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While many other drugs get national attention, a significant number of people still die from heroin overdose.
Doctors and the general public could be forgiven for assuming that the “heroin problem” is no longer with us. In recent years, the focus of the media has been squarely on drugs such as methamphetamine, cocaine, and 3,4‐methylenedioxymethamphetamine (MDMA; also known as ecstasy) (here). While these are clearly worthy of serious discussion, little recent attention has been given to heroin.
Just because one drug comes to prominence does not mean that another ceases to be a problem. Indeed, it is estimated that some 55 700 people were enrolled in opioid agonist treatment (buprenorphine or methadone) on a given day in 2022 (here), mainly for the management of heroin dependence, demonstrating its ongoing relevance as a public health issue. Moreover, the rate of heroin overdose deaths has been rising over past decade (here).
Examining heroin overdose fatalities
Alongside the personal and societal costs of heroin dependence, there are good reasons to examine the characteristics and circumstances of fatalities from heroin overdose in the 2020s.
Polypharmacy is a cardinal feature of heroin overdose (here), particularly where there is use of multiple ventral nervous system depressants, such as benzodiazepines and other hypnosedatives.
Even though to date we have not seen increases in the use of pharmaceutical opioids such as oxycodone and fentanyl on the scale observed in North America (here), the use of these drugs has become more common and may substantially increase the risk of an overdose when used with heroin.
In recent years, there have also been major increases globally in the use of psychostimulants, most notably methamphetamine and cocaine (here). The use of psychostimulants, which are drugs that increase myocardial oxygen demand in tandem with heroin (a drug that reduces oxygenation), may well increase the risk of cardiorespiratory arrest.
The toxicology of fatal heroin overdose may also provide clues as to survival times following the final administration of heroin, which has implications for the feasibility of intervention. The presence of the morphine metabolite 6-acetyl morphine (6-AM) in post mortem blood suggests that the individual survived less than 20–30 minutes after the dose, while its absence suggests that there was a longer survival time (here), thus with potential for intervention to have been received in that window.
Our recent study
In our recent study, we examined all cases of heroin toxicity deaths in Australia in 2020–2022 retrieved from the National Coronial Information System — a database of medicolegal death investigation records provided by the coroners’ courts in each Australian and New Zealand jurisdiction (here).
We found that 610 people died of heroin overdose in those years. Beyond question, heroin remains a significant problem. Who were these people? The average age was 43 years but ranged into the 70s. We are seeing far more older people dying of heroin overdose that when we first studied overdose in the 1990s, when the oldest people were aged in their 50s (here). Most were men (80.5%), and only 7.5% were in a treatment program for their heroin dependence. The median free morphine concentration was 0.17 mg/L, with the highest concentrations being 25 times that of the median.
Although there were high concentrations, the skew was towards lower concentrations, with a third in the ≤ 0.10 mg/L range. Given the range, it is not possible to set a limit for a morphine concentration that defines a heroin overdose. Even in low doses death may occur, especially when injected intravenously, and severe respiratory impairment may persist long after the peak blood morphine concentration has passed.
As we have seen across decades, almost all cases (95.2%) involved heroin being used with other drugs, most commonly hypnosedatives such as diazepam. Other opioids were seen in a fifth of cases, but drugs such as fentanyl and oxycodone were detected in approximately 2% of cases. Psychostimulants, most commonly methamphetamine, were present in 44.8% of cases. This represents a major shift in the toxicology of heroin overdose, as in earlier years fewer than 10% of cases were positive for psychostimulants.
Most importantly, using the toxicology results we were able to make an estimate of survival times. We estimated that in over half of cases there had been a survival time in excess of 20–30 minutes after the dose, with 6-AM present in the blood of 47.0% of cases.
What can be done?
Each of these deaths is a tragedy and we must learn from them to reduce the number of such cases. We know that enrolment in a treatment program substantially reduces the risk of overdose and death. The more people with heroin dependence who we enrol in treatment, the more lives are likely to be saved.
Even though after years of information campaigns many people who use heroin will be aware of the dangers of poly-depressant use, it is less likely that they are aware of the potential role of psychostimulants. Making sure take-home naloxone, the antidote to a heroin overdose, is available to heroin users (indeed to all users of opioids and potential witnesses) is crucial. Any Australian who may be at risk of experiencing or witnessing an opioid overdose can access naloxone for free over the counter through the national Take Home Naloxone program.
Nasal preparations are now available so the individual administering the antidote does not need to know how to inject a person (here). In most cases, there is ample time to intervene. Even so, people present should always call an ambulance when a person has overdosed. Finally, we might consider the use of wearable technology, widely used with older people. These potentially life-saving medical devices might be used to detect and initiate responses to overdose.
Summary
It is clear that heroin has not gone away, although the toxicology of overdose has changed, with significant numbers of people continuing to die from the effects of heroin. We must keep this in mind, and not be distracted by the attention given to other drugs.
Shane Darke is a Professor at the National Drug and Alcohol Research Centre, University of New South Wales.
Johan Duflou is a Clinical Professor at the Sydney Medical School, University of Sydney.
Amy Peacock is Associate Professor at the National Drug and Alcohol Research Centre, University of New South Wales.
Michael Farrell is Director of the National Drug & Alcohol Research Centre University of New South Wales.
Julia Lappin is a Associate Professor at the Discipline of Psychiatry and Mental Health, University of New South Wales.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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