Opioid intoxication
Intoxication - opioids; Opioid abuse - intoxication; Opioid use - intoxicationOpioid-based medicines include morphine, oxycodone, and synthetic (man-made) opioid narcotics, such as fentanyl. They are often prescribed to treat pain after an injury, surgery, or a dental procedure. Sometimes, they are used to treat severe cough or diarrhea. The illegal drug heroin is also an opioid. When abused, opioids cause a person to feel relaxed and intensely happy (euphoria). In short, the medicines are used to get high.
Opioid intoxication is a condition in which you're not only high from using the medicine, but you may also have body-wide symptoms that can make you ill or impaired.
-
Causes
Opioid intoxication may occur when a health care provider prescribes an opioid, but:
- The dose is too high for the person.
- The provider doesn't know the person is already taking another opioid at home.
- The provider prescribes a sleep medicine (sedative) in addition to the opioid.
- The provider doesn't know that another provider already prescribed an opioid or sedative.
- The person has a health problem, such as a liver or kidney problem, that may easily result in intoxication.
In people who use opioids to get high, intoxication may be caused by:
- Using too much of the medicine
- Using an opioid with certain other medicines, such as sleep medicine or alcohol
- Taking the opioid in ways not normally used, such as smoked or inhaled through the nose (snorted)
-
Symptoms
Symptoms depend on how much of the medicine is taken.
Symptoms of opioid intoxication can include:
- Altered mental status, such as confusion, delirium, or decreased awareness or responsiveness
- Breathing problems (breathing may slow and eventually stop)
- Extreme sleepiness or loss of alertness
- Nausea and vomiting
- Small pupils
-
Exams and Tests
Tests that are ordered depend on the provider's concern for additional medical problems. Tests may include:
- Blood tests
- CT scan of the brain, if the person is having seizures or might have a head injury
- Electrocardiogram (ECG) to measure electrical activity in the heart
- Chest x-ray to check for pneumonia
- Toxicology (poison) screening
-
Treatment
The provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated as appropriate. The person may receive:
- Breathing support, including oxygen, or a tube that goes through the mouth into the lungs and attachment to a breathing machine (ventilator)
- Intravenous fluids (fluids given through a vein)
- Medicine called naloxone (Evzio, Narcan) to block the effect of the opioid on the central nervous system
- Other medicines as needed
Since the effect of the naloxone is often short, your health care team may monitor you for 4 to 6 hours in the emergency department. People with moderate to severe intoxication will often be admitted to the hospital for 24 to 48 hours.
A mental health evaluation is needed if the person is suicidal.
-
Outlook (Prognosis)
Many factors determine the short- and long-term outcome after opioid intoxication. Some of these are:
- The degree of poisoning, for example, if the person stopped breathing, and for how long
- How often the medicines are used
- Effect of impurities mixed in with illegal substances
- Injuries that occur as a result of the medicine use
- Underlying medical conditions
-
Possible Complications
Health problems that may occur include any of the following:
- Permanent lung damage
- Seizures, tremors
- Reduced ability to think clearly
- Unsteadiness and difficulty walking
- Infections or even permanent damage of the organs as a result of injection use of the drug
References
Aronson JK. Opioid receptor agonists. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:348-380.
Brust JCM. Effects of drug abuse on the nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 87.
National Institute on Drug Abuse website. Opioids. nida.nih.gov/research-topics/opioids. Updated November 2024. Accessed July 11, 2025.
National Institute on Drug Abuse website. Heroin research report: what are the medical complications of chronic heroin use? nida.nih.gov/publications/research-reports/heroin/what-are-medical-complications-chronic-heroin-use. Updated July 2011. Accessed April 16, 2025.
Nikolaides JK, Thompson TM. Opioids. In: Walls RM, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 151.




