID) in England, Wales and Northern Ireland

BACKGROUND

Overdose is a major cause of death among PWID, and for opioid overdoses naloxone administration can reduce harm. However, globally there is limited national level data on the extent of non-fatal overdose and naloxone uptake. The first national level data on the extent of self-reported overdose and self-reported receipt of naloxone among UK PWID, providing a baseline to monitor the impact of the recent policy change regarding naloxone availability, is presented.

METHODS

Data on self-reported overdose and receipt of naloxone during the preceding year for 2013-2014 from a national survey of PWID was analysed. Participants who reported injecting during the preceding year were included.

RESULTS

Participants (3850) were predominantly male (75%); mean age was 36 years. The most commonly injected drugs were: heroin (91%), crack (45%) and amphetamine (29%). 15% (591) reported overdosing during the preceding year. There were no differences in the proportion reporting overdose by age or gender, but overdose was more common among those who: injected multiple drugs; recently ceased addiction treatment; injected with used needles/syringes; ever had transactional sex; had used a sexual health clinic or emergency department and lived in Wales or Northern Ireland. Among those reporting an overdose during the preceding year, a third reported two to four overdoses and 7.5% five or more overdoses; half reported receiving naloxone. Those reporting naloxone receipt in the preceding year were more likely to: live in Wales or Northern Ireland; ever received used needles/syringes; ever been imprisoned; and less likely to have injected two drug types.

CONCLUSION

These data provide a baseline for monitoring the impact of the 2015 UK policy change to improve take-home naloxone access. Interventions tackling overdose should promote naloxone awareness and access, and target those who; are poly-drug injectors, have ceased treatment, share needles/syringes and whose drug use links to sexual activity.

Development of a proto-typology of opiate overdose onset

BACKGROUND AND AIMS

The time available to act is a crucial factor affecting the probable success of interventions to manage opiate overdose. We analyse opiate users' accounts of non-fatal overdose incidents to (i) construct a proto-typology of non-fatal opiate overdose onset and (ii) assess the implications for overdose management and prevention of fatalities.

METHODS

Re-analysis of a subset of data from a large qualitative study of non-fatal opiate overdose conducted from 1997 to 1999. Data were generated from semi-structured interviews undertaken with opiate users who had experienced a non-fatal overdose in the previous 24 hours. Forty-four participants (30 men; 14 women; aged 16-47 years) provided sufficient information for in-depth analysis. Data relating to 'memory of the moment of overdose', 'time to loss of consciousness' and 'subjective description of the overdose experience' were scrutinised using iterative categorization.

FINDINGS

Four types of overdose onset were identified: type A 'amnesic' (n = 8), characterized by no memory, rapid loss of consciousness and no description of the overdose experience; type B 'conscious' (n = 17), characterized by some memory, sustained consciousness and a description of the overdose in terms of feeling unwell and symptomatic; type C 'instant' (n = 14), characterized by some memory, immediate loss of consciousness and no description of the overdose experience; and type D 'enjoyable' (n = 5), characterized by some memory, rapid loss of consciousness and a description of the overdose experience as pleasant or positive.

CONCLUSIONS

The identification of different types of overdose onset highlights the complexity of overdose events, the need for a range of interventions and the challenges faced in managing incidents and preventing fatalities. Opiate overdose victims who retain consciousness for a sustained period and recognize the negative signs and symptoms of overdosing could summon help or self-administer naloxone, thus indicating that opiate overdose training should incorporate self-management strategies.

Nonmedical use of prescription drugs in the European Union

BACKGROUND

Nonmedical prescription drug use (NMPDU) refers to the self-treatment of a medical condition using medication without a prescriber's authorization as well as use to achieve euphoric states. This article reports data from a cross-national investigation of NMPDU in five European Countries, with the aim to understand the prevalence and characteristics of those engaging in NMPDU across the EU.

METHODS

A parallel series of self-administered, cross-sectional, general population surveys were conducted in 2014. Data were collected using multi-stage quota sampling and then weighted using General Exponential Model. A total of 22,070 non-institutionalized participants, aged 12 to 49 years, in 5 countries: Denmark, Germany, Great Britain, Spain, and Sweden. Lifetime and past-year nonmedical use of prescription medications such as stimulants, opioids, and sedatives were ascertained via a modified version of the World Health Organization's Composite International Diagnostic Interview. Information about how the medications were acquired for NMPDU were also collected from the respondent.

RESULTS

Lifetime and past-year prevalence of nonmedical prescription drug use was estimated for opioids (13.5 and 5.0 %), sedatives (10.9 and 5.8 %), and stimulants (7.0 and 2.8 %). Germany exhibited the lowest levels of NMPDU, with Great Britain, Spain, and Sweden having the highest levels. Mental and sexual health risk factors were associated with an increased likelihood of past-year nonmedical prescription drug use. Among past-year users, about 32, 28, and 52 % of opioid, sedative, and stimulant nonmedical users, respectively, also consumed illicit drugs. Social sources (sharing by friends/family) were the most commonly endorsed methods of acquisition, ranging from 44 % (opioids) to 62 % (sedatives). Of interest is that Internet pharmacies were a common source of medications for opioids (4.1 %), stimulants (7.6 %), and sedatives (2.7 %).

CONCLUSIONS

Nonmedical prescription drug use was reported across the five EU countries we studied, with opioids and sedatives being the most prevalent classes of prescription psychotherapeutics. International collaborations are needed for continued monitoring and intervention efforts to target population subgroups at greatest risk for NMDU.

Ethanol Reversal of Tolerance to the Respiratory Depressant Effects of Morphine

Opioids are the most common drugs associated with unintentional drug overdose. Death results from respiratory depression. Prolonged use of opioids results in the development of tolerance but the degree of tolerance is thought to vary between different effects of the drugs. Many opioid addicts regularly consume alcohol (ethanol), and post-mortem analyses of opioid overdose deaths have revealed an inverse correlation between blood morphine and ethanol levels. In the present study, we determined whether ethanol reduced tolerance to the respiratory depressant effects of opioids. Mice were treated with opioids (morphine, methadone, or buprenorphine) for up to 6 days. Respiration was measured in freely moving animals breathing 5% CO2 in air in plethysmograph chambers. Antinociception (analgesia) was measured as the latency to remove the tail from a thermal stimulus. Opioid tolerance was assessed by measuring the response to a challenge dose of morphine (10 mg/kg i.p.). Tolerance developed to the respiratory depressant effect of morphine but at a slower rate than tolerance to its antinociceptive effect. A low dose of ethanol (0.3 mg/kg) alone did not depress respiration but in prolonged morphine-treated animals respiratory depression was observed when ethanol was co-administered with the morphine challenge. Ethanol did not alter the brain levels of morphine. In contrast, in methadone- or buprenorphine-treated animals no respiratory depression was observed when ethanol was co-administered along with the morphine challenge. As heroin is converted to morphine in man, selective reversal of morphine tolerance by ethanol may be a contributory factor in heroin overdose deaths.

The relative risk of fatal poisoning by methadone or buprenorphine within the wider population of England and Wales

OBJECTIVE

To examine the population-wide overdose risk emerging from the prescription of methadone and buprenorphine for opioid substitution treatment in England and Wales.

DESIGN

Retrospective administrative data study.

SETTING

National databases for England and Wales.

PARTICIPANTS/CASES

Drug-related mortality data were drawn from the Office for National Statistics, and prescription data for methadone and buprenorphine were obtained from the National Health Service for the years 2007-2012. During this 6-year period, a total of 2366 methadone-related deaths and 52 buprenorphine-related deaths were registered, corresponding to 17,333,163 methadone and 2,602,374 buprenorphine prescriptions issued. The analysis encompassed poisoning deaths among members of the wider population of England and Wales who consumed, but were not prescribed these medications, in addition to patients prescribed methadone or buprenorphine.

MAIN OUTCOME MEASURES

Mortality risk: substance-specific overdose rate per 1000 prescriptions issued; relative risk ratio of methadone in relation to buprenorphine.

RESULTS

During the years 2007-2012, the pooled overdose death rate was 0.137/1000 prescriptions of methadone, compared to 0.022/1000 prescriptions of buprenorphine (including buprenorphine-naloxone). The analysis generated a relative risk ratio of 6.23 (95% CI 4.79 to 8.10) of methadone in relation to buprenorphine. UK Borders Agency data were taken into consideration and revealed that only negligible amounts of methadone and buprenorphine were seized on entering UK territory between 2007 and 2012, suggesting domestic diversion.

CONCLUSIONS

Our analysis of the relative safety of buprenorphine and methadone for opioid substitution treatment reveals that buprenorphine is six times safer than methadone with regard to overdose risk among the general population. Clinicians should be aware of the increased risk of prescribing methadone, and tighter regulations are needed to prevent its diversion.

Drug-related causes of death: Socioeconomic and demographic characteristics of the deceased

AIM

The aim of this study was to describe subgroups of those who died from a drug-related cause of death employing demographic and socioeconomic data.

METHODS

A total of 1,628 persons with registered drug-related deaths in the Norwegian Cause of Death Registry between 2003 and 2009 were matched with research registers of data on demographic and socioeconomic factors during the five years prior to their deaths.

RESULTS

Three equal-sized clusters were identified: persons with very low socioeconomic status, disability pensioners and people on the edge of the workforce.

CONCLUSIONS

Socioeconomic situation prior to drug-related deaths was more heterogeneous than expected. Greater knowledge about the members of the disability pensioner and the edge of the workforce clusters must be established in order to make prevention efforts towards these groups more precise and goal oriented.

The message of the heroin overdoses

Drug use can be defined as a kind of self destruction, and it is directly linked to attitudes toward death and suicide occurring in a significant number of users of different narcotics. The aim of the authors was to look for the background of this relationship between drug and death and examine the origin, development, and motives behind heroin overdose based on an analysis of previous studies. It seems clear that pure heroin overdose increased gradually over the years. The fear of the police is the inhibitory factor of the overdose prevention and notification of emergency health care service. Signs of suicide could be the own home as the chosen location for heroin overdose and the presence of partners (“moment of death companion”). Interventions should include simple techniques such as first aid, naloxone administration, resuscitation, prevention of relapse of prisoners and social network extension involving maintenance programs. Orv. Hetil., 2015, 156(9), 352–357.

Opiate- and cocaine-related fatal overdoses in Luxembourg from 1985 to 2011: a study on gender differences

BACKGROUND/AIM

We analysed gender differences in national fatal overdose (FOD) cases related to opiates and cocaine use between 1985 and 2011 (n = 340).

METHODS

Cross-examination of national data from law enforcement and drug use surveillance sources and of forensic evidence. Bivariate and logistic regression analysis of male/female differences according to sociodemographics, forensic evidence and drug use trajectories.

RESULTS

The burden of deaths caused by FOD on the general national mortality was higher for men (PMR/100=0.55) compared with women (PMR/100=0.34). Compared with their male peers, women were younger at the time of death (t=3.274; p=0.001) and showed shorter drug use careers (t=2.228; p=0.028). Heroin use was recorded more frequently in first drug offences of female victims (AOR=6.59; 95% CI 2.97-14.63) and according to forensic evidence, psychotropic prescription drugs were detected to a higher degree in females (AOR=2.019; 95% CI 1.065-3.827).

CONCLUSION

The time window between the onset of illicit drug use and its fatal outcome revealed to be shorter for women versus men included in our study. Early intervention in female drug users, routine involvement of first-line healthcare providers and increased attention to use of poly- and psychotropic prescription drugs might contribute to prevent premature drug-related death and reduce gender differences.

Is opioid substitution treatment beneficial if injecting behaviour continues?

BACKGROUND

Opioid substitution treatment (OST) is recognised as an effective treatment for opioid dependence. Still, a subgroup of OST users continues to inject drugs. This study examines health risks and criminal activity in a population of needle exchange programme (NEP) participants by comparing those identified as current OST users to (i) those identified as former OST users and (ii) those with no OST experience.

METHODS

This was a semi-annual cross-sectional study conducted from 2002 to 2011. NEP participants were interviewed in Oslo, Norway (n=1760); 341 were identified as current OST users, 356 as former OST users and 1063 had no OST experience. The associations between OST status and health risk and criminal activity were assessed through univariate and multiple logistic regression analyses.

RESULTS

Among NEP participants, those currently in OST had fewer non-fatal overdoses (OR=0.5 [95% CI 0.3, 0.9]) compared to former OST users and those never in OST. Additionally, they were less likely to have injected frequently (OR=0.4 [95% CI 0.3, 06]), to have used heroin daily or almost daily (OR=0.3 [95% CI 0.2, 0.4]), and to have committed theft (OR=0.6 [95% CI 0.4, 1.0]) and engaged in drug dealing (OR=0.7 [95% CI 0.5, 0.9]) in the past month. Overall, there was a high level of polysubstance use and no group differences on this measure.

CONCLUSIONS

NEP participants who are currently in OST have substantially reduced health risks and criminal activity than other NEP participants. The high level of polysubstance use nevertheless poses a public health challenge.

Take-home emergency naloxone to prevent heroin overdose deaths after prison release: rationale and practicalities for the N-ALIVE randomized trial

The naloxone investigation (N-ALIVE) randomized trial commenced in the UK in May 2012, with the preliminary phase involving 5,600 prisoners on release. The trial is investigating whether heroin overdose deaths post-prison release can be prevented by prior provision of a take-home emergency supply of naloxone. Heroin contributes disproportionately to drug deaths through opiate-induced respiratory depression. Take-home emergency naloxone is a novel preventive measure for which there have been encouraging preliminary reports from community schemes. Overdoses are usually witnessed, and drug users themselves and also family members are a vast intervention workforce who are willing to intervene, but whose responses are currently often inefficient or wrong. Approximately 10% of provided emergency naloxone is thought to be used in subsequent emergency resuscitation but, as yet, there have been no definitive studies. The period following release from prison is a time of extraordinarily high mortality, with heroin overdose deaths increased more than sevenfold in the first fortnight after release. Of prisoners with a previous history of heroin injecting who are released from prison, 1 in 200 will die of a heroin overdose within the first 4 weeks. There are major scientific and logistical challenges to assessing the impact of take-home naloxone. Even in recently released prisoners, heroin overdose death is a relatively rare event: hence, large numbers of prisoners need to enter the trial to assess whether take-home naloxone significantly reduces the overdose death rate. The commencement of pilot phase of the N-ALIVE trial is a significant step forward, with prisoners being randomly assigned either to treatment-as-usual or to treatment-as-usual plus a supply of take-home emergency naloxone. The subsequent full N-ALIVE trial (contingent on a successful pilot) will involve 56,000 prisoners on release, and will give a definitive conclusion on lives saved in real-world application. Advocates call for implementation, while naysayers raise concerns. The issue does not need more public debate; it needs good science.

Ethanol reversal of cellular tolerance to morphine in rat locus coeruleus neurons

Consumption of ethanol is a considerable risk factor for death in heroin overdose. We sought to determine whether a mildly intoxicating concentration of ethanol could alter morphine tolerance at the cellular level. In rat locus coeruleus (LC) neurons, tolerance to morphine was reversed by acute exposure of the brain slice to ethanol (20 mM). Tolerance to the opioid peptide [d-Ala(2),N-MePhe(4),Gly-ol]-enkephalin was not reversed by ethanol. Previous studies in LC neurons have revealed a role for protein kinase C (PKC)α in μ-opioid receptor (MOPr) desensitization by morphine and in the induction and maintenance of morphine tolerance, but we have been unable to demonstrate that 20 mM ethanol produces significant inhibition of PKCα. The ability of ethanol to reverse cellular tolerance to morphine in LC neurons was absent in the presence of the phosphatase inhibitor okadaic acid, indicating that dephosphorylation is involved. In human embryonic kidney 293 cells expressing the MOPr, ethanol reduced the level of MOPr phosphorylation induced by morphine. Ethanol reversal of tolerance did not appear to result from a direct effect on MOPr since acute exposure to ethanol (20 mM) did not modify the affinity of binding of morphine to the MOPr or the efficacy of morphine for G-protein activation as measured by guanosine 5'-O-(3-[(35)S]thio)triphosphate binding. Similarly, ethanol did not affect MOPr trafficking. We conclude that acute exposure to ethanol enhances the effects of morphine by reversing the processes underlying morphine cellular tolerance.

Reversal of morphine analgesic tolerance by ethanol in the mouse

The chronic use of opioids in humans, accompanied by the development of tolerance, is a dangerous phenomenon in its own right. However, chronic opioid use is often made more dangerous by the coconsumption of other substances. It has been observed that the blood level of opioids in postmortem analyses of addicts, who consumed ethanol along with the opioid, was much less than that observed in individuals who died from opioids alone. This relationship between ethanol and opioids led us to investigate the hypothesis that ethanol alters tolerance to opioids. In the present study, we report that ethanol significantly and dose-dependently reduced the antinociceptive tolerance produced by morphine and the cross-tolerance between [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO) and morphine in the mouse tail-flick test. The reversal of morphine tolerance was partially blocked by both the gamma receptor blocker bicuculline and by the γ-aminobutyric acid (GABA)(B) receptor blocker phaclofen and the administration of both inhibitors completely reversed the effects of ethanol on morphine tolerance. Diazepam, like ethanol, decreased morphine tolerance. However, this inhibition was reversed by the GABA(A) antagonist bicuculline but not by the GABA(B) antagonist phaclofen. These findings have important implications for individuals who abuse opioids and ethanol as well as suggest a mechanism to reduce the amount of opioid needed in chronic pain treatment.

Opioid agonist treatments and heroin overdose deaths in Baltimore, Maryland, 1995-2009

OBJECTIVES

We examined the association between the expansion of methadone and buprenorphine treatment and the prevalence of heroin overdose deaths in Baltimore, Maryland from 1995 to 2009.

METHODS

We conducted a longitudinal time series analysis of archival data using linear regression with the Newey-West method to correct SEs for heteroscedasticity and autocorrelation, adjusting for average heroin purity.

RESULTS

Overdose deaths attributed to heroin ranged from a high of 312 in 1999 to a low of 106 in 2008. While mean heroin purity rose sharply (1995-1999), the increasing number of patients treated with methadone was not associated with a change in the number of overdose deaths, but starting in 2000 expansion of opioid agonist treatment was associated with a decline in overdose deaths. Adjusting for heroin purity and the number of methadone patients, there was a statistically significant inverse relationship between heroin overdose deaths and patients treated with buprenorphine (P = .002).

CONCLUSIONS

Increased access to opioid agonist treatment was associated with a reduction in heroin overdose deaths. Implementing policies that support evidence-based medication treatment of opiate dependence may decrease heroin overdose deaths.

Diversity in causes and characteristics of drug-induced deaths in an urban setting

AIMS

To assess demographic characteristics, treatment utilization and circumstances of death among those who died from drug-induced deaths in an urban setting and to identify possible subpopulations that should be targeted specifically to further develop preventive public health policies.

METHODS

Subjects (N = 231) who died, from drug-induced deaths, in the Norwegian capital Oslo (2006-2008) were identified through the National Cause of Death Registry. Data on toxicology, prison release and contact with health and social services in Oslo were collected.

RESULTS

Majority of cases were men (78%) and the mean age was 37 years. Nearly all cases (90%) were polydrug intoxications. Heroin was implicated in 67%. Residential address was the most common place of death (67%). Most cases (82%) had been in contact with health and social services in the year before death. Women were 4 years older, more often Oslo residents (82% vs. 64%) and fewer died from heroin intoxication. Non-Oslo residents were younger and more likely to have been found outdoors with heroin as the main intoxicant. Other identified subpopulations were those who died after prison release and those discharged from drug treatment.

CONCLUSIONS

The findings suggest that the majority of cases could have been available for preventive measures through their contacts with health and social services. Yet, the heterogeneity among cases indicates that such measures need to be multifaceted. Finally, it is important for policymakers and health and social workers in various countries to consider subpopulations such as women and non-city residents when developing public health interventions to prevent overdose deaths.

Temporal and geographic shifts in urban and nonurban cocaine-related fatal overdoses in British Columbia, Canada

PURPOSE

Illicit drug overdose is a leading cause of premature mortality. We sought to examine fatal overdose trends from 2001 to 2005 in urban and nonurban areas of British Columbia, Canada.

METHODS

We conducted a review of all provincial coroner files in which drug overdose was the cause of death between January 1, 2001, and December 31, 2005. We compared cocaine and non-cocaine-related overdoses and examined temporal changes in cocaine-related mortality rates in urban and nonurban areas. Multilevel mixed effects models were used to determine the independent risk factors for cocaine-related death. Spatial analyses were conducted to identify clusters of these cases.

RESULTS

During the study period, 904 illicit drug overdoses were recorded, including 369 (40.8%) in nonurban areas and 532 (58.9%) related to cocaine consumption. In a multilevel model, we observed a significant interaction (p = .010) between population density and year, indicating a considerable and differential increase in the likelihood of cocaine-related deaths in nonurban areas. Cocaine-related deaths were clustered in the southeast region of the province.

CONCLUSIONS

Cocaine-related overdoses in nonurban areas should be a public health concern. Evidence-based interventions to reduce the risks associated with cocaine consumption and reach drug users in nonurban settings are needed.

Alcohol-related brief intervention in patients treated for opiate or cocaine dependence: a randomized controlled study

BACKGROUND

Despite the importance of heavy drinking and alcohol dependence among patients with opiate and cocaine dependence, few studies have evaluated specific interventions within this group. The aim of the present study was to evaluate the impact of screening with the Alcohol Use Disorders Identification Test (AUDIT) and of brief intervention (BI) on alcohol use in a sample of patients treated for opioid or cocaine dependence in a specialized outpatient clinic.

METHODS

Adult outpatients treated for opioid or cocaine dependence in Switzerland were screened for excessive alcohol drinking and dependence with the AUDIT. Patients with AUDIT scores that indicated excessive drinking or dependence were randomized into two groups--treatment as usual or treatment as usual together with BI--and assessed at 3 months and 9 months.

RESULTS

Findings revealed a high rate (44%) of problematic alcohol use (excessive drinking and dependence) among patients with opiate and cocaine dependence. The number of drinks per week decreased significantly between T0 (inclusion) and T3 (month 3). A decrease in average AUDIT scores was observed between T0 and T3 and between T0 and T9 (month 9). No statistically significant difference between treatment groups was observed.

CONCLUSIONS

In a substance abuse specialized setting, screening for alcohol use with the AUDIT, followed by feedback on the score, and use of alcohol BI are both possibly useful strategies to induce changes in problematic alcohol use. Definitive conclusions cannot, however, be drawn from the study because of limitations such as lack of a naturalistic group. An important result of the study is the excellent internal consistency of AUDIT in a population treated for opiate or cocaine dependence.

Deaths of opiate/opioid misusers involving dihydrocodeine, UK, 1997-2007

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Dihydrocodeine (DHC) is an opioid analgesic sometimes prescribed as an alternative to other medications (e.g. methadone and buprenorphine) for opioid misuse. Its effectiveness is, however, still controversial. DHC prescription rates seem to be related to levels of DHC fatalities, possibly in relation to levels of disregard of the availability of supervised or interval dispensing of opioids, but no large-scale analysis of DHC fatalities has been carried out. We analysed here involvement of DHC in fatalities that occurred between 1997 and 2007 among individuals with a history of opiate/opioid misuse reported to the National Programme on Substance Abuse Deaths (np-SAD).

WHAT THIS STUDY ADDS

DHC, either alone or in combination, was identified in 584 fatalities. Typical cases identified were males in their early thirties. In accidental overdoses, DHC, which had been prescribed to 45% of the victims, was typically identified in combination with other drugs, such as heroin/morphine, methadone and hypnotics/sedatives. Both paracetamol and antidepressants were more typically identified in combination with DHC in suicides. Opiate/opioid misusers should be educated about risks associated with polydrug intake and prescribers should carefully consider a pharmacological intervention alternative to DHC (e.g. methadone, buprenorphine) when managing and treating opiate addiction.

AIMS

Although its effectiveness is somewhat controversial, it appears that dihydrocodeine (DHC) is still prescribed in the UK as an alternative to both methadone and buprenorphine for the treatment of opiate addiction.

METHODS

Data covering the period 1997-2007 voluntarily supplied by coroners were analysed. All cases pertaining to victims with a clear history of opiate/opioid misuse and in which DHC, either on its own or in combination, was identified at post-mortem toxicology and/or implicated in death, were extracted from the database.

RESULTS

Dihydrocodeine, either alone or in combination, was identified in 584 fatalities meeting the selection criteria. In 44% of cases it was directly implicated in the cause of death. These cases represented about 6.8% of all opiate/opioid-related deaths during this period. Typical DHC cases identified were White males in their early thirties. Accidental deaths (96%) were likely to involve DHC in combination with other psychoactives, mainly heroin/morphine, hypnotics/sedatives and methadone. Both paracetamol and antidepressants were found in proportionately more suicide cases than in accidental overdoses. DHC had been prescribed to the decedent in at least 45% of cases.

CONCLUSIONS

Opiate/opioid misusers should be educated about risks associated with polydrug intake. More in particular, co-administration of DHC with heroin, methadone and benzodiazepines may increase the risk of accidental fatal overdose. Prescribers should carefully consider pharmacological intervention alternative to DHC (e.g. methadone, buprenorphine) when managing and treating opiate addiction. More resources are required to do prospective research in this area.

Development of a coroner-based surveillance system for drug-related deaths in Los Angeles county

Existing data sources do not provide comprehensive and timely information to adequately monitor drug-related mortality in Los Angeles County. To fill this gap, a surveillance system using coroner data was developed to examine patterns in drug-related deaths. The coroner provided data on all injury deaths in Los Angeles County. A list of keywords that indicate a death was caused by drug use was developed. The cause of death variables in the coroner data were searched for mentions of one of the keywords; if a keyword was detected, that death was classified as drug related. The effectiveness of the keyword list in classifying drug-related deaths was evaluated by matching records in the coroner death data to records in the state death files. Then, the drug-related deaths identified using the keywords were compared to drug-related deaths in the state mortality files identified using International Classification of Death codes. Toxicological test results were used to categorize drug-related deaths based on the type and legality of the drug(s) ingested. Mortality rates were calculated for each category of drug and legal status and for different demographic groups. Compared to the gold standard state mortality files, the coroner data had a sensitivity of 95.6% for identifying drug-related deaths. Over three quarters of all drug-related deaths tested positive for opiates and/or stimulants. Males, Whites, and 35-54-year-olds each accounted for more than half of all drug-related deaths. The surveillance of drug-related deaths using coroner data has several advantages: data are available in a timely fashion, the data include information about the specific substances each victim ingested, and the data can be broken down to compare mortality among specific subpopulations.

Does alcohol increase the risk of overdose death: the need for a translational approach

BACKGROUND

We argue for a translational approach to addiction science, using an important current research question as a case study.

CASE STUDY

What is the evidence in support of the hypothesis that alcohol increases the risk of a heroin/opiate overdose through a pharmacological interaction?

FINDINGS

The positive epidemiological evidence shows that opiate overdose deaths rarely involve a single drug; that alcohol is the most common other drug involved; that there is a negative association between alcohol and morphine concentration at post mortem; and that post-mortem levels of morphine are often below the levels expected of highly tolerant individuals. The evidence is consistent with the hypothesis that heroin users who drink may require less heroin to overdose than those who do not drink (all other factors being equal) because of a pharmacological interaction. However, the evidence is consistent with, and does not rule out, other causal (and non-causal) pathways. Alcohol could be associated negatively with tolerance, or confounded by other factors. Experimental evidence is required which is unlikely to be obtained through further epidemiological study or through randomized clinical trials.

CONCLUSIONS

We believe that animal models could provide the key evidence to test the hypothesis for a 'pharmacodynamic' or 'pharmacokinetic' interaction, which could be corroborated in clinical challenge studies and epidemiological studies. Such a translational approach demands greater collaboration between addiction scientists from basic to applied science and from neuroscience to social science, and would be able to address other key research questions and hypotheses in addiction.