Fatal versus non-fatal heroin "overdose": blood morphine concentrations with fatal outcome in comparison to those of intoxicated drivers

Heroin-Related Fatalities in Jeddah, Saudi Arabia, between 2008 and 2018

To date, epidemiological studies have not evaluated heroin-related deaths in the Middle East and North African regions, especially Saudi Arabia. All heroin-related postmortem cases reported at the Jeddah Poison Control Center (JPCC) over a 10-year period (21 January 2008 to 31 July 2018) were reviewed. In addition, liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was utilized to determine the 6-monoacetylmorphine (6-MAM), 6-acetylcodeine (6-AC), morphine (MOR), and codeine contents in unhydrolyzed postmortem specimens. Ninety-seven heroin-related deaths were assessed in this study, and they represented 2% of the total postmortem cases at the JPCC (median age, 38; 98% male). In the blood, urine, vitreous humor, and bile samples, the median morphine concentrations were 280 ng/mL, 1400 ng/mL, 90 ng/mL, and 2200 ng/mL, respectively; 6-MAM was detected in 60%, 100%, 99%, and 59% of the samples, respectively; and 6-AC was detected in 24%, 68%, 50%, and 30% of the samples, respectively. The highest number of deaths (33% of total cases) was observed in the 21-30 age group. In addition, 61% of cases were classified as "rapid deaths," while 24% were classified as "delayed deaths." The majority (76%) of deaths were accidental; 7% were from suicide; 5% were from homicide; and 11% were undetermined. This is the first epidemiological study to investigate heroin-related fatalities in Saudi Arabia and the Middle East and North African region. The rate of heroin-related deaths in Jeddah remained stable but increased slightly at the end of the study period. Most patients were heroin-dependent abusers and from the middle-aged group. The availability of urine, vitreous humor, and bile specimens provided valuable information regarding the opioids that were administered and the survival time following heroin injection.

Pharmacological data science perspective on fatal incidents of morphine treatment

Morphine prescribed for analgesia has caused drug-related deaths at an estimated incidence of 0.3% to 4%. Morphine has pharmacological properties that make it particularly difficult to assess the causality of morphine administration with a patient's death, such as its slow transfer between plasma and central nervous sites of action and the existence of the active metabolite morphine-6-glucuronide with opioid agonistic effects, Furthermore, there is no well-defined toxic dose or plasma/blood concentration for morphine. Dosing is often adjusted for adequate pain relief. Here, we summarize reported deaths associated with morphine therapy, including associated morphine exposure and modulating patient factors such as pharmacogenetics, concomitant medications, or comorbidities. In addition, we systematically analyzed published numerical information on the stability of concentrations of morphine and its relevant metabolites in biological samples collected postmortem. A medicolegal case is presented in which the causality of morphine administration with death was in dispute and pharmacokinetic modeling was applied to infer the administered dose. The results of this analytical review suggest that (i) inference from postmortem blood concentrations to the morphine dose administered has low validity and (ii) causality between a patient's death and the morphine dose administered remains a highly context-dependent and collaborative assessment among experts from different medical specialties.

Electrochemical Determination of Morphine in Urine Samples by Tailoring FeWO4/CPE Sensor

Morphine (MORPH) is natural alkaloid and mainly used as a pain reliever. Its monitoring in human body fluids is crucial for modern medicine. In this paper, we have developed an electrochemical sensor for submicromolar detection of MORPH. The sensor is based on modified carbon paste electrode (CPE) by investigating the Fe_xW_1-xO₄ ratio in iron tungstate (FeWO₄), as well as the ratio of this material in CPE. For the first time, the effect of the iron-tungsten ratio in terms of achieving the best possible electrochemical characteristics for the detection of an important molecule for humans was examined. Morphological and electrochemical characteristics of materials were studied. The best results were obtained using Fe₁W₃ and 7.5% of modifier in CPE. For MORPH detection, square wave voltammetry (SWV) was optimized. Under the optimized conditions, Fe₁W₃@CPE resulted in limit of detection (LOD) of the method of 0.58 µM and limit of quantification (LOQ) of 1.94 µM. The linear operating range between 5 and 85 µM of MORPH in the Britton-Robinson buffer solution (BRBS) at pH 8 as supporting electrolyte was obtained. The Fe₁W₃@CPE sensor resulted in good selectivity and excellent repeatability with relative standard deviation (RSD) and was applied in real-world samples of human urine. Application for direct MORPH detection, without tedious sample pretreatment procedures, suggests that developed electrochemical sensor has appeared to be a suitable competitor for efficient, precise, and accurate monitoring of the MORPH in biological fluids.

Role of β-arrestin-2 in short- and long-term opioid tolerance in the dorsal root ganglia

G-protein-biased agonists with reduced β-arrestin-2 activation are being investigated as safer alternatives to clinically-used opioids. β-arrestin-2 has been implicated in the mechanism of opioid-induced antinociceptive tolerance. Opioid-induced analgesic tolerance is classically considered as centrally-mediated, but recent reports implicate nociceptive dorsal root ganglia neurons as critical mediators in this process. Here, we investigated the role of β-arrestin-2 in the mechanism of opioid tolerance in dorsal root ganglia nociceptive neurons using β-arrestin-2 knockout mice and the G-protein-biased μ-opioid receptor agonist, TRV130. Whole-cell current-clamp electrophysiology experiments revealed that 15-18-h overnight exposure to 10 μM morphine in vitro induced acute tolerance in β-arrestin-2 wild-type but not knockout neurons. Furthermore, in wild-type neurons circumventing β-arrestin-2 activation by overnight treatment with 200 nM TRV130 attenuated tolerance. Similarly, acute morphine tolerance in vivo in β-arrestin-2 knockout mice was prevented in the warm-water tail-withdrawal assay. Treatment with 30 mg/kg TRV130 s.c. also inhibited acute antinociceptive tolerance in vivo in wild-type mice. Alternately, in β-arrestin-2 knockout neurons tolerance induced by 7-day in vivo exposure to 50 mg morphine pellet was conserved. Likewise, β-arrestin-2 deletion did not mitigate in vivo antinociceptive tolerance induced by 7-day exposure to 25 mg or 50 mg morphine pellet in both female or male mice, respectively. Consequently, these results indicated that β-arrestin-2 mediates acute but not chronic opioid tolerance in dorsal root ganglia neurons and to antinociception in vivo. This suggests that opioid-induced antinociceptive tolerance may develop even in the absence of β-arrestin-2 activation, and thus significantly affect the clinical utility of biased agonists.

Heroin overdose masquerades as methomyl poisoning: a case report

BACKGROUND

Methomyl is the most common cause of suicidal death but heroin is the most common cause of accidental death. The problem is to determine the exact cause and manner of death between methomyl or heroin toxicity. The evidence from autopsy includes crime scene investigation, toxicological analysis by liquid chromatography with mass spectrometry, and knowledge of methomyl and heroin intoxication.

CASE PRESENTATION

A 35-year-old Thai man and a 30-year-old Thai woman were found showing evidence of cyanosis, with a fine froth around the nose and mouth. Postmortem interval time was 24 hours. According to the police's and hotel owner's records, the couple stayed together for 1 day before being found dead in bed, naked, with a foul and a fine froth around the nose and mouth. A methomyl insecticide sachet and a plastic box containing white powder form of heroin were found at the scene. Laboratory tests of the male corpse identified the presence of methomyl in the blood of the stomach and morphine, codeine, methadone, and tramadol in the systemic blood. Blood cholinesterase enzyme activity and morphine concentration was 3416 U/L or 53% (normal 6400 U/L) and 0.058 μg/ml respectively. Laboratory test of the female corpse identified the presence of methomyl in the stomach and blood, and cholinesterase enzyme activity was 1965 U/L or 30.7%.

CONCLUSIONS

Cause of death of the male corpse was deemed to be due to heroin intoxication as the blood concentration of morphine was more than the lethal concentration with a morphine/codeine ratio of more than 1:1. Methomyl intoxication of the male corpse was unlikely to be the cause of death because methomyl systemic blood concentration was found to be very low, < 2.5 μg/ml, and cholinesterase enzyme levels did not indicate lethal activity (< 10-15% of normal). The main problem regarding an insurance claim is that the policy will not pay out in the case of heroin-associated deaths, as it is an addictive drug. The policy would pay out on death by suicide with methomyl insecticide, which was not prohibited by the insurance company after 1 year of insurance. So, it is not clear whether or not the family will receive money from the insurance company.

Rapid Discovery of Illuminating Peptides for Instant Detection of Opioids in Blood and Body Fluids

The United States is currently experiencing an opioid crisis, with more than 47,000 deaths in 2017 due to opioid overdoses. Current approaches for opioid identification and quantification in body fluids include immunoassays and chromatographic methods (e.g., LC-MS, GC-MS), which require expensive instrumentation and extensive sample preparation. Our aim was to develop a portable point-of-care device that can be used for the instant detection of opioids in body fluids. Here, we reported the development of a morphine-sensitive fluorescence-based sensor chip to sensitively detect morphine in the blood using a homogeneous immunoassay without any washing steps. Morphine-sensitive illuminating peptides were identified using a high throughput one-bead one-compound (OBOC) combinatorial peptide library approach. The OBOC libraries contain a large number of random peptides with a molecular rotor dye, malachite green (MG), that are coupled to the amino group on the side chain of lysine at different positions of the peptides. The OBOC libraries were then screened for fluorescent activation under a confocal microscope, using an anti-morphine monoclonal antibody as the screening probe, in the presence and absence of free morphine. Using this novel three-step fluorescent screening assay, we were able to identify the peptide-beads that fluoresce in the presence of an anti-morphine antibody, but lost fluorescence when the free morphine was present. After the positive beads were decoded using automatic Edman microsequencing, the morphine-sensitive illuminating peptides were then synthesized in soluble form, functionalized with an azido group, and immobilized onto microfabricated PEG-array spots on a glass slide. The sensor chip was then evaluated for the detection of morphine in plasma. We demonstrated that this proof-of-concept platform can be used to develop fluorescence-based sensors against morphine. More importantly, this technology can also be applied to the discovery of other novel illuminating peptidic sensors for the detection of illicit drugs and cancer biomarkers in body fluids.

Intentional heroin administration resulting in homicide in a 10-month old infant

Homicide occurs in approximately one in five injury-related deaths among infants in the United States and studies suggest that male caretakers (fathers or mothers' intimate partners) are the perpetrators of the majority of infant homicides. Opioid abuse is common and it is estimated that between 26.4 million and 36 million people abuse opioids worldwide. In this case report, we add to the literature the first reported homicide by intentional heroin administration in a 10-month old infant. Toxicology revealed morphine 1092ng/L, codeine 74ng/mL, and 6-monoacetyl-morphine 359ng/L in cardiac blood. Morphine 803ng/g, codeine 54ng/g in liver tissue, and morphine 181ng/mL was found in vitreous humor. With the prevalence of opioid abuse on the rise accidental opioid ingestions in the pediatric population have increased. However, forensic personnel must recognize the possibility of intentional poisoning in this vulnerable population.

Not just heroin: Extensive polysubstance use among US high school seniors who currently use heroin

BACKGROUND

Heroin-related deaths are on the rise in the US and a large portion of heroin overdoses involve co-use of other drugs such as benzodiazepines. A better understanding of heroin polysubstance use patterns could help discern better prevention measures.

METHODS

Data were examined from past-month ("current") heroin users from a nationally representative sample of high school seniors in the Monitoring the Future study (2010-2016, n = 327). We examined how past-month use and frequency of use of various drugs relate to frequency of current heroin use using chi-square and multivariable ordinal logistic regression.

RESULTS

Prevalence of any past-month use of various other drugs (and past-month use 10+ times) tends to increase as the frequency of heroin use increases; however, other drug use tends to decline among those reporting the use of heroin 40+ times in the past month. In multivariable models controlling for demographic characteristics, most levels of alcohol use were associated with decreased odds of higher-frequency heroin use (ps<.05). Nonmedical opioid (aOR = 5.84, p = .037) and tranquilizer (aOR = 14.63, p = .045) use 40+ times in the past month were associated with increased odds of higher-frequency heroin use.

CONCLUSIONS

High school seniors who use heroin also use multiple other drugs. Increases in the frequency of heroin use are associated with shifts in the nature and frequency of polysubstance use, with a higher frequency of heroin use associated with the highest percentage and frequency of use of depressants (nonmedical opioid and benzodiazepine use), compounding the risk of overdose. Prevention measures should consider polysubstance use patterns among heroin-using adolescents.

AH-7921: A review of previously published reports

AH-7921 is a synthetic opioid that was developed in the early 1970s. It has resulted in several fatal and nonfatal intoxications, despite not having approval from the US Food and Drug Administration. To date, AH-7921 is listed as a schedule I drug, and there have been no clinical trials exploring the safety of AH-7921. Herein, we provide an analysis of existing case reports available in the literature regarding AH-7921. We searched PubMed, Scopus, Web of Science, and EBSCO for articles (up until December 2017) using the terms "AH-7921" and "AH7921." In total, 48 articles were identified, and 5 articles were included in our review. A total of 14 cases were found, of which 13 resulted in fatalities. The oral route of administration was reported in two cases, and most cases reported use of concomitant pharmaceutical agents. Pulmonary edema was the most common finding postmortem among deceased cases, with nine of the cases having heavier lungs. Overall, fatalities occurred with low and high concentrations of AH-7921 in the femoral blood. We strongly encourage toxicology screenings for this novel opioid to be included when an overdose of an opioid of unknown nature is suggested.

Desensitization and Tolerance of Mu Opioid Receptors on Pontine Kölliker-Fuse Neurons

Acute desensitization of mu opioid receptors is thought to be an initial step in the development of tolerance to opioids. Given the resistance of the respiratory system to develop tolerance, desensitization of neurons in the Kölliker-Fuse (KF), a key area in the respiratory circuit, was examined. The activation of G protein-coupled inwardly rectifying potassium current was measured using whole-cell voltage-clamp recordings from KF and locus coeruleus (LC) neurons contained in acute rat brain slices. A saturating concentration of the opioid agonist [Met⁵]-enkephalin (ME) caused significantly less desensitization in KF neurons compared with LC neurons. In contrast to LC, desensitization in KF neurons was not enhanced by activation of protein kinase C or in slices from morphine-treated rats. Cellular tolerance to ME and morphine was also lacking in KF neurons from morphine-treated rats. The lack of cellular tolerance in KF neurons correlates with the relative lack of tolerance to the respiratory depressant effect of opioids.

Fatal and non-fatal opioid overdose in opioid dependent patients treated with methadone, buprenorphine or implant naltrexone

BACKGROUND

Illicit opioid use is associated with high rates of fatal and non-fatal opioid overdose. This study aims to compare rates of fatal and serious but non-fatal opioid overdose in opioid dependent patients treated with methadone, buprenorphine or implant naltrexone, and to identify risk factors for fatal opioid overdose.

METHODS

Opioid dependent patients treated with methadone (n=3515), buprenorphine (n=3250) or implant naltrexone (n=1461) in Western Australia for the first time between 2001 and 2010, were matched against state mortality and hospital data. Rates of fatal and non-fatal serious opioid overdoses were calculated and compared for the three treatments. Risk factors associated with fatal opioid overdose were examined using multivariate cox proportional hazard models.

RESULTS

No significant difference was observed between the three groups in terms of crude rates of fatal or non-fatal opioid overdoses. During the first 28days of treatment, rates of non-fatal opioid overdose were high in all three groups, as were fatal opioid overdoses in patients treated with methadone. However, no fatal opioid overdoses were observed in buprenorphine or naltrexone patients during this period. Following the first 28 days, buprenorphine was shown to be protective, particularly in terms of non-fatal opioid overdoses. After the cessation of treatment, rates of fatal and non-fatal opioid overdoses were similar between the groups, with the exception of lower rates of non-fatal opioid overdose in the naltrexone treated patients compared with the methadone treated patients. After the commencement of treatment, gender, and hospitalisations with a diagnosis of opioid poisoning, cardiovascular or mental health problems were significant predictors of subsequent fatal opioid overdose.

CONCLUSIONS

Rates of fatal and non-fatal opioid overdose were not significantly different in patients treated with methadone, buprenorphine or implant naltrexone. Gender and prior cause-specific hospitalisations can be used to identify patients at a high risk of fatal opioid overdose.

The Heroin Overdose Mystery

Heroin overdose deaths in the Unites States more than tripled from 2010 to 2014, reaching almost 11,000 per year. Despite the use of the term “overdose,” many of these victims died after self-administering an amount of opiate that would not be expected to be fatal for these drug-experienced, and drug-tolerant, individuals. Various explanations of this overdose mystery have been proposed. I describe an explanation based on Pavlovian conditioning. Organisms associate cues present at the time of drug administration with the systemic effect of the drug. These drug-predictive cues come to elicit responses that attenuate the effect of a drug. Such anticipatory conditional responses mediate chronic tolerance. If the drug is administered in the presence of novel cues, tolerance fails to occur and the victim suffers an overdose. Overdose prevention strategies should incorporate information about the contribution of drug-associated cues to drug tolerance.

The toxicology of heroin-related death: estimating survival times

BACKGROUND AND AIMS

The feasibility of intervention in heroin overdose is of clinical importance. The presence of 6-monoacetyl morphine (6MAM) in the blood is suggestive of survival times of less than 20-30 minutes following heroin administration. The study aimed to determine the proportions of cases in which 6MAM was present, and compare concentrations of secondary metabolites and circumstances of death by 6MAM status.

DESIGN

Analysis of cases of heroin-related death presenting to the Department of Forensic Medicine Sydney, 1 January 2013-12 December 2014.

SETTING

Sydney, Australia.

CASES

A total of 145 cases. The mean age was 40.5 years and 81% were male.

MEASUREMENTS

Concentrations of 6MAM, free morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). Circumstances of death included bronchopneumonia, apparent sudden collapse, location and other central nervous system (CNS) depressants.

FINDINGS

6MAM was detected in 43% [confidence interval (CI) = 35-51%] of cases. The median free morphine concentration of 6MAM-positive cases was more than twice that of cases without 6MAM (0.26 versus 0.12 mg/l). 6MAM-positive cases also had lower concentrations of the other major heroin metabolites: M3G (0.05 versus 0.29 mg/l), M6G (0.02 versus 0.05 mg/l) with correspondingly lower M3G/morphine (0.54 versus 2.71) and M6G/morphine (0.05 versus 0.50) ratios. Significant independent correlates of 6MAM were a higher free morphine concentration [odds ratio (OR) = 1.7], a lower M6G/free morphine ratio (OR = 0.5) and signs of apparent collapse (OR = 6.7).

CONCLUSIONS

In heroin-related deaths in Sydney, Australia during 2013 and 2014, 6- monoacetyl morphine was present in the blood in less than half of cases, suggesting that a minority of cases had survival times after overdose of less than 20-30 minutes. The toxicology of heroin metabolites and the circumstances of death were consistent with 6- monoacetyl morphine as a proxy for a more rapid death.

μ opioid receptor activation hyperpolarizes respiratory-controlling Kölliker-Fuse neurons and suppresses post-inspiratory drive

KEY POINTS

In addition to reductions in respiratory rate, opioids also cause aspiration and difficulty swallowing, indicating impairment of the upper airways. The Kölliker-Fuse (KF) maintains upper airway patency and a normal respiratory pattern. In this study, activation of μ opioid receptors in the KF reduced respiratory frequency and tidal volume in anaesthetized rats. Nerve recordings in an in situ preparation showed that activation of μ opioid receptors in the KF eliminated the post-inspiration phase of the respiratory cycle. In brain slices, μ opioid agonists hyperpolarized a distinct population (61%) of KF neurons by activation of an inwardly rectifying potassium conductance. These results suggest that KF neurons that are hyperpolarized by opioids could contribute to opioid-induced respiratory disturbances, particularly the impairment of upper airways.

ABSTRACT

Opioid-induced respiratory effects include aspiration and difficulty swallowing, suggesting impairment of the upper airways. The pontine Kölliker-Fuse nucleus (KF) controls upper airway patency and regulates respiration, in particular the inspiratory/expiratory phase transition. Given the importance of the KF in coordinating respiratory pattern, the mechanisms of μ opioid receptor activation in this nucleus were investigated at the systems and cellular level. In anaesthetized, vagi-intact rats, injection of opioid agonists DAMGO or [Met(5) ]enkephalin (ME) into the KF reduced respiratory frequency and amplitude. The μ opioid agonist DAMGO applied directly into the KF of the in situ arterially perfused working heart-brainstem preparation of rat resulted in robust apneusis (lengthened low amplitude inspiration due to loss of post-inspiratory drive) that was rapidly reversed by the opioid antagonist naloxone. In brain slice preparations, activation of μ opioid receptors on KF neurons hyperpolarized a distinct population (61%) of neurons. As expected, the opioid-induced hyperpolarization reduced the excitability of the neuron in response to either current injection or local application of glutamate. In voltage-clamp recordings the outward current produced by the opioid agonist ME was concentration dependent, reversed at the potassium equilibrium potential and was blocked by BaCl2 , characteristics of a G protein-coupled inwardly rectifying potassium (GIRK) conductance. The clinically used drug morphine produced an outward current in KF neurons with similar potency to morphine-mediated currents in locus coeruleus brain slice preparations. Thus, the population of KF neurons that are hyperpolarized by μ opioid agonists are likely mediators of the opioid-induced loss of post-inspiration and induction of apneusis.

The pharmacology of medieval sedatives: the "Great Rest" of the Antidotarium Nicolai

ETHNOPHARMACOLOGICAL RELEVANCE

Past practices of compound drugs from different plant ingredients enjoyed remarkable longevity over centuries yet are largely dismissed by modern science as subtherapeutic, lethal or fanciful.

AIM OF THE STUDY

To examine the phytochemical content of a popular medieval opiate drug called the "Great Rest" and gauge the bioavailability and combined effects of its alkaloid compounds (morphine, codeine, hyoscyamine, scopolamine) on the human body according to modern pharmacokinetic and pharmacodynamic parameters established for these compounds.

CALCULATIONS AND THEORY

We reviewed the most recent studies on the pharmacodynamics of morphine, codeine, hyoscyamine and scopolamine to ascertain plasma concentrations required for different physiological effects and applied these findings to dosage of the Great Rest.

RESULTS

Given the proportional quantities of the alkaloid rich plants, we calculate the optimal dose of Great Rest to be 3.1±0.1-5.3±0.76 g and reveal that the lethal dose of Great Rest is double the therapeutic concentration where all three alkaloid compounds are biologically active.

CONCLUSION

This study helps establish the effective dose (ED50), toxic dose (TD50) and lethal dose (LD50) rates for the ingestion of raw opium, henbane and mandrake, and describes their probable combined effects, which may be applied to similar types of pre-modern pharmaceuticals to reveal the empirical logic behind past practices.

Drug poisoning deaths in Sweden show a predominance of ethanol in mono-intoxications, adverse drug-alcohol interactions and poly-drug use

Over a 10-year period (1998-2007) all deaths in Sweden classified by forensic pathologists as fatal drug poisonings (N = 6894) were retrieved from a toxicology database (TOXBASE) belonging to the National Board of Forensic Medicine. The deaths were further classified as suicides N = 2288 (33%), undetermined N = 2260 (33%) and accidental N = 2346 (34%). The average age (± SD) of all victims was 49.1 ± 15.9 years and men 47.4 ± 15.6 years were 5-year younger than women 52.2 ± 15.8 years (p < 0.01). Most of the deceased (78%) were poly-drug users although a single drug (mono-intoxications) was found in 22% of all poisoning deaths (p < 0.001). The number of drugs in blood samples varied from 1 to 12 with a median of 3-4 per case. Mono-intoxication deaths were mostly ethanol-related (N = 976) and the mean and median blood-alcohol concentration (BAC) was 3.06 g/L and 3.10 g/L, respectively. The BAC decreased as the number of additional drugs in blood increased from 2.15 g/L with one drug to 1.25 g/L with 6 or more drugs. The mean (median) concentrations of non-alcohol drugs in mono-intoxication deaths were morphine (N = 93) 0.5mg/L (0.2mg/L), amphetamine (N = 39) 2.0mg/L (1.2mg/L), dextropropoxyphene (N = 33) 3.9 mg/L (2.9 mg/L), dihydro-propiomazine (N = 32) 1.6 mg/L (1.0mg/L) and 7-amino-flunitrazepam (N = 28), 0.4 mg/L (0.3mg/L). Elevated blood morphine in these poisoning deaths mostly reflected abuse of heroin as verified by finding 6-monoacetyl morphine (6-MAM) in the blood samples. When investigating drug poisoning deaths a comprehensive toxicological analysis is essential although the results do not reveal the extent of prior exposure to drugs or the development of pharmacological tolerance. The concentrations of drugs determined in post-mortem blood are one element in the case. The autopsy report, the police investigation, the findings at the scene and eye-witness statements should all be carefully considered when the cause and manner of death are determined.

Toxicological analysis in rats subjected to heroin and morphine overdose

In heroin overdose deaths the blood morphine concentration varies substantially. To explore possible pharmacokinetic explanations for variable sensitivity to opiate toxicity we studied mortality and drug concentrations in male Sprague-Dawley rats. Groups of rats were injected intravenously (i.v.) with heroin, 21.5 mg/kg, or morphine, 223 mg/kg, causing a 60-80% mortality among drug-naïve rats. Additional groups of rats were pre-treated with morphine for 14 days, with or without 1 week of subsequent abstinence. Brain, lung and blood samples were analyzed for 6-acetylmorphine, morphine, morphine-3-glucuronide and morphine-6-glucuronide. i.v. morphine administration to drug-naïve rats resulted in both rapid and delayed deaths. The brain morphine concentration conformed to an exponential elimination curve in all samples, ruling out accumulation of morphine as an explanation for delayed deaths. This study found no support for formation of toxic concentration of morphine-6-glucuronide. Spontaneous death among both heroin and morphine rats occurred at fairly uniform brain morphine concentrations. Morphine pre-treatment significantly reduced mortality upon i.v. morphine injection, but the protective effect was less evident upon i.v. heroin challenge. The morphine pre-treatment still afforded some protection after 1 week of abstinence among rats receiving i.v. morphine, whereas rats given i.v. heroin showed similar death rate as drug-naïve rats.

Increased vulnerability of ApoE4 neurons to HIV proteins and opiates: protection by diosgenin and L-deprenyl

Human immunodeficiency virus (HIV) infection continues to rise in drug-abusing populations and causes a dementing illness in a subset of individuals. Factors contributing to the development of dementia in this population remain unknown. We found that HIV-infected individuals with the E4 allele of Apolipoprotein E (ApoE) or history of intravenous drug abuse had increased oxidative stress in the CNS. In vitro studies showed that HIV proteins, gp120 and Tat, Tat + morphine but not tumor necrosis factor-alpha (TNF-alpha), caused increased neurotoxicity in human neuronal cultures with ApoE4 allele. Microarray analysis showed a differential alteration of transcripts involved in energy metabolism in cultures of ApoE3 and 4 neurons upon treatment with Tat + morphine. This was confirmed using assays of mitochondrial function and exposure of the neurons to Tat + morphine. Using this in vitro model, we screened a number of novel antioxidants and found that only L-deprenyl and diosgenin protected against the neurotoxicity of Tat + morphine. Furthermore, Tat-induced oxidative stress impaired morphine metabolism which could also be prevented by diosgenin. In conclusion, opiate abusers with HIV infection and the ApoE4 allele may be at increased risk of developing dementia. L-deprenyl and a plant estrogen, diosgenin, may have therapeutic potential in this population.

Evaluation of the role of abstinence in heroin overdose deaths using segmental hair analysis

In the body heroin is rapidly metabolized to 6-acetylmorphine and morphine. Victims of lethal heroin overdose often present with fairly low blood concentrations of morphine. Reduced tolerance due to abstinence has been proposed to account for this finding. The aim of the present study was to examine the role of abstinence in drug-related deaths by comparing recent and past exposure to opioids using segmental hair analysis with the postmortem blood morphine concentrations in deceased heroin users. The study included 60 deceased drug addicts in the Stockholm area, Sweden. In 32 cases, death was not related to heroin intake. In 18 of the 28 heroin fatalities, opioids were absent in the most recent hair segment, suggesting a reduced tolerance to opioids. However, the blood morphine levels were similar to those found in the 10 subjects that showed continuous opioid use. Hair and blood analysis disclosed an extensive use of additional drugs that directly or indirectly may influence the opioid system. The results suggest that abstinence is not a critical factor for heroin overdose death. Obviously tolerant subjects die after intake of similar doses. Other factors, particularly polydrug use, seem to be more causally important for these deaths.

Comparison of acute lethal toxicity of commonly abused psychoactive substances

AIMS

To determine the acute lethal toxicity of a range of psychoactive substances in terms of the dose customarily used as a single substance for non-medical purposes.

DESIGN AND METHOD

A structured English-language literature search was conducted to identify experimental studies and clinical reports that documented human and non-human lethal doses of 20 abused substances that are distributed widely in Europe and North America. Four inclusion criteria were specified for the reports, and approximately 3000 relevant records were retrieved from search engines at Biosis, Science Citation Index, Google and the National Library of Medicine's Gateway. In order to account for different drug potencies, a 'safety ratio' was computed for each substance by comparing its reported acute lethal dose with the dose most commonly used for non-medical purposes.

FINDINGS

The majority of published reports of acute lethal toxicity indicate that the decedent used a co-intoxicant (most often alcohol). The calculated safety ratios varied between substances by more than a factor of 100. Intravenous heroin appeared to have the greatest direct physiological toxicity; several hallucinogens appeared to have the least direct physiological toxicity.

CONCLUSIONS

Despite residual uncertainties, the substantial difference in safety ratios suggests that abused substances can be rank-ordered on the basis of their potential acute lethality.

Endogenous opiates and behavior: 2002

This paper is the twenty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2002 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).