What does heroin do
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Understanding the Effects of Heroin
Introduction to Heroin and Its Use
Heroin, also known as diacetylmorphine, is an opioid derived from morphine. It was initially synthesized by the Bayer Company in 1889 as a less addictive substitute for morphine, but it has since become a major public health issue due to its high potential for addiction and overdose1. Heroin use has surged in recent years, leading to significant increases in emergency department visits and fatalities1.
Pharmacology of Heroin
Mechanism of Action
Heroin exerts its effects by acting as an agonist on the mu, kappa, and delta receptors in the central nervous system. The mu1 receptors are primarily responsible for analgesic effects, while mu2 receptors contribute to respiratory depression, euphoria, and physical dependence1. Heroin is rapidly absorbed and crosses the blood-brain barrier within seconds, leading to a quick onset of effects1.
Metabolism
Once in the brain, heroin is metabolized to monoacetylmorphine and then to morphine, which further interacts with opioid receptors to produce its effects1. This rapid metabolism and high lipid solubility contribute to the intense "rush" experienced by users and the high potential for toxicity1.
Acute Effects on Emotions
Heroin administration in dependent individuals leads to a significant decrease in negative emotions such as anxiety and depression, and an increase in positive emotions and overall emotional well-being2. This emotional regulation underscores the clinical benefits of opioid substitution treatments for managing heroin dependence2.
Long-term Effects and Dependence
Mortality and Overdose
Regular heroin users face a high risk of overdose, with an average annual mortality rate of 2%, which is significantly higher than that of non-drug-using peers1. Overdoses are primarily due to respiratory depression caused by the drug's action on the brainstem respiratory centers1.
Health and Social Implications
Heroin dependence is associated with a wide range of health issues, including infectious diseases, psychiatric comorbidities, and social problems such as criminal activity and unemployment4. The combination of heroin with other substances like alcohol or benzodiazepines further increases the risk of fatal outcomes1.
Neurochemical Effects
Dopamine and Reinforcement
Heroin's reinforcing effects are linked to its action on the dopaminergic system. Studies have shown that heroin increases dopamine concentrations in the nucleus accumbens, a brain region associated with reward and reinforcement5 6 7. This increase in dopamine is a key factor in the drug's addictive potential.
Disinhibition of Dopamine Neurons
Heroin activates dopamine neurons in the ventral tegmental area (VTA) that project to the nucleus accumbens, reinforcing drug-taking behavior6. Inhibition of these dopamine neurons has been shown to block heroin self-administration, highlighting the critical role of the dopaminergic system in heroin addiction6.
Treatment Approaches
Pharmacological Treatments
Several pharmacological treatments are available for managing heroin dependence, including methadone, buprenorphine, and levo-alpha-acetylmethadol (LAAM)3 4. These treatments help stabilize patients, reduce illicit drug use, and improve health and social functioning3.
Heroin Maintenance Therapy
Heroin maintenance therapy, where heroin is prescribed alongside methadone, has shown promise for treatment-refractory patients. This approach helps retain patients in treatment, reduces illicit drug use, and improves social functioning, although it carries a higher risk of adverse events3 8 10.
Conclusion
Heroin is a potent opioid with significant effects on the central nervous system, leading to both acute euphoria and long-term dependence. Its impact on the dopaminergic system underlies its high potential for addiction. Effective management of heroin dependence requires a combination of pharmacological treatments and comprehensive care to address the wide range of health and social issues associated with its use.
Sources and full results
Most relevant research papers on this topic
Acute Heroin Overdose
Heroin overdoses are a significant public health issue, with a 2% annual mortality rate in regular heroin users, and naloxone is crucial for treating and preventing complications.
Systematic Review
Highly CitedAcute effects of heroin on emotions in heroin-dependent patients.
Heroin administration reduces negative emotions and cravings in heroin-dependent patients, increasing positive emotions, highlighting the clinical benefit of opioid substitution treatment.
RCTHeroin maintenance for chronic heroin-dependent individuals.
Heroin maintenance combined with flexible doses of methadone can reduce illicit substance use, criminal activity, and incarceration, potentially reducing mortality, but has a higher risk of serious adverse events.
Systematic Review
Very Rigorous JournalHighly CitedPharmacologic Treatment of Heroin-Dependent Patients
Pharmacologically based treatments show promise for expanding treatment options for heroin-dependent patients, with internists potentially playing a direct role in providing drug treatment services in their offices.
Systematic ReviewHighly CitedThe effects of intravenous heroin administration on extracellular nucleus accumbens dopamine concentrations as determined by in vivo microdialysis.
Heroin self-administration does not show a significant increase in dopamine levels in the nucleus accumbens, contradicting the hypothesis that dopamine plays a critical role in heroin self-administration.
RCT
Animal StudyHighly CitedDopamine neurons projecting to medial shell of the nucleus accumbens drive heroin reinforcement
Heroin reinforcement is driven by activating dopamine neurons in the medial part of the ventral tegmental area, specifically projecting to the medial shell of the nucleus accumbens.
Rigorous JournalHighly CitedHeroin reward is dependent on a dopaminergic substrate.
Heroin reward is dependent on a dopaminergic substrate, supporting the notion that opiates and other sources of reward activate a similar neural substrate.
Non-RCTAnimal StudyHighly CitedPrescription of Heroin for the Management of Heroin Dependence
Heroin treatment for heroin dependence shows comparable retention, improved health, and reduced illicit use compared to oral methadone treatment, with potential cost-effectiveness and savings in the criminal justice sector.
Literature ReviewPharmacological treatments for heroin and cocaine addiction
Heroin addiction treatment focuses on crisis intervention, detoxification, stabilization, and harm reduction, while cocaine addiction relies on cognitive behavior therapies and contingency management strategies.
Systematic ReviewScience and politics of heroin prescription
Prescribed heroin injections show increased reductions in illicit heroin use and treatment retention compared to injectable and oral methadone, but implementation faces challenges due to special interests and politics.
Rigorous Journal