This articlecontainsinstructions or advice. Wikipedia is not a guidebook; please helprewrite such content to be encyclopedic or move it toWikiversity,Wikibooks, orWikivoyage.(July 2025)

Opioid overdose
Other names	Narcotic overdose, opioid poisoning
A naloxone kit distributed in British Columbia, Canada
Specialty	Toxicology,emergency medicine
Symptoms	Respiratory depression,small pupils,unconsciousness
Complications	Permanent brain damage
Causes	Opioids (morphine,codeine,heroin,fentanyl,tramadol,methadone, etc.)
Risk factors	Opioid dependence, metabolic disorders, use of high doses of opioids, injection of opioids, use withantidepressants,alcohol,benzodiazepines, andcocaine.[1][2]
Diagnostic method	Based on symptoms[3]
Differential diagnosis	Low blood sugar,alcohol intoxication,head trauma,stroke[4]
Prevention	Improved access tonaloxone, treatment of opioid dependence
Treatment	Supporting a person's breathing andnaloxone
Deaths	over 110,000 (2017)

Anopioid overdose istoxicity due to excessive consumption ofopioids, such asmorphine,codeine,heroin,fentanyl,tramadol, andmethadone.^[3][5] This preventable pathology can be fatal if it leads torespiratory depression, a lethal condition that can causehypoxia from slow and shallow breathing.^[3] Other symptoms includesmall pupils^{[note 1]} andunconsciousness; however, its onset can depend on the method of ingestion, the dosage and individual risk factors.^[6] Although there were over 110,000 deaths in 2017 due to opioids, individuals who survived also faced adverse complications, includingpermanent brain damage.^[7][8]

Opioid overdoses are diagnosed based on symptoms and examination.^[3] Risk factors for opioid overdose include high levels ofopioid dependence, use of opioids via injection, high-dose opioid usage, having amental disorder or having a predisposition for one, and use of opioids in combination with other substances, such asalcohol,benzodiazepines, orcocaine.^[1][9][2] Dependence on prescription opioids can occur from their use to treatchronic pain in individuals.^[1] Additionally, if following a period ofdetoxification, which allows the tolerance level to fall, the risk of overdose upon return to use is high.^[1]

Initial treatment of an overdose involves supporting the person's breathing and providingoxygen to reduce the risk ofhypoxia.^[10]Naloxone is then recommended to those who cannot reverse the opioid's effects through breathing.^[10][3] Giving naloxone vianasal administration or as aninjection into a muscle has shown to be equally effective.^[11] Other efforts to prevent deaths from overdose include increasing access to naloxone andtreatment for opioid dependence.^[1][12]

Drug use contributes to 500,000 deaths worldwide, with opioid overdose resulting in approximately 115,000 of these deaths in 2018.^[1] This is up from 18,000 deaths in 1990.^[13][14] In 2018, approximately 269 million people had engaged in drug usage at least once, 58 million of which used opioids.^[1] Drug use disorders have affected around 35.6 million people worldwide in 2018.^[1] TheWHO estimates that 70% of deaths due to drug use are in relation to opioids, with 30% being due to overdose.^[1] It is believed that theopioid epidemic has partly been caused due to assurances that prescription opioids were safe, by thepharmaceutical industry in the 1990s.^[15] This led to unwarranted trust and a subsequent heavy reliance on opioids.^[15] Though there are treatment interventions which can effectively reduce the risk of overdose in people with opioid dependence, less than 10% of affected individuals receive it.^[1]

Opiate overdose symptoms and signs can be referred to as the "opioidtoxidrome triad": decreased level of consciousness,pinpoint pupils, andrespiratory depression. Other signs and symptoms includeseizures andmuscle spasms. Sometimes, an opiate overdose can lead to such a decreased level of consciousness that the person will not wake up.

Because of their effect on the part of the brain that regulates breathing,opioids can cause very slow or stopped breathing during overdoses, leading tohypoxia^[16] or death if left untreated.^[1] Hypoxia is typically caused by respiratory depression.^[17][18] The brain uses oxygen to regulate thehomeostasis of the body. In animal studies, it was found that opioids act on specific regions of thecentral nervous system associated with respiratory regulation, including themedulla andpons.^[18] During cerebral hypoxia, the brain lacks sufficient oxygen supply.^[17] Prolongedlack of oxygenation fromrespiratory depression can lead to detrimental damage to the brain and spinal cord and can leave the person unable to walk or function normally, even if treatment with naloxone is given.^[17]

Alcohol also causes respiratory depression and, therefore, when taken with opioids, can increase the risk ofrespiratory depression and death.^[1]

In young children, opioid overdose may not be apparent right away. This is due to absorption, distribution, and metabolism differences between young children and adults and the higher amount of opioid ingestion per kilogram of body weight.^[3]

Risk factors for opioid overdose includeopioid dependence, injecting opioids, using high doses of opioids, and use together withalcohol,benzodiazepines, orcocaine.^[1][2] The risk is particularly high followingdetoxification.^[1] Dependence on prescription opioids can occur from their use to treatchronic pain.^[1] In young children, an overdose is usually due to opioids that are intended for their parents, older siblings, or grandparents.^[20] In mothers who takecodeine during breastfeeding, opioid overdoses have occurred in their baby.^[21] Codeine is, therefore, not recommended for those who are breastfeeding.^[21]

Opioid overdoses are often associated withbenzodiazepines,tranquilisers (e.g.xylazine) oralcohol use.^[22][23] Other central nervous system depressants, muscle relaxers, pain relievers, anti-convulsants,anxiolytics, treatment drugs of a psychoactive or epileptic variety or any other such drug with its active function meant to calm or mitigate neuronal signaling (barbiturates, etc.) can additionally cause a worsened condition with less likelihood of recovery cumulative to each added drug. This includes drugs less immediately classed to a slowing of the metabolism such as with GABAergic likeGHB or glutamatergic antagonists likePCP orketamine.

End organ dysfunction (liver disease), which may lead to decreased drug clearance, is a risk factor for opioid overdose.^[24] Other risk factors for opioid overdose includesleep disordered breathing disorders such assleep apnea, pulmonary diseases (such asasthma orchronic obstructive pulmonary disease) which may reduce ventilation and concomitant use of sedating medications such as benzodiazepines,gabapentinoids,muscle relaxants and other central nervous system depressants.^[24] Benzodiazepine use with opioids increases the risk of overdose death by four-fold, whereas concomitant use with gabapentintoids such asgabapentin orpregabalin increases the risk of overdose death by nearly two-fold.^[24]

Higher doses of prescription opioids, as well as long-acting formulations, are associated with an increased risk of overdose.^[24] In those on long-term opioid treatment for chronic pain, daily morphine equivalents greater than 200 mg were associated with death from opioid related causes (including overdose) in 3.8% of men and 2.2% of women.^[24] Opioids are the most common cause for serious accidental poisonings of children in the UK.^[25]

Opioids are primarily metabolized in theliver, before being excreted through urine. Opioids are metabolized by phase 1 and/or phase 2metabolism, which can lead to the activation or inhibition of these drugs.^[26][3] Phase 1 metabolism is the CYP pathway which consists of differentcytochrome P450s – a set of enzymes that catalyzehydrolysis,reduction, andoxidation reactions – to create an activemetabolite.^[27] In contrast, Phase 2 metabolism causes the opioids to undergo conjugation, with little to no interaction with the CYP pathway.^[27] The opioids undergo phase 1 and phase 2 metabolism until they arehydrophilic enough to berenally excreted.^[26]

Various factors play a role in how an opioid is metabolized. In phase 1 metabolism, the CYP family has severalpolymorphisms, which can account for the difference intherapeutic responses within each individual.^[28] This diversification leads to opioids being modified at varying rates, which can cause the drug to remain in thebloodstream for either a longer or shorter period.^[28] Therefore, these polymorphisms control opioidtolerance and facilitateoverdose.

Evidence suggests that mental health can be a significant facilitator for opioid use disorder.^[29] Given that opioids are prescribed for pain management, mental health disorders, such asdepression, have been shown to increase use of opioids when treating conditions associated withchronic pain.^[29] Evidence has shown that individuals withmood andanxiety disorders have an increased likelihood of being prescribed opioids and continuing usage for lengthy periods of time, consequently increasing likelihood fordependence.^[30] As such, affected individuals have almost double the risk of using opioids for pain relief in the long-term.^[30] Additionally, mental health challenges associated with trauma, economic depression, social environments conducive to substance use and risk-taking behaviours have been shown to increase opioid misuse.^[31] Furthermore, mental health challenges associated withcardiovascular disease,sleep disorders, andHIV can cause opioid dependence and subsequent overdose.^[32] Notably, cyclic behaviours can be observed between mental illness and opioid use disorder where individuals with mental health diagnoses engage in opioid use which further perpetuates mental health challenges and increased drug usage.^[32]

Opioids bind with neural opioid receptors to provokeanalgesic,sedative, andeuphoric effects.^[16] Opioids function by stimulating specificG-protein coupled receptors distributed throughout the body—including the brain, skin and spinal cord.^[16] Three of the major opioid receptors include mu, kappa, delta, and nociception, each playing a role in eliciting the effects associated with opioids.^[33] An opioid overdose results from over-activation of these receptors, which can cause permanent brain damage from cerebral hypoxia orneurotoxicity.^[34][7]

Mu receptors have ananalgesic effect on the brain, and are found in various parts of the nervous system including thecerebral cortex andthalamus.^[16] They can be found in thenucleus accumbens, the pleasure centre of the brain, as well as theamygdala.^[16]Kappa receptors, in thehypothalamus, produce a similaranalgesic effect. They bind withdynorphins to stimulate anti-reward effects —dysphoria— and other negative effects of withdrawal. Whilemu receptors are the source of addiction,kappa receptors contribute to continued use. They generatedysphoria in response to increasing stress levels viacorticotropin-releasing factor (CRF).^[16] This increases erratic shifts in mood during the withdrawal period and can prompt relapse.^[16]Delta receptors, found in thebasal ganglia of thelimbic system, have been shown to reduceanxiety by binding withenkephalins, although this requires further research.^[16] The most recent addition to these receptors arenociception opioid receptors. Although they have been determined to be receptors to certainligands from opioids, their role is not yet fully understood.^[35]

When opioids are ingested, theligand binds to these constitutively active receptors to reduceneural activity.^[33] This is accomplished by inhibitingadenylyl cyclase andcyclic AMP, which are necessary for communication within thecentral nervous system.^[33] There is research indicating that opioids reduce pain by disruptingion channels andvesicle fusion.^[33]

Prolonged exposure to opioids can cause these receptors to become internalized, leading to increased tolerance and increased opioid use.^[17]

Opioid overdoses can often be prevented.^[36][37] Clear protocols for staff at emergency departments and urgent care centers can reduce opioid prescriptions for individuals presenting in these settings who engage indrug seeking behaviors or who have a history of a substance use disorder.^[38] Drug seeking behaviors include but are not limited to obsessiveness or impatience when it comes to attaining medications, seeking multiple pain adjunct medications, and inconsistent physiological presentation.^[39] Aprescription monitoring program may help determine if an individual is receiving a high doses of opioids or combinations of medications such as benzodiazepines and opioids that put them at high risk.^[40] Limited amount of evidence suggests opioid therapy with extended-release or long-acting formulations may increase the risk of an unintentional overdose compared to shorter-acting agents.^[41] Routinely screening using tools such as theCAGE-AID and the Drug Abuse Screening Test (DAST-10) in adults and theCRAFFT in those aged 14–18 years is recommended.^[36] The revised risk index for overdose or severe opioid induced respiratory depression (RIOSORD) is a validated screening tool that may be used to estimate the risk of overdose in people using opioids, or the rapid opioid dependence screen may be used as a more rapid and succinct method to screen for opioid use disorder.^[24] Other "drug seeking" behaviors and physical indications of drug use should be used as clues to perform formal screenings.^[36]

There are several medication-assisted treatments available for people with opioid use disorder or opioid dependence who are at higher risk for opioid overdose.^[1][42] The selection of treatment depends on various factors, such as a person's preference, accessibility, and history of treatment.^[42] Examples of medication-assisted treatments arebuprenorphine (with or without naloxone),naltrexone, andmethadone.^[43][44] Methadone and buprenorphine are associated with reduced mortality in those with opioid use disorder as well as higher drug treatment program retention, lower illicit drug use, and decreased overdose deaths.^[24] The mortality benefit of long-term naltrexone use in those with opioid use disorder is less well-established.^[24] After a non-fatal opioid overdose, subsequent methadone or buprenorphine initiation and use reduce the risk of overdose death by 59% and 38%, respectively. Initiating buprenorphine in the emergency department is associated with lower mortality and increased adherence to opioid use disorder treatment programs.^[24] Peer support groups have tentative evidence of benefit.^[45] There is also some evidence indicating benefits in community-based overdose education and naloxone distribution programs.^[46] Buprenorphine and methadone can help decrease drug cravings.^[42] Combining pharmacologic treatments with behavioral therapy, such as support or recovery groups, can increase the likelihood of overcoming addiction and reduce the risk of an opioid overdose.

Individuals diagnosed with opioid dependence should be prescribed naloxone to prevent overdose. They should be directed to one of the treatment options available, such as needle exchange programs and treatment centers.^[36][37] A naloxone prescription is also recommended when risk factors for opioid overdose are present, such as a history of overdose, substance use disorder, or higher doses of opioids.^[40] With the CDC recommending naloxone be provided to all people on long term opioids who have risk factors for overdose, including a history of a substance use disorder, daily morphine equivalents greater than 50 mg or concurrent benzodiazepine use.^[24] Briefmotivational interviewing can also be performed and has been shown to improve people's motivation to change their behavior.^[36][47] Despite these opportunities, the dissemination of prevention interventions in the US has been hampered by the lack of coordination and sluggish federal government response.^[37]

Unused or old opioids should not be stored in the home as there is a risk of people using the drugs for non-medical purposes. Among adolescents and young-adults, non-medical use of prescription opioids is associated with a subsequent 13-fold increased risk of heroin use later in life.^[24] Opioids that are no longer being used may be taken to drug take back programs at local pharmacies, healthcare facilities or law enforcement agencies for safe disposal. The United StatesFood and Drug Administration also has a "flush list"; a list of medications that may be safely disposed of by flushing down the toilet.^[48]

In the United States, 49 states and the District of Columbia have expanded naloxone access at a pharmacy level via standing order, protocol order, naloxone-specific collaborative practice agreement, or pharmacist prescriptive authority.^[49]

If someone is suspected to have overdosed on opioids, call for medical attention, administernaloxone, and providebasic life support as soon as possible.^[50]

Naloxone works by temporarily blocking the effects of opioids, including respiratory depression and sedation.^[50][3] Naloxone is safe and side effects are rare, generally limited to allergic reactions.^[51] It should be given if there is any suspicion of an opioid overdose. Naloxone is available to the public in the United States in two routes of administration:intranasal andintramuscular/subcutaneous. Intranasal forms include Narcan, approved in 2015, and Kloxxado, approved in 2021.^[52] Formulations that are injectable into the intramuscular or subcutaneous spaces include Evzio, approved in 2014, and Zimhi, approved in 2021.^[53][54] The doses are approved for both children and adults and may be repeated every 2–3 minutes.^[52][53][54] Synthetic opioids likefentanyl andcarfentanil are much more potent than prescription opioids andheroin.^[55] There is some debate about whether increased doses of naloxone are required to reverse overdose from synthetic opioids; however, this concern has prompted FDA approval of higher dose naloxone formulations such as Kloxxado and Zimhi.^[52][56] The effects of naloxone last for approximately 30-90 minutes, at which point opioids present in the body may begin to take effect again depending on the specific opioids duration of action. Therefore, transport to a hospital is indicated after naloxone administration, and the medication may need to be re-administered.^[24]

The examples and perspective in this sectiondeal primarily with the United States and do not represent aworldwide view of the subject. You mayimprove this section, discuss the issue on thetalk page, or create a new section, as appropriate.(February 2024) (Learn how and when to remove this message)

Opioid overdose should be reversed as soon as possible. To shorten the time between overdose and naloxone administration, multiple programs have been enacted to improve naloxone access for drug users, caregivers, and first responders.^[59] In the US, these efforts include FDA approval of intranasal and injectable naloxone over the counter, professional organizations recommending physicians to co-prescribe naloxone when opioids are used for pain management, free community overdose education and naloxone distribution (OEND) programs, and efforts to train non-medical first responders such as firefighters and police to use naloxone. These actions have reduced opioid-related deaths at the state and national levels and are cost-effective.^[59][60]

In the UK, naloxone is a prescription-only medicine, but drug treatment services can supply it without a prescription. In an emergency, anyone can use it as a life-saving measure.^[61]

In August 2024, a new device was developed by researchers atMIT andBrigham and Women's Hospital that can be implanted under the skin, which rapidly releases naloxone when an overdose is detected.^[62]

Opioid overdose leads to death when people stop breathing.^[63] Bystanders trained in first aid can evaluate people who have overdosed and provide basic life support including rescue breathing viabag valve mask ormouth to mouth. If the person who has overdosed does not have a pulse, rescuers should beginCPR.^[50]

Another medication that can be used to treat opioid overdoses isNalmefene, which is an opioid derivative structurally similar toNaltrexone. It works similarly to Naloxone but has a longer half-life.^[64] It is approved for intravenous, intramuscular, and subcutaneous administration by prescription only, unlike the over the counter formulations of naloxone.^[65]

The examples and perspective in this articlemay not represent aworldwide view of the subject. You mayimprove this article, discuss the issue on thetalk page, orcreate a new article, as appropriate.(October 2018) (Learn how and when to remove this message)

In 2016, the World Health Organization estimated that 34 million people used opioids and 19 million used opiates.^[1] Of these, about 27 million people had opioid dependence, with the majority—but a decreasing number—using illicit heroin.^[1] In 2015, 118,000 people died from opioid use disorders, causing almost one-third of all drug-related deaths.^[1]

Of the 70,200overdose deaths in the US in 2017, opioids were involved in 47,600, with three male deaths for each female death.^[2] This is an increase from 2016 where over 64,000 died from drug overdose, and opioids were involved in over 42,000.^[67] In 2017, the five states with the highest rates of death due to drug overdose wereWest Virginia (57.8 per 100,000),Ohio (46.3 per 100,000),Pennsylvania (44.3 per 100,000),Kentucky (37.2 per 100,000), andNew Hampshire (37.0 per 100,000).^[68]

Concerning the 2017 data in the charts below, deaths from the various drugs add up to more than 70,200 because multiple substances are involved in many of the deaths.^[2] According to theNational Safety Council, the lifetime odds of dying from an overdose in the United States is 1 in 96.^[69]

In 2023, the most opioid overdose deaths were amongWhites (47,754), followed byBlacks (16,481),Latinos (11,310),Native Americans (1,170), andAsians (695).^[70]

• Charts of deaths involving specific opioids and classes of opioids
• 
  US yearly deaths from all opioid drugs. Included in this number are opioid analgesics, along withheroin and illicitsynthetic opioids.^[2]
• 
  US yearly deaths involving othersynthetic opioids, predominatelyFentanyl.^[2]
• 
  US yearly deaths involving prescription opioids.Non-methadone synthetics is a category dominated by illegally acquiredfentanyl, and has been excluded.^[2]
• 
  US yearly overdose deaths involving heroin.^[2]

TheSubstance Abuse and Mental Health Services Administration hosts an annual health observance known as National Prevention Week. Every third week of May, they encourage communities across the country to unite to share stories about positive mental and behavioral health and the importance of implementing prevention methods.^[72] They also sponsor Recovery Month every September. Recovery Month aims to raise awareness about mental and substance use disorders and to honor individuals who recover, promoting the positive message that prevention works and that treatment is effective.^[73]

International Overdose Awareness Day is on 31 August to remember those who have died from an overdose, to decrease the stigma of drug-related deaths, and to promote the prevention of overdose.^[74]

• Harm reduction
• List of deaths from drug overdose and intoxication
• Responsible drug use

• WHO fact sheet on opioid overdose
• Community management of opioid overdose(PDF). World Health Organization. 2014.ISBN 978-92-4-154881-6. Archived fromthe original(PDF) on 1 September 2022.

• Poisoning by drugs, medicaments and biological substances
• Drug overdose
• Opioids
• Medical emergencies
• Causes of death

• All articles with unsourced statements
• Articles with unsourced statements from April 2024
• CS1 errors: generic name
• CS1 maint: numeric names: authors list
• Articles with short description
• Short description is different from Wikidata
• Articles needing cleanup from July 2025
• All pages needing cleanup
• Articles containing how-to sections
• Use dmy dates from September 2025
• Articles with limited geographic scope from February 2024
• United States-centric
• Articles with limited geographic scope from October 2018
• Wikipedia medicine articles ready to translate