Orange stars

Opioid Use Disorder

Full Review: Jun 2026 ByMashal Khan, MD, NewYork-Presbyterian Hospital | Evguenia Makovkina, MD, New York-Presbyterian Hospital-Weill Cornell
Last updated: Jun 2026
v835643
VIEW PROFESSIONAL VERSION

Opioids, a class of drugs derived from the opium poppy (including synthetic variations), are powerful pain relievers that have a high potential for misuse.

  • Opioids are used to relieve pain, but they also cause euphoria (an exaggerated sense of well-being) and, with prolonged use, dependence and addiction.

  • Taking too much of an opioid can be fatal because opioids can slow breathing to a complete stop.

  • There are laboratory tests (typically urine is tested) that can be done to check for the presence of opioids.

  • Treatment strategies include detoxification (stopping the drug), substitution (substituting another drug and gradually reducing its dose), and maintenance (substituting another drug that is taken indefinitely).

  • Ongoing counseling and psychosocial support are essential in all treatment strategies.

"Opioid" is the term used to refer to a number of substances derived from the opium poppy (mainly from its unripe seed pods) and those that are man-made and mimic the effects of the natural product. Opioids come in natural, synthetic,and semisynthetic variations (see table ).

Opioids have a legitimate medical use as powerful pain relievers. They include codeine (a natural opioid that has a low potential for dependence), oxycodone (a semisynthetic opioid that is used alone and in various combinations, such as oxycodone plus acetaminophen), morphine, pentazocine, and hydromorphone. Chronic severe pain can be treated with methadone (a fully synthetic opioid taken by mouth) and fentanyl (a semisynthetic opioid absorbed through a skin patch). Heroin is a potent, semisynthetic opioid that is illegal in the United States, but it is used in very limited treatment applications in other countries.

Table
Table

Use and misuse of opioids in their illicit and prescribed forms is relatively common worldwide, because these drugs are widely available and cause an exaggerated sense of well-being. According to 2024 data gathered in the United States, nearly 8 million people age 12 and older used or misused opioids overall. Over 90% of them misused prescription opioids, 3% misused both prescription opioids and heroin, and 4% illicitly used heroin alone.

People can become dependent on any opioid. (See also Drug Use and Misuse.)

Serious dependence and addiction rarely occur when people use opioids to treat a brief episode of severe pain (for example, from a burn or broken bone). Although many people who use opioids to relieve pain for more than several days feel some mild symptoms of opioid withdrawal when they stop, people who take opioids for a long time to treat chronic pain are at increased risk of developing opioid use disorder.

Tolerance to opioids can develop after a few days of continued opioid use. That is, people need more and more of a drug to feel the effects originally produced by a smaller amount. People may become more tolerant to some effects than to others. Although people with a substance use disorder often have tolerance to a drug, having tolerance by itself does not mean that a person has a substance use disorder; however, tolerance can promote physical dependence on the opioid.

Opioid use disorder (sometimes abbreviated OUD) is the term for a diagnosable illness in which people continue to use opioids despite the desire to stop using and despite negative health, social, or job-related consequences. They experience craving for opioids, spend excessive time seeking them out, and require increasing amounts of opioid to have the desired effect (due to tolerance). Additionally, people with opioid use disorder can experience withdrawal symptoms when they stop using opioids. The term opioid use disorder is more precise than "addiction" and carries less stigma.

Did You Know...

  • The language surrounding substance use disorders has changed to lessen the stigma associated with these disorders and, therefore, make it more likely that a person will seek treatment. The word "abuse" has been replaced by "use" when discussing illicit drugs and "misuse" when discussing the improper use of prescription medications.

Symptoms and Signs of Opioid Toxicity and Withdrawal

Opioids cause immediate and sometimes long-term symptoms.

Immediate effects

Opioids dull pain and are strong sedating drugs. Opioids may also cause euphoria.

Other, less desirable effects include

  • Constipation

  • Nausea and vomiting

  • Facial flushing

  • Itching

  • Confusion (especially in older adults)

The products that result from the breakdown (metabolism) of the opioid meperidine can cause seizures.

When taken with certain other drugs, some opioids can cause a serious disorder called serotonin syndrome. This syndrome is characterized by confusion, tremors, involuntary muscle spasms or twitching, agitation, excessive sweating, and a high body temperature.

A rare condition called spongiform leukoencephalopathy has been reported in heroin users who inhale the drug. Symptoms vary and may include motor restlessness, apathy, impaired coordination (ataxia), or paralysis. The symptoms may resolve, or they can progress to problems with the autonomic nervous system and death.

Overdose

Taking too much of an opioid at once (overdose) is life threatening because it causes breathing to become dangerously slow and shallow. Blood pressure, heart rate, and body temperature may decrease, and pupils constrict (becoming like pinpoints). Eventually, people become unconscious or die, usually because breathing stops. Combining opioids with alcohol or other sedatives is even more lethal.

In the United States in 2022 and 2023, about 80,000 people died each year from an opioid overdose. Between 2023 and 2024, the overall drug overdose death rate fell 26% Many of those deaths involved opioids.

Long-term effects

Opioids themselves do not cause many long-term complications other than dependence. Some people have minor side effects such as chronic constipation, excessive sweating, sleepiness, or decreased libido. However, many serious complications can result from sharing needles with another person and from unknowingly injecting other substances with the opioid.

Withdrawal symptoms

Opioid withdrawal is uncomfortable but rarely life threatening. Symptoms can appear as early as 4 hours after opioid use stops and generally peak within 48 to 72 hours. They usually subside after about a week, although the time frame can vary considerably depending on which opioid is used.

Each opioid is eliminated from the body at a different rate, which alters how quickly withdrawal progresses and stops. Withdrawal symptoms are worse in people who have used large doses for a long time:

  • At first, people feel anxious and crave the drug.

  • Breathing becomes rapid, usually accompanied by yawning, perspiration, watery eyes, a runny nose, dilated pupils, and stomach cramps.

  • Later, people may become hyperactive and agitated and have a heightened sense of alertness.

  • Heart rate and blood pressure increase.

Other withdrawal symptoms include

  • Gooseflesh

  • Tremors

  • Muscle twitching

  • Fever and chills

  • Aching muscles

  • Loss of appetite

  • Nausea and vomiting

  • Diarrhea

Opioid use during pregnancy is especially serious because heroin and methadone easily cross the placenta and affect the fetus (see How Medications Cross the Placenta). Because babies born to people who use opioids have been exposed to the drugs while in the womb, they may quickly develop withdrawal symptoms, including

  • Tremors

  • High-pitched crying

  • Jitters

  • Seizures

  • Rapid breathing

Opioid withdrawal symptoms in newborn babies are called neonatal abstinence syndrome"

If mothers take opioids immediately before labor and delivery, the baby’s breathing may be weak. (See also Opioids During Pregnancy.)

Did You Know...

  • Taking opioids for a brief time to relieve the pain of an immediate injury, if supervised by a doctor, rarely leads to addiction. The risk of addiction is higher, however, in people who currently have or previously had a substance use disorder.

  • Taking opioids during pregnancy can cause addiction in the fetus and withdrawal symptoms in the newborn.

Diagnosis of Opioid Toxicity or Withdrawal

  • A doctor's evaluation

  • Sometimes urine tests

  • Sometimes an approved withdrawal scale

Lab Test

Acute opioid intoxication is usually apparent based on what people or their friends tell the doctor and on results of the physical examination. If it is not clear why a person is acting abnormally, doctors may do tests to exclude other possible causes of symptoms, such as a low blood sugar level or a head injury. Doctors can also do urine tests to check for the drug or assess the person using an approved assessment tool call a withdrawal scale to determine how serious the opioid addiction is. Other tests may be done to check for complications.

Treatment of Opioid Toxicity or Withdrawal

An opioid overdose requires emergency treatment, but the ultimate and difficult goal of treatment is to help people control their use of opioids. Treatment can include

  • Emergency treatment

  • Detoxification

  • Possible maintenance treatment (for people who are unable to quit)

  • Rehabilitation

Emergency treatment

An opioid overdose is a medical emergency that must be treated quickly to prevent death. Breathing may require support, sometimes with a ventilator, if the overdose has suppressed breathing.

A medication called naloxone is given as an antidote to the opioid, rapidly reversing all side effects. It is given by injection or by nasal spray. Because some people briefly become agitated and delirious before they become fully conscious, physical restraints may be applied for a short time. Because naloxone causes withdrawal symptoms in people who are dependent on opioids, it is used only when necessary (as when breathing is weak).

People recovering from an overdose should be observed for several hours until the effects of naloxone have worn off to be sure that no side effects of the opioid remain. If people took an opioid with long-lasting effects (such as methadone or slow-release forms of other opioids), they are usually observed for a longer time.

If symptoms redevelop, people may be given another dose of naloxone, be admitted to the hospital, or both.

Detoxification

There are several approaches to detoxification:

  • Substituting a similar but less potent drug, then gradually decreasing the dose and stopping the drug

  • Providing psychosocial and psychotherapeutic support

During detoxification, treatment is usually needed to lessen the symptoms of withdrawal. The medication clonidine usually provides some relief. However, clonidine may cause side effects, such as low blood pressure and drowsiness. Stopping clonidine may itself cause withdrawal symptoms, such as restlessness, insomnia, irritability, a fast heartbeat, and headaches.

Substitution typically involves giving drugs such as buprenorphine and methadone, which are then slowly decreased and eventually stopped completely.

  • Buprenorphine is a mixed opioid agonist and antagonist. That means it has some of the effects of opioids (agonist) but also blocks some of the effects of opioids (antagonist). It can be given orally (usually under the tongue) or injected if withdrawal symptoms are severe. When used orally, it does not require supervision in a special program, and thus doctors who are trained in its use can prescribe it in their office. In many countries, buprenorphine has replaced methadone as the medication of choice in detoxification programs.

    Naloxone is sometimes added to buprenorphine, but this combination must be administered very carefully because it produces different effects depending on whether it is given by mouth or injected.

  • Methadone is an opioid that is taken by mouth. It blocks withdrawal symptoms and the craving for other opioids, especially heroin. Because methadone’s effects last much longer than those of other opioids, it can be taken less frequently, usually once a day. The dose can then be decreased slowly. The use of methadone must be supervised in a licensed methadone treatment program. Large doses of methadone sometimes cause abnormal heart rhythms. Therefore, people on this drug are monitored closely when it is started or if the dose is changed.

Detoxification must be followed by rehabilitation to prevent a return to opioid use. Ongoing treatment may include long-term counseling and support and medications such as naltrexone, a long-acting opioid antagonist that reduces cravings and help prevent relapse.

Maintenance treatment

For people who continually return to using opioids (called opioid use disorder), another approach—called maintenance—is often preferred. It involves substituting a prescribed medication at a regular dose that the user takes for a long time (months or years) rather than decreasing the dose and eventually stopping the medication. Methadone, buprenorphine, or naltrexone may be used as substitutes for opioids.

Maintaining opioid users with regular doses of 1 of these medications enables them to be socially productive because they do not have to spend time seeking the illicit opioid and because the medications used do not interfere with functioning the way that illicit drug use does. For some opioid users, the treatment works. For many, lifelong maintenance is necessary.

Buprenorphine has become more widely used as maintenance treatment in the past decade because it can be prescribed by doctors in their office. Thus, opioid users do not have to go to a federally regulated clinic.

Methadone suppresses withdrawal symptoms and the craving for the opioid without making opioid users overly drowsy or euphoric. However, due to federal laws around methadone dispensing for opioid use disorder, people who are treated with methadone must appear at a clinic where methadone is dispensed in the amount that prevents severe withdrawal symptoms, minimizes craving, and supports daily functioning. The requirement of in-person attendance can pose a barrier to accessing treatment in a methadone program for some patients.

Naltrexone is a medication that blocks the effects of opioids (opioid antagonist). Before starting naltrexone, people must be fully detoxified from opioids, or else a severe withdrawal reaction can occur. Depending on the dose, naltrexone’s effects last from 24 to 72 hours. Thus, the medication can be taken once a day or as few as 3 times a week. Because this medication has no opioid effects, naltrexone is most useful for opioid users who are strongly motivated to remain free of opioids and who are not severely dependent on opioids.

Clonidine is another medication that can suppress symptoms of withdrawal. A variety of other drugs can relieve the symptoms associated with withdrawal, including acetaminophen and ibuprofen for pain, loperamide for diarrhea, ondansetron to prevent nausea and vomiting, and benzodiazepines for anxiety and agitation.

Rehabilitation

Regardless of which approach is used, ongoing counseling and support is essential. Support may include specially trained doctors, nurses, counselors, opioid maintenance programs, family members, friends, and other people with the same substance use disorder (support groups).

The therapeutic community concept emerged nearly 25 years ago in response to the problems of heroin use. Samaritan Daytop Village and Phoenix House pioneered this nondrug approach. Opioid users live in a communal, residential center for an extended period of time. These programs help people build new lives through training, education, and redirection. The programs have helped many people, but initial dropout rates are high.

Questions about precisely how well these programs have worked and how widely they should be applied remain unanswered. Because these programs require a lot of resources to run, many people may be unable to afford them.

More Information

The following English-language resources may be useful. Please note that The Manual is not responsible for the content of these resources.

  1. National Institute on Drug Abuse (NIDA)

  2. Substance Abuse and Mental Health Services Administration (SAMHSA)

Drug Information for the Topic

quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
iOS ANDROID
iOS ANDROID
iOS ANDROID