Heroin Toxicity

Article Author:
Robert Oelhaf
Article Editor:
Mohammadreza Azadfard
Updated:
11/8/2018 8:24:06 PM
PubMed Link:
Heroin Toxicity

Introduction

Heroin, also known as diacetylmorphine, is a very strong opioid.  Many deaths each year are caused by heroin overdoses throughout the world. It is one of the most commonly used drugs among intravenous drug abusers. Conventionally, chemical compounds that are fractionated from the juice of the opium poppy (Papaver somniferum) are known as opiates. Similarly acting synthetic chemical compounds are known as opioids. Heroin is derived by acetylation of morphine, the predominant opiate found in opium poppy juice.

Etiology

Heroin is usually used as an illegal drug of abuse. In rare settings, heroin is prescribed by doctors for pain control. Heroin is not allowed to be prescribed by doctors in the United States, but prescription heroin is available in rare settings in other countries. 

Epidemiology

Because of various economic and social factors, heroin is one of the most commonly abused opioids in the world today. The juice of the opium poppy is harvested, which contains a variety of opiates, mostly morphine. Additional processing is necessary to refine the opium poppy liquid into heroin, which involves acetylation of morphine to diacetylmorphine, or heroin. Heroin is smaller per dose, making it the version of the product preferred by drug smugglers. 

Pathophysiology

Heroin has effects on the opioid receptors, particularly the mu receptor, where it generates pain control, respiratory depression, and euphoria. It also has effects on the kappa and delta receptors. Kappa receptors are associated with dysphoria, dissociation, and hallucinations. Delta receptors are less well characterized but are thought to influence mood. There is an evolving body of knowledge that the intensity and quality of response to heroin and other opioids can vary significantly between patients which can be unrelated to tolerance.

Toxicokinetics

Heroin is a strong agonist of opioid receptors. Its half-life is around eight hours, requiring drug abusers to use it several times per day to maintain the effect. Additionally, tolerance usually develops over time, requiring consumers to take stronger and stronger doses to get the same effect. Overdose is common as a consumer often does not know how much they are taking per purchased dose. Also, in street drugs, there are often contaminants that dilute the percentage of the drug consumed.

History and Physical

Heroin's half-life is so short that consumers are usually seen medically in the setting of either overdose or withdrawal. In the overdose setting, there is usually decreased respiratory effort and rate, with sedation and constricted pupils. A severe overdose can progress to apnea with coma, which is followed by minutes by cardiac arrest and death unless immediate rescue measures are taken. Heroin withdrawal is often associated with alertness, hostility, dilated pupils, piloerection, sweating, vomiting, diarrhea and yawning. Some or all of these symptoms may be seen; the patient does not need all to be diagnosed with heroin withdrawal. If there is intravenous use, there can be "track marks." These are very small abrasion type skin changes overlying veins, usually in the extremities, but infrequently can also be found in the neck and other anatomic locations. Intravenous drug use can lead to infectious complications that are discussed elsewhere (such as cellulitis, thrombophlebitis, endocarditis, septic emboli and compartment syndrome for example). Adulterants in heroin can be quite diverse and sometimes unknown to the consumer and can confound the evaluator by giving a potentially very broad spectrum of conflicting physical exam findings. Law enforcement may have knowledge of the current adulterant blend of the heroin that is being locally consumed at the time of the encounter.

Evaluation

The evaluation is clinical, with prioritization of airway and breathing in the overdose setting. Urine drug screening is thought to not be useful in the acute setting but has value in surveillance (employment screening) or recovery (drug rehab) setting. On urine drug testing, heroin makes the "opioids" line positive, along with morphine, codeine, hydromorphone, and hydrocodone. Other opioids usually do not turn this test positive and need to be tested for separately, including methadone, oxycodone, fentanyl, buprenorphine, and tramadol. Bedside/office urine cup drug screens have (infrequent) false positive and false negative results for a variety of substances tested for. Gas chromatography and mass spectroscopy (GCMS) testing can be used for a definitive answer if there is a conflict between the patient and the provider regarding the truth or falsehood of the urine drug test result. Medical Review Officers control the information obtained during employment-related drug testing in the United States.

Treatment / Management

In the heroin overdose setting, hypopnea (breathing that is ineffectively slow and/or shallow) can progress to apnea. Naloxone is a mainstay of therapy in this setting, but the practitioner is warned that first line treatment is control of the airway and rescue breathing. Bag valve mask ventilation or similar intervention should be initiated immediately by the primary rescuer to restore oxygen supply to vital organs while other rescuers evaluate available methods of naloxone administration. A single rescuer should focus on providing oxygen to the overdose victim until other rescuers are available to assist. Basic Life Support and Advanced Cardiac Life Support principles should be followed during the resuscitation of a heroin overdose.

Pearls and Other Issues

Heroin use, abuse, overdose, and addiction have had many discussions in the professional and lay press of the United States, which intensified in the 2000s and 2010s. After around 2012 the United States government began to shift prioritization of money from interdiction and law enforcement to treatment programs to treat drug addicts including those addicted to heroin. This focus shift was brought about by several factors. One factor was a growing recognition that interdiction efforts, in what was known commonly as the drug war, were not yielding results equivalent to the effort and money invested. There was also growing professional, and lay acceptance of the concept of medication assisted treatment, involving replacing the heroin with another opioid such as methadone or buprenorphine. A growing body of evidence began to show more clearly that medication assisted treatment when added to traditional abstinence efforts suppressed relapse risk more effectively than abstinence efforts alone. As of 2016, there was ongoing sometimes heated debate regarding if medication assisted treatment was exchanging one drug for another, as was asserted by some addiction treatment leaders of the time, and if that were true, what ethical ramifications that presented to the practitioner. The trend of consensus, where that could be obtained, was that the benefits of harm reduction with the initiation of medication assisted treatment outweighed the risks in someone verified to be a patient with recurrent, problematic, accelerating use of opioids.