Treating Opioid Overdose With Narcan (Naloxone)

Last Updated: November 3, 2023

Editorial Policy | Research Policy

Learn how to use Narcan (naloxone) to prevent opioid overdoses and what could happen if you use it on someone who is not overdosing.

Narcan (naloxone) is a game-changing medicine that has saved the lives of countless people who have overdosed on opioids. Narcan temporarily reverses the effects of opioids, keeping people who have overdosed on opioids alive long enough to get necessary medical care.

What Is Narcan?

Narcan is a brand name for the medicine naloxone given to people who have used too high a dose of opioids. Opioids can cause severe medical problems in high amounts, such as stopping breathing. Narcan reverses opioid effects almost immediately, making it possible to temporarily stop opioid overdose symptoms quickly and effectively.

Narcan Uses

Narcan has only one primary use: to reverse the effects of opioids. Reversing opioids is usually only necessary when someone overdoses.

While the brand name product Narcan is mainly used to treat opioid overdoses, the generic substance naloxone can have other uses. Naloxone can be mixed with some oral opioid medications because it doesn’t have much effect when taken by mouth. If a person takes these opioid medicines by mouth, they will work normally; however, if the oral medicine is crushed and snorted or injected, the naloxone will stop a high from happening. This helps avoid abuse of these medicines.

Naloxone is also used during rapid opiate detox. During this type of detox, a person addicted to opioids is put under anesthesia and given Narcan to cause them to detox artificially fast. Under anesthesia, Narcan could help someone quickly detox more comfortably than using a natural detox method. However, most experts do not recommend rapid detox due to its added risks, high cost and limited effectiveness.

What Does Narcan Do?

Narcan is a medicine known as an opioid antagonist. It connects with the same receptors in the brain that opioids do and keeps opioids from attaching to these receptors. Unlike opioids, however, Narcan does not activate the receptors. Since the opioids are unable to reach or activate these receptors, an opioid overdose can’t continue harming the person while Narcan is active.

Because Narcan almost instantly blocks opioids from working, it will completely reverse all the symptoms caused by opioids. This will eliminate any respiratory suppression so that the person can breathe, but it will also remove any pain relief or sedation the opioids provided.

Narcan Forms

Narcan comes in different forms allowing it to be administered quickly to rapidly reverse the effects of opioids. Narcan will usually be injected or used nasally.

Injectable Narcan

Injectable Narcan is typically only used by healthcare professionals and given through an IV site. Injectable Narcan can be delivered in individual doses or slowly as an IV drip to help maintain treatment of opioid overdose symptoms over a prolonged time.

Auto-Injectable Narcan

Auto-injectable Narcan is designed to be given by anyone in an emergency. It does not go into a vein but into a muscle or fat tissue. Auto-injectable Narcan comes in a special dispensing device that automatically injects Narcan when the end of the device is pressed firmly against the body.

Nasal Spray

Narcan is often provided as a nasal spray to make using it easier. The person helping with nasal Narcan can simply spray a dose into a nostril, avoiding the potential complications of injection while quickly and effectively providing Narcan during an emergency.

Narcan Dosage

The dose of Narcan used depends on its form. Auto-injectable Narcan and nasal Narcan are available in a single dose, making it unnecessary to worry about the amount you are giving. Auto-injectable Narcan comes in a single dose of 2 mg, while nasal Narcan typically comes in a single dose of 4 mg.

The dose of injectable Narcan used by healthcare professionals varies by situation. Because injectable Narcan goes directly into veins, the amount is often smaller than other forms of Narcan, typically starting at doses as low as 0.4 mg.

How To Administer Narcan

When administering Narcan, there are three essential steps. These include:

  1. Recognize that someone potentially needs Narcan. If someone is unresponsive or having problems breathing, and it might be related to an opioid overdose, they should receive Narcan.
  2. Administer the Narcan. Nasal Narcan and auto-injectable Narcan will typically be the forms of Narcan that you have available. These forms of Narcan are designed for emergency use and have clear, obvious instructions. Follow these instructions, either spraying a dose of Narcan into the nostril or using the auto-injector to inject Narcan into the thigh.
  3. Follow up. Narcan only has a temporary effect. You should also call 911 and seek immediate medical care for the person who may be overdosing. If the Narcan does not work or only works slowly, you may need to provide CPR while waiting for emergency services.

How Do You Know When To Give Narcan?

Narcan only works for people specifically using opioids but has almost no risk if given to someone who isn’t using opioids. If someone has symptoms of neurological suppression, such as decreased responsiveness or slow breathing, and they may have overdosed on opioids, you should always give Narcan, even if you are uncertain.

Giving Narcan when someone doesn’t actually need it is very unlikely to be harmful, while not giving Narcan to someone who does need it can result in death. For this reason, anyone suspected of overdosing on opioids should be given Narcan. Healthcare professionals will often give Narcan to unresponsive people who come into an ER to figure out if opioids are causing their symptoms.

What Happens If You Give Narcan To Someone Who Doesn’t Need It?

Narcan is generally considered a safe drug, only very rarely causing any type of side effects, such as an allergic reaction. If someone not using opioids gets Narcan, they will not experience any significant changes, and the drug will have no effect; this is why healthcare experts always recommend giving Narcan if you are unsure whether someone may need it or not.

Narcan Side Effects

Narcan itself does not create any meaningful side effects. When someone is using opioids, however, Narcan has a very noticeable effect. Narcan completely blocks all opioids in the body, leading to withdrawal in a few seconds. This suddenly creates all the symptoms of opioid withdrawal at once. If part of the reason for opioid use is to control pain, the pain will abruptly return at its full intensity.

Effects of Narcan on someone who is using opioids can include:

  • Pain and generalized body aches
  • Agitation
  • Restlessness and irritability
  • Dizziness
  • Nausea and vomiting
  • Diarrhea
  • Fever and chills
  • Sneezing
  • Runny nose

These effects will often begin suddenly and simultaneously within seconds of giving Narcan. Narcan often results in someone going from very unresponsive to highly agitated within one to two minutes.

Where To Buy Narcan

Laws about where Narcan can be purchased vary by state; however, in most states, Narcan can only be bought from a pharmacy with a doctor’s prescription. Doctors may prescribe Narcan to anyone receiving opioids, or may only prescribe it to those that they believe are at risk for potentially overdosing on opioids.

You should speak with your doctor about the laws and regulations in your state to learn where you can get Narcan. Many doctors willingly prescribe Narcan when there is a good reason to.

Narcan Price

Like most drugs, Narcan’s cost varies based on where it is sold, the insurance used, and its form. The price of Narcan can range from less than $30 to over $4,000, depending on these factors. It is good to speak with a pharmacist before buying Narcan to ensure you are making a cost-effective purchase.

How To Get Narcan For Free

In some locations or situations, certain people may be able to get Narcan at no cost. Some states, communities, or local organizations will provide Narcan free to those who meet specific criteria, or even sometimes to anyone. These programs are particular to locations, governments or groups, and someone wanting Narcan at no cost will need to look up services that provide free Narcan in their area.

Why Narcan Is Not A Substitute For Medical Care

Narcan should never be used instead of seeking medical care. Narcan’s effects are very temporary, wearing off long before an opioid overdose will. Opioid overdoses can be fatal. This means someone who suddenly recovers after being given Narcan will still need to get medical treatment for an overdose, even if they no longer have overdose symptoms.

Additionally, someone who needs Narcan has an underlying problem that must be addressed. They may:

  • Be prescribed too high a dose of opioids
  • Be attempting to commit suicide using opioids
  • Not understand how to give themselves the correct amount of opioids
  • Have an opioid addiction they cannot control

Whatever the reason, someone who has overdosed on opioids will need to talk with a healthcare professional to ensure it does not happen again.

More FAQs About Narcan

How long does Narcan stay in your system?

Narcan is used quickly by the body, only having a lasting effect for about 30 minutes in most people. Opioid overdoses can last several hours; this is why a single dose of Narcan is not enough to save someone overdosing on opioids. They’ll likely need emergency medical care.

Does Narcan work on fentanyl?

Narcan will work on any opioid drug, including fentanyl. Fentanyl is a very powerful opioid, so Narcan may have a shorter effect or need to be used at a higher dose for someone who has overdosed on fentanyl.

Who pays for Narcan?

Narcan is often paid for by the person using it, although some locations have government-funded or privately-funded programs to cover the cost of Narcan and make it more available. Health insurance programs may partially or entirely cover Narcan.

How does Narcan make you feel?

Using Narcan should not affect how you feel unless you have been using opioids. If you use Narcan after using opioids, you are likely to feel very uncomfortable and agitated suddenly.

Does Narcan get you high?

Narcan should not get you high. While Narcan is mixed with some medicines that may cause a high, it is mixed with these medicines to prevent abuse. Narcan will actually eliminate an opioid high when used.

Opioid Addiction Treatment in New Jersey

If you or someone you know believes they’ll need Narcan at some point, it can indicate a serious opioid addiction is present. Opioid overdoses and addictions can be fatal and often require professional medical help.

At The Recovery Village Cherry Hill at Cooper, we are dedicated to helping people in the Northeast overcome the dangers of opioid addiction. Located just 20 miles outside of Philadelphia, our state-of-the-art addiction treatment facility can provide you with the evidence-based treatment needed to safely overcome opioid addiction. Contact us today to learn how we can help you achieve a life free from addiction.


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Emergent Devices. “Narcan Nasal Spray 4g.” 2022. Accessed June 2, 2022.

Substance Abuse and Mental Health Services Administration. “Naloxone.” April 21, 2022. Accessed June 2, 2022.

Lynn, Rachael Rzasa & Galinkin, JL. “Naloxone dosage for opioid reversal: cur[…]linical implications.” Therapeutic Advanced in Drug Safety. January 2018. Accessed June 2, 2022.

Substance Abuse and Mental Health Services Administration. “SAMHSA Opioid Overdose Prevention Toolkit.” 2018. Accessed June 2, 2022.

Medical Disclaimer: The Recovery Village aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

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