Narcan is one brand of naloxone, a medicine used along with emergency medical treatment to reverse the life-threatening effects of a known or suspected opioid overdose in adults and children [1]. The Food and Drug Administration calls it a lifesaving emergency treatment that reverses opioid overdose, a medicine with no abuse potential, and not a controlled substance [2].
It is not a treatment for opioid addiction. The FDA has approved three medications for opioid use disorder, and naloxone is not among them: buprenorphine, methadone and naltrexone [3]. Keeping those two ideas apart is the single most useful thing this page can do, because one of them is for the worst ten minutes of someone’s life and the other is for the years after.
This page covers what naloxone does, how an overdose is recognized, why it is not the same as naltrexone, who the FDA says should carry it, what the side effects are, and what has to happen next. Our explainer on medication-assisted treatment covers the medications that do treat opioid use disorder.
If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
What naloxone is and what it does during an overdose
Naloxone belongs to a class of medications called opiate antagonists, and it works by blocking the effects of opiates to relieve dangerous symptoms caused by high levels of opiates in the blood [1].
In plain terms, opioids slow breathing down until it stops. Naloxone pushes them off the receptors they are sitting on, and breathing restarts. It is sold as a nasal spray and as an injection [4], under brand names including Kloxxado, Narcan and Rezenopy [1].
It works quickly. The FDA says that when naloxone is given soon after someone starts experiencing an overdose, the person will usually wake up within one to three minutes, and that repeat administration may be necessary [4].
The part people miss is how briefly it lasts. Naloxone is a temporary treatment, and its effects do not last long, which is why the FDA says it is extremely important to still call 911 [4]. The opioid is still in the body. The rescue medicine wears off first.
Two other facts are worth holding on to. Naloxone is not addictive [4], and it has no abuse potential and is not a controlled substance [2]. Nothing about carrying it creates a new risk.
If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
How to recognize an opioid overdose
The FDA lists the signs of an opioid overdose as unconsciousness or unresponsiveness, meaning the person does not wake up when shaken or called; shallow breathing; limpness; blue lips, gums or fingertips; and a slow or irregular heartbeat or pulse [4].
Federal drug information adds two more that are easier to check in a dim room: the person does not wake when spoken to in a loud voice or when the middle of the chest is rubbed firmly, and the pupils are small [1].
People hesitate because they are not certain. The FDA’s answer to that is direct. If someone is having a medical emergency other than an opioid overdose, such as a diabetic coma or cardiac arrest, giving them naloxone will generally not have any effect or cause them additional harm [4]. It can be given to people of all ages, including infants, children and the elderly [4].
Every naloxone product comes with the manufacturer’s instructions, and a pharmacist will walk through them [1]. This page does not reproduce them, because the leaflet in the box is written for the device in your hand and this page is not.
If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
Naloxone is not a treatment for opioid use disorder
This is where the confusion does real damage, and it starts with two names that are one letter apart.
Naloxone reverses an overdose that is happening now. Naltrexone is one of the three medications the FDA has approved to treat opioid use disorder, alongside buprenorphine and methadone [3]. The FDA estimates that over 6.1 million people aged 12 or older have an opioid use disorder [3].
Naltrexone can help prevent a return to use, and it comes as a pill or an injection [5]. It is not interchangeable with rescue naloxone, and it carries a risk in the other direction: naltrexone can bring about a sudden and severe withdrawal if it is taken while opioids are still in someone’s system [5].
Naloxone does appear inside a treatment medication, which adds to the muddle. Buprenorphine is often combined with naloxone in products such as Suboxone and Zubsolv, where it helps prevent dependence and misuse [5]. That is a different job from the one a rescue spray does. Our pages on buprenorphine and methadone explain how those medications are used.
So a household can need both things at once: a rescue medicine in a drawer, and a treatment plan that is nothing to do with it.
Who the FDA says should have it, and how people get it
Naloxone used to sit behind a prescription counter, and much of it no longer does. The FDA approved the first over-the-counter naloxone nasal spray in March 2023 [2], and has since approved further nonprescription products [4]. Both prescription and nonprescription naloxone nasal sprays are now on the market [1].
The FDA names four groups it recommends carry naloxone [4]:
- people who are prescribed opioid pain relievers
- people who are prescribed medicines to treat opioid use disorder
- people at increased risk of opioid overdose, including those who also use alcohol or other drugs such as benzodiazepines
- caregivers of people at risk of an opioid overdose
Notice that the second group is people already in treatment [4]. Our page on opioid replacement therapy covers what that treatment involves and why it is a separate question from carrying a rescue medicine.
Many states also allow standing orders, which means a person can get naloxone directly from a pharmacist without a prescription, for themselves or for someone else who might be at risk [4].
One piece of upkeep matters. Naloxone devices carry an expiration date, and the advice is to be aware of it and replace the spray once that date passes [1]. A device that has been in a glovebox for four years is not a plan.
Where treatment for opioid use can start in Washington
The Recovery Village Ridgefield is our campus in Ridgefield, Washington. Its own Levels of Care list publishes medical detox, inpatient treatment, a partial hospitalization program, intensive outpatient programming, dual diagnosis treatment and medication-assisted treatment.
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The Recovery Village Ridgefield is part of our family of treatment centers. See the Recovery Village Ridgefield campus.
Side effects, precipitated withdrawal and the limits of one device
Most of the side effects are minor. Federal drug information lists headache, nasal dryness, nasal swelling or congestion, muscle pain, a change in the sense of taste and stomach pain [1].
The serious ones need emergency medical treatment, and one of them is the reason this medicine is sometimes described as unpleasant to receive. Naloxone can produce signs of opiate withdrawal: body aches, diarrhea, a fast, pounding or irregular heartbeat, fever, runny nose, sneezing, sweating, yawning, nausea, vomiting, nervousness, restlessness, irritability, shivering, trembling, stomach cramps, weakness and gooseflesh [1]. Seizures and loss of consciousness are also listed as serious side effects [1]. Our page on opioid withdrawal symptoms describes what that feels like from the inside.
If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
That withdrawal reaction is worth naming honestly, because it explains a reaction families find frightening or hurtful. Someone who wakes up in abrupt withdrawal can be confused, sick and angry. It is a pharmacological event, not an opinion about the person who called for help.
There are also limits on what naloxone reaches. It may not reverse the effects of certain opiates, such as buprenorphine and pentazocine, and those situations may require additional naloxone with a new device each time [1]. The FDA’s own guidance says repeat administration may be necessary [4]. That is another argument for making the 911 call first rather than last.
If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
What has to happen after naloxone works
The minutes after a reversal are not the end of the emergency.
The FDA’s instruction is to call 911, then stay with the person even if they are conscious, until emergency medical help arrives, because they could lapse back into unconsciousness and might need another dose of naloxone [4]. Keep trying to wake them and keep them breathing, and lay an unconscious person on their side so that they do not choke [4].
If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
Then comes the risk almost nobody expects, and it belongs on this page because a reversal is often the moment a period of not using begins. Most opioid overdose deaths occur in people who have just detoxed, because withdrawal reduces a person’s tolerance to the medicine, so those who have just gone through withdrawal can overdose on a much smaller amount than they used to take [5]. The amount that was survivable last month may not be survivable next week.
That is also why the federal guidance does not stop at detox. Most people need long-term treatment after detox, which can include self-help groups, outpatient counseling, intensive outpatient treatment and inpatient treatment [5]. Our pages on medical detox and how admission works set out what each of those steps involves.
Where overdose reversal sits alongside detox and ongoing treatment
Naloxone sits at one end of a line, and the rest of the line is where the work happens.
At the emergency end is a reversal and an ambulance. Next is withdrawal management with medical staff watching, which is what residential and inpatient care is built around when someone needs a bed and daily review. Below that sit step-down levels, including outpatient programs that let someone keep working while the clinical hours continue. Our explainer on levels of care sets out how those tiers differ.
Medication runs through all of it rather than sitting in one tier. Buprenorphine, methadone and naltrexone are all approved treatments for opioid use disorder [3], and our overview of opioid addiction treatment explains how a program combines them with counseling.
Cost is usually the next question, and it is answered per plan rather than in general. Our pages on insurance coverage for rehab and what treatment costs explain the terms before a benefits call, and our treatment centers lists the campuses we run.
Frequently Asked Questions
What is Narcan used for? Narcan is a brand of naloxone, used along with emergency medical treatment to reverse the life-threatening effects of a known or suspected opioid overdose in adults and children. It blocks the effects of opiates to relieve the dangerous symptoms caused by high levels of opiates in the blood. If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
Is Narcan the same thing as naltrexone? No. Naloxone reverses an overdose that is happening now. Naltrexone is one of three medications the FDA has approved to treat opioid use disorder, with buprenorphine and methadone. Naltrexone comes as a pill or an injection and can help prevent a return to use, but it can bring about a sudden and severe withdrawal if it is taken while opioids are still in someone’s system.
Do you still need to call 911 after giving someone naloxone? Yes. Naloxone is a temporary treatment and its effects do not last long, so the FDA says it is extremely important to still call 911. After calling, stay with the person even if they are conscious, because they could lapse back into unconsciousness and might need another dose. If someone is having a seizure, is unresponsive or has trouble breathing, call 911. For a mental-health crisis call or text 988.
What are the side effects of naloxone? Federal drug information lists headache, nasal dryness, swelling or congestion, muscle pain, a change in the sense of taste and stomach pain. Serious side effects that need emergency treatment include signs of opiate withdrawal such as body aches, diarrhea, fever, sweating, nausea and trembling, along with seizures and loss of consciousness. If someone is having a seizure, is unresponsive or has trouble breathing, call 911.
Can you buy naloxone without a prescription? Often, yes. The FDA approved the first over-the-counter naloxone nasal spray in March 2023 and has since approved further nonprescription products. Both prescription and nonprescription nasal sprays are on the market. Many states also allow standing orders, which let a person get naloxone directly from a pharmacist without a prescription, for themselves or for someone else at risk.
Sources
- MedlinePlus. (2024). Naloxone Nasal Spray. U.S. National Library of Medicine, National Institutes of Health. https://medlineplus.gov/druginfo/meds/a616003.html
- U.S. Food and Drug Administration. (2024). Information about Naloxone and Nalmefene. FDA. https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/information-about-naloxone
- U.S. Food and Drug Administration. (2024). Information about Medications for Opioid Use Disorder (MOUD). FDA. https://www.fda.gov/drugs/information-drug-class/information-about-medications-opioid-use-disorder-moud
- U.S. Food and Drug Administration. (2026). Access to Naloxone Can Save a Life During an Opioid Overdose. FDA Consumer Updates. https://www.fda.gov/consumers/consumer-updates/having-naloxone-hand-can-save-life-during-opioid-overdose
- MedlinePlus. Opiate and opioid withdrawal. Medical Encyclopedia, U.S. National Library of Medicine, National Institutes of Health. https://medlineplus.gov/ency/article/000949.htm
This page is for general information and is not medical advice. Only a licensed clinician who knows your history can tell you what is right for you. If you or someone you know is in immediate danger, call 911. For free, confidential support 24/7, call or text 988.
Author
Chief Medical Officer,
The Recovery Village
