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.

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.

[Accidental ingestion of methadone and buprenorphine by children. A case review of the Lille Poison Centre between 1995 and 2005]

We have performed a retrospective study (1995-2005) on 218 accidental intoxications in children less than 15 years old, linked to drugs used in the management of opiate withdrawal (cases registered at the Lille poison centre) This study shows a peak of frequency in children less than 3 years old, with a predominance of boys. Poisonings with buprenorphine are more frequent but ingestions of methadone are often more severe (p = 0.004).

Centers for Disease Control and Prevention (CDC). Buprenorphine prescribing practices and exposures reported to a poison center--Utah, 2002-2011

Buprenorphine is an effective medication for the treatment of opioid dependence. Its use has increased in the United States as a result of the Drug Addiction Treatment Act of 2000, which allowed physicians to prescribe certain medications as part of office-based treatment for opioid addiction. In France, widespread use of medication-assisted therapy, primarily buprenorphine treatment, was associated with an 80% decrease in overdose deaths from heroin or cocaine from 465 in 1996 to 89 in 2003. With the expanded use of buprenorphine, an increase in exposures among children and adults has been reported in the United States. These exposures (including unintentional and intentional, therapeutic and nontherapeutic) have resulted in adverse effects and, in a small number of cases, death. To assess statewide increases in buprenorphine use and the number of reported exposures, the Utah Department of Health analyzed data from the Utah Controlled Substance Database (CSD) and the Utah Poison Control Center (PCC). The results of that analysis indicated a statewide increase in the annual number of patients prescribed buprenorphine from 22 in 2002 to 9,793 in 2011, and a concurrent increase in the annual number of prescribers writing buprenorphine prescriptions from 16 to 1,088. Over the same period, the number of exposures to buprenorphine reported annually to the PCC increased from six to 81. However, comparison of the ratios of buprenorphine exposures to patients and prescribers in 2002 with data for 2011 indicated substantial decreases from 6/22 for patients and 6/16 for prescribers in 2002 to 81/9,793 for patients and 81/1,088 for prescribers in 2011. Three of the total 462 buprenorphine exposures reported during 2002-2011 in Utah, in a teen and two adults, were associated with fatal outcomes. Increased buprenorphine prescribing in Utah during 2002-2011 likely represents expanded access to critically needed opioid addiction treatment; however, safeguards should be in place to prevent adverse effects. Prescribers and pharmacists are encouraged to counsel patients carefully regarding the safe use, storage, and disposal of buprenorphine.

Why buprenorphine is so successful in treating opiate addiction in France

In France, all registered medical doctors have been allowed to prescribe buprenorphine without any special education or licensing since 1995. This has led to a rapidly increasing number of opiate-dependent users under buprenorphine treatment in primary care. French physician compensation mechanisms, pharmacy services, and medical insurance funding all have contributed to minimizing barriers to buprenorphine treatment. Approximately 20% of all physicians in France are prescribing buprenorphine to treat more than one half of the estimated 180,000 problem heroin users. Intravenous diversion of buprenorphine may occur in up to 20% of buprenorphine patients and has led to relatively rare overdoses in combination with sedatives, whereas total opiate overdose deaths have declined substantially. In France, buprenorphine maintenance treatment for problem opiate users was feasible and safe through office-based prescriptions in a relaxed regulatory environment.

Suboxone (buprenorphine/naloxone) toxicity in pediatric patients: a case report

BACKGROUND

Suboxone, a combination of buprenorphine and naloxone in sublingual tablet form, was recently approved in the United States for management of opioid dependence. Little information exists regarding the potential for opioid toxicity after Suboxone exposure in the pediatric population. We report a case of opioid toxicity after exposure to Suboxone in a pediatric patient and a review of other cases of pediatric Suboxone ingestion in the literature.

CASE

A previously healthy 2-year-old boy was found with 1 tablet of Suboxone (8 mg buprenorphine/2 mg naloxone) in his mouth. Remnants of the partly dissolved tablet were immediately removed from the child's oropharynx. The child experienced 1 episode of spontaneous emesis and became drowsy en route to the emergency department 30 minutes after the exposure. The patient was observed in the emergency department; no interventions were necessary, and the child was discharged asymptomatic and stable 6 hours post ingestion.

CONCLUSION

Suboxone, a combination of buprenorphine and naloxone, may produce opioid toxicity via sublingual absorption or ingestion by children. We present the case of a child with mild central nervous system depression after exposure to Suboxone. Pediatric case reports that demonstrate more significant central nervous system and respiratory depressant effects from Suboxone ingestion are emerging.

A survey of buprenorphine related deaths in Singapore

Buprenorphine is available in Singapore as substitution treatment for opioid dependence since 2002. This study surveys buprenorphine related deaths in Singapore between September 2003 and December 2004. The aims are to establish the autopsy prevalence of buprenorphine related deaths and the demographical and toxicological profile of the cases. Toxicological screening was performed for all unnatural deaths, deaths involving known drug addicts, as well as when autopsy revealed no obvious cause of death. Twenty-one cases had buprenorphine detected in post-mortem blood and/or urine samples. Eighteen were sudden deaths. There were two fatal falls from height and one death by hanging. All subjects were male. The age range was 24-48 years. Fourteen subjects were between 30 and 39 years of age. The mean age was 35 years. The majority (62%) were Chinese. Eleven (52%) were known drug abusers. For sudden deaths, two groups were identified. Six cases died from natural causes. Blood buprenorphine levels ranged from undetected (detected in urine) to 3.2 ng/mL (mean 1.4 ng/mL). Twelve cases were attributed directly and indirectly to mixed drug poisoning. Blood buprenorphine levels ranged from undetected (detected in urine) to 17 ng/mL (mean 3.2 ng/mL). Nineteen cases showed concurrent abuse of buprenorphine and benzodiazepine, diazepam being the most frequently detected, followed by nitrazepam and midazolam. The availability of buprenorphine as substitution therapy is associated with an increase in buprenorphine related deaths. The danger of co-abuse of buprenorphine and benzodiazepines is highlighted.

Adverse effects in children after unintentional buprenorphine exposure

Buprenorphine in sublingual formulation was recently introduced to the American market for treatment of opioid dependence. We report a series of 5 toddlers with respiratory and mental-status depression after unintentional buprenorphine exposure. Despite buprenorphine's partial agonist activity and ceiling effect on respiratory depression, all children required hospital admission and either opioid-antagonist therapy or mechanical ventilation. Results of routine urine toxicology screening for opioids were negative in all cases. Confirmatory testing was sent for 1 child and returned with a positive result. The increasing use of buprenorphine as a home-based therapy for opioid addiction in the United States raises public health concerns for the pediatric population.

Fatal poisoning in methadone and buprenorphine treated patients -- are there differences?

BACKGROUND

Some recent studies have suggested a lower risk of fatal intoxications in drug-dependent patients under buprenorphine compared to methadone treatment.

METHODS

Epidemiological reference data for the Munich region suggest that in 2003 approximately 10 % of all substitution patients were treated with buprenorphine, and 87 % with methadone. We studied the proportion of patients under methadone and buprenorphine substitution among drug-related deaths. Data from forensic post-mortem and toxicological analysis were analyzed.

RESULTS

Data indicate that in 96 (35 %) of all 272 so-called drug deaths, methadone was involved compared to a single case of buprenorphine, possibly indicating a relatively better risk profile of buprenorphine.

DISCUSSION

More prospective studies are necessary to assess the risk of fatal intoxications under different substitution regimens.

[Comparative evaluation of clinical symptoms and status of bone metabolism in patients with heroin and buprenorphine addiction in the period of withdrawal]

The purpose of this study was the evaluation of clinical heroin symptoms and buprenorphine drug addiction in the withdrawal period with the purpose of their comparison, study of parameters of bone metabolism in the both groups. In the study group were included 40 patients with heroin and 27 with buprenorphine addiction in the period of abstinence. Our investigations have shown, that in the both groups, among clinical symptoms ossalgias, arthralgias and mialgias attributes to the expressed dysfunction of vegetative system, were most prominent. Decrease of sexual functions was found in half of inspected patients. Biochemical investigations have shown intensive clearance of calcium with the urine that indicates intensifying resorbtion processes in the bone tissue. Symptoms of hypogonadism were accompanied by the decrease of the level of testosterone in the blood. Parameters of mineral consistency of the bone tissue was decreased both in patients with heroin and buprenorphine addiction.

Buprenorphine mortality, seizures and prescription data in the UK, 1980-2002

Buprenorphine safety in overdose has been debated recently, but no mortality data related to this compound from the UK have been published. To gather together all of the buprenorphine mortality figures, a number of different sources have been checked. To inform on buprenorphine safety issues, accessible information related to its availability indicators (i.e. prescriptions; seizures) data for the 1980-2002 time frame have been sought. In the UK, during this period, buprenorphine was mentioned in 43 fatalities. Typically, victims were males in the 25-44 age group. In 12 cases (28% of total), a verdict of suicide was given. Buprenorphine was detected on its own in seven cases; more frequently, it was found together with benzodiazepines and other opiates. Large quantities of buprenorphine were prescribed both in England in 1985-1989 and in 1991-1992 in Scotland, where seizures reached their highest levels. Buprenorphine prescriptions seemed to peak again after 1999, when high dose buprenorphine formulations entered the UK market. No positive correlation was found between the number of buprenorphine deaths over the years and either buprenorphine dispensings/prescriptions or seizures. However, an increase in buprenorphine-related deaths since 1999 was identified and this may be an issue which should be carefully monitored over the next few years.

A critical review of the causes of death among post-mortem toxicological investigations: analysis of 34 buprenorphine-associated and 35 methadone-associated deaths

AIMS

To assess the trends in the number, mortality and the nature of forensic cases involving toxicological detection of buprenorphine or methadone among toxicological investigations performed in Paris from June 1997 to June 2002.

DESIGN

Retrospective, 5 year study with review of premortem data, autopsy, police reports, hospital data, and post-mortem toxicological analyses.

SETTING AND PARTICIPANTS

34 forensic cases of buprenorphine and 35 forensic cases of methadone detection among 1600 toxicological investigations performed at the Laboratory of Toxicology in the Medical Examiner's Office in Paris.

MEASUREMENTS AND RESULTS

Therapeutic, toxic or lethal drug concentrations were defined based upon the results of blood analyses and the published literature. Drug concentrations were cross-referenced with other available ante- and post-mortem data. Subsequently, we classified a 'clear responsibility', 'possible responsibility' or 'not causative' role for buprenorphine or methadone in the death process, or 'no explanation of death'. Buprenorphine and methadone can be regarded as being directly implicated in, respectively, four of 34 death cases (12%) and three of 35 death cases (9%), and their participation in the lethal process is strongly plausible in eight (buprenorphine) and 11 (methadone) additional deaths.

CONCLUSIONS

Analysis of causes of death reveals the difficulties in determining the role of substitution drugs in the death process, as many other factors may be involved, including circumstances surrounding death, past history, differential selection of subjects into either substitution modality and concomitant intake of other drugs (especially benzodiazepines and neuroleptics). The potential for synergistic or additive actions by other isolated molecules-particularly opioids, benzodiazepines, other psychotropes and alcohol-must be also considered.

Serious overdoses involving buprenorphine in Helsinki

BACKGROUND

Buprenorphine is used as maintenance therapy for opioid-dependent patients. In comparison with other opioids it is thought to be safer because it is less likely to cause serious respiratory depression. However, concomitant use of psychotropics, especially benzodiazepines, and intravenous injection of dissolved buprenorphine tablets increase the risk of a serious overdose.

METHODS

As part of a larger retrospective study of opioid overdoses in Helsinki, the emergency medical services (EMS) records from January 1995 to April 2002 were reviewed for overdoses involving buprenorphine. Hospital records were reviewed when available.

RESULTS

We report 11 overdoses in which buprenorphine was involved. The classic symptoms and signs of an opioid overdose (respiratory depression, miosis and central nervous system depression) were present in most of the cases. At least eight of the patients had an overdose that was potentially fatal. One of the patients had a heroin overdose and was reportedly 'treated' by his friends with intravenously administered buprenorphine.

CONCLUSION

The high-dosage formulation of buprenorphine used for opioid-dependent patients might have caused several dangerous and potentially fatal overdoses in Helsinki. However, it does cause considerably less serious overdoses than heroin. Drug abusers might be intravenously administering buprenorphine themselves to treat heroin overdoses.

A new series of 13 buprenorphine-related deaths

OBJECTIVES

Buprenorphine at high dosage became available in France in 1996, as a substitution treatment for heroin addicts. Since this date, numerous deaths were attributed to this drug. This paper reports a new series of 13 fatalities involving buprenorphine observed at the Institute of Legal Medicine of Strasbourg, between August 2000 to October 2001.

DESIGN AND METHODS

During the mentioned period, about 800 forensic cases were screened at the laboratory. Buprenorphine and its primary metabolite norbuprenophine were assayed in postmortem specimens by HPLC/MS. From these 13 subjects, 11 were male. Blood levels ranged from 0.3 to 7.7 ng/mL (mean 3.5 ng/mL) and 0.3 to 16.2 ng/mL (mean 2.9 ng/mL) for buprenorphine and norbuprenorphine, respectively. The mean values appear to be within the therapeutic range.

CONCLUSIONS

IV injection of crushed tablets, a concomitant intake of psychotropics (especially benzodiazepines and neuroleptics) and the high dosage of the buprenorphine formulation available in France appear as the major risk factors for such fatalities.

Deaths involving buprenorphine: a compendium of French cases

Buprenorphine at high dosage became available in France in 1996, as a substitution treatment for heroin addicts. Since this date, numerous deaths were attributed to this drug. This paper reports two original series of 39 and 78 fatalities involving buprenorphine observed at the Institute of Legal Medicine of Strasbourg and at 13 other French forensic centers, respectively. The files were recorded from January 1996-May 2000. The first 20 fatalities that were previously published were excluded from this epidemiological study. From these 117 subjects, 96 were male (82%). Buprenorphine and its primary metabolite norbuprenophine were assayed in post-mortem blood by HPLC/MS (n=11 labs) or by GC/MS (n=3 labs). Blood levels for buprenorphine ranged from 0.5 to 51.0ng/ml (mean 10.2ng/ml) and 0.1 to 76ng/ml (mean 12.6ng/ml) in Strasbourg and the other centers, respectively. Blood levels for norbuprenorphine ranged from 0.2 to 47.1ng/ml (mean 8.2ng/ml) and <0.1 to 65ng/ml (mean 10.6ng/ml) in Strasbourg and the other centers, respectively. The mean values appear to be within the therapeutic range. Buprenorphine was identified in 24 of the 26 hair samples assayed in Strasbourg, at concentrations ranging from 10 to 1080pg/mg. Intravenous injection of crushed tablets, a concomitant intake of psychotropics (especially benzodiazepines and neuroleptics) and the high dosage of the buprenorphine formulation available in France appear as the major risk factors for such fatalities. In addition, two suicide-related deaths were also observed, with blood buprenorphine concentrations at 144 and 3276ng/ml.

[Accidental narcotic and buprenorphine poisoning in children notified at the Marseille Poison Center between 1993 and 1999]

To evaluate the frequency and severity of accidental poisoning in children by narcotics or buprenorphine, a retrospective study was carried out: 75 cases were collected by the Marseille Poison Centre between 1993 and 1999. Most of the patients were between 1 and 3 years old and the drugs involved were cannabis and, more recently, Subutex (buprenorphine). These two drugs were responsible for the most severe cases of poisoning, most of which occurred at home.

Fatal intoxication following self-administration of a massive dose of buprenorphine

Several drug packages, including Subutex (high-dose buprenorphine, as sublingual tablets) boxes, were found near the corpse of a 25-year-old male drug addict, who apparently had committed suicide. The autopsy revealed a fatal respiratory depression. The toxicological investigations concluded that death resulted from massive burpienorphine intoxication. The determination of buprenorphine (BU) and norbuprenorphine (NBU) in all biological specimens was performed by liquid chromatography-electrospray mass spectrometry (LC-ES-MS) after hydrolysis (for solid tissues), deproteinization of the matrices, and solid-phase extraction of the compounds. Exceptionally high concentrations of BU and NBU were found in blood (3.3 and 0.4 mg/L, respectively), urine (3.4 and 0.6 mg/L), bile (2035 and 536 mg/L and brain (6.4 a nd 3.9 microg/g). The high concentration of BU (899 mg/L) and the absence of NBU in gastric liquid suggested oral intake. High concentrations of amino-7-flunitra/epam, the main metabolite of flunitra/epam, were also found in blood, urine and gastric liquid. This benzodiazepine may have been a co-factor in the toxic effects of BU.

[Hepatonephritis and massive ingestion of buprenorphine]

We present a case of a severe hepatitis associated with acute renal failure and anuria consequently to the ingestion of 112 mg of buprenorphine, 48 hours before. The normalisation of hepatic and renal functions is associated with discontinuation of buprenorphine administration and hemodialysis treatment. Buprenorphine seems to be directly responsible for this hepatonephritis as indicated by the high plasmatic levels of buprenorphine (224 ng/ml) and norbuprenorphine (30 ng/ml) never described until now. Buprenorphine toxicity could be due to the inappropriate ingestion mode (oral instead of sublingual) and could be increased by previous acetaminophen intake.

Buprenorphine-related deaths among drug addicts in France: a report on 20 fatalities

This paper reports a series of 20 fatalities involving a high-dose, sublingual buprenorphine (BUP) formulation recently marketed in France for the substitutive therapy of opiate addicts. The files were recorded over a 16-month period from five different urban areas in France. All subjects but one were male, aged 14-48 (mean 26.6). BUP and its primary metabolite norbuprenorphine (norBUP) were assayed in postmortem fluids and viscerae by HPLC-MS. Blood levels for BUP and norBUP ranged from 1.1 to 29.0 ng/mL (mean 8.4 ng/mL) and 0.2 to 12.6 ng/mL (mean 2.6 ng/mL), respectively, that is, within or slightly over the therapeutic range. BUP exhibited extensive tissue distribution, with average postmortem concentrations of 6.0, 35.0, 45.5, and 80.0 ng/g in the myocardium, kidney, brain, and liver, respectively. In blood, as in viscerae, norBUP levels were generally lower than BUP. The highest concentrations were found in the bile for both BUP (range 575-72,650 ng/mL) and norBUP (range 41-30,000 ng/mL). Therefore, bile may represent a sample of choice for postmortem screening. BUP was identified in 9 of the 11 hair samples assayed at concentrations ranging from 6 to 597 ng/g (mean 137 ng/g), whereas norBUP was never detected. Intravenous injection of crushed tablets, a concomitant intake of psychotropics (especially benzodiazepines), and the high dosage of the BUP formulation available in France appear to be the major risk factors for such fatalities.

[Acute poisoning during substitution therapy based on high-dosage buprenorphine. 29 clinical cases--20 fatal cases]

OBJECTIVES

Buprenorphine has been an important advance in care for drug abusers, but the toxic risk may be fatal. We report here two original series of buprenorphine poisoning in opiate abusers on substitution therapy.

PATIENTS

The first series included 20 males and 9 females, aged 20-35 years (mean = 27.5) with non-fatal poisoning. The second series included 20 subjects (19 males, 1 female) aged 14-48 years (mean = 26.6) with a fatal outcome. All subjects were opiate addicts taking high-dosage sublingual buprenorphine formulation as substitution therapy.

RESULTS

Blood concentrations of buprenorphine were found in all cases to remain at a low level (1.0-2.3 ng/ml, m = 1.4 ng/ml, and 1.1-29.0 ng/ml, m = 8.4 ng/ml in non-fatal and fatal cases respectively). Almost all cases involved concomitant intake of psychotropic medications, especially benzodiazepines (18 non-fatal and 17 fatal cases).

DISCUSSION

These observations confirm previously reported data on the danger of buprenorphine-benzodiazepine combinations. Intravenous injection of crushed tablets also appears to be a risk factor (8 deaths and 10 non-fatal poisonings). This series highlights the need for improvement in the recently developed French program for substitution therapy with high-dosage buprenorphine in heroin addicts.

Overdosage of buprenorphine: case report

A recent addition to the list of analgesics, buprenorphine, is still under trial. This paper reports the ingestion of a large dose taken with suicidal intent. Symptoms were minimal and recovery complete.