Elsevier

The Lancet

Volume 351, Issue 9120, 27 June 1998, Pages 1923-1925
The Lancet

Early Report
Death from heroin overdose: findings from hair analysis

https://doi.org/10.1016/S0140-6736(97)10101-5Get rights and content

Summary

Background

Morphine analysis of hair is used in forensic toxicology to study the addiction history of heroin addicts. To clarify the features underlying fatal heroin intake, we measured hair morphine content in a group of deceased heroin addicts, to verify a possible correlation between fatal heroin overdoses and the addiction behaviour of these individuals before death.

Methods

91 deaths were attributed to heroin overdose in Verona, Italy, in 1993-96. We analysed the hair of 37 of these individuals, and of 37 active heroin addicts, 37 former heroin users abstinent from the drug for several months, and 20 individuals with no evidence of exposure to opioids. From each individual, a hair sample of about 150 mg was analysed by RIA and high-performance liquid chromatography, to measure the morphine content.

Findings

The mean morphine content in the hair of the addicts who had died was 1·15 ng/mg (SD 2·35 ng/mg; range 0–12·25 ng/mg) compared with 6·07 ng/mg (4·29; 1·15–17·0) in the active heroin addicts, 0·74 ng/mg (0·93; 0·10–3·32) in the abstinent former addicts, and values below the detection limit in the non-exposed group. Hair morphine content among those who had died was significantly lower than that in active heroin consumers (p<0·0001), but not significantly different from that in the former addicts (p=0·978).

Interpretation

Although our findings may be subject to selection bias, since suitable hair samples were available for only 37 of the 91 addicts who had died, these findings support the theory of high susceptibility to opioid overdose after periods of intentional or unintentional abstinence, due to loss of tolerance. Medical staff running detoxification programmes should be aware of the risk inherent in relapse to heroin after a period of abstinence. Moreover, occasional heroin use without a build-up of tolerance could also give a high risk of overdose.

Introduction

In Italy, according to official epidemiological data, heroin overdoses account for about 1000 deaths per year.1 Despite the efforts of forensic pathologists, clinical pathologists, and toxicologists, the mechanisms by which heroin overdose leads to death are not yet clear. A major reason for the lack of clarification is that blood samples taken from people who have died from heroin overdose show great variation in the amounts of biologically active metabolites of heroin present. Even in cases of acute overdose, observed blood concentrations of morphine, the main active metabolite of heroin, have ranged from 10 ng/mL to 4000 ng/mL.2, 3 This range hampers the definition of a clear threshold of lethal heroin intake. The range can be partly ascribed to variable survival times after heroin injection,4, 5, 6 which in most cases are unknown, and to the rapid disappearance of heroin and its active metabolites from the blood (half-life heroin, 9 min; 6-acetylmorphine, 38 min; morphine, 80 min2). Thus, even though the blood concentrations fall, morphine bound to receptors in the central nervous system may lead to death by respiratory failure.7

Respiratory depression caused by opioids is the main physiological explanation of fatal heroin overdoses, but other explanations include metabolic variation in heroin tolerance,8, 9 the toxicity of adulterants,10 pharmacological interactions with alcohol,11 and even allergic reaction to components of heroin preparations.12 However, the relevance of these factors in explaining the majority of deaths has not been statistically proved. Moreover, investigation of the mechanisms of fatal heroin overdose is hindered by gaps in individual case histories. Any information given by relatives and friends concerning the medical history of the victim is likely to be unreliable because of the addict's lifestyle and environment.

To address this issue, toxicological analysis of hair can be used in the retrospective investigation of drug use and addiction. Head hair grows at approximately 0·8–1·3 cm per month.13 Drugs can be detected in hair tissue weeks or months after intake. Exogenous compounds are incorporated into hair tissue at the root. They reach the growing hair matrix from capillary blood surrounding the hair germination centre, from skin-gland secretions,14 and, in some cases, from the external environment.15 The low metabolic activity of the hair shaft, and the protection exerted by the hair matrix components, contribute to the stability of the embedded compounds. Although contamination of the hair by drugs present in the environment,16 by hair bleaching, and by hair dyeing17 may affect the accumulation of chemicals in the hair matrix, there is consensus about the usefulness of hair analysis in the study of prevalence of drugs misuse.18

On these grounds, we used hair analysis, in addition to the usual forensic tests of biological fluids, to study heroinlinked deaths in the province of Verona, Italy. We aimed to verify a possible correlation between these deaths, and the drug use of the individual in the months before death.

Section snippets

Methods

From among 91 heroin-related deaths between 1993 and 1996, we selected 37 individuals (29 men, eight women, aged 18–34) for hair analysis (group D). Criteria for selection were availability of hair, state of decomposition, lack of contamination of hair (blood, vomit, etc), lack of cosmetic treatments, availability of devices to sample hair during necropsy, and collaboration of the necropsy technicians. All the cases underwent our routine pathological and toxicological analysis. Urine was

Results

All urine samples from group A1 were positive for opioids. The urine samples from group A2 tested negative for all substances. All members of group D tested positive for opioids in urine. Benzodiazepines, alcohol, cannabinoids, amphetamines, and methadone were also found in the urine samples from several members of group D, but there was no specific pattern. Group N was not tested by urinalysis, because this information was not relevant for our purposes, and because toxicological urinalyses of

Discussion

The link between drug use and drug accumulation in hair has been examined in several earlier reports.23, 24, 25, 26 To our knowledge, however, hair analysis has not been used to investigate the recent addiction histories of people who have died from heroin overdose. Our study was limited to the province of Verona, and may have been subject to selection bias since suitable hair samples were available for only 37 of the 91 addicts who died. However, we have shown that most fatal heroin overdoses

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