How Does Narcan Work?

Narcan, the brand name for the generic naloxone, is an FDA-approved medication that can reverse an opioid overdose.1 For someone who’s overdosed on opioids, the administration of this medication can mean the difference between life and death, as every minute is crucial.

This page will discuss what Narcan is, how it works, and how administering it can potentially save lives.

What is Narcan?

Narcan is a brand name for a pre-dosed, prefilled device containing naloxone, a medication that reverses the life-threatening effects of opioids in someone who is experiencing an opioid overdose. Narcan helps restart breathing due to opioid-induced respiratory depression.1 Narcan is designed for easy single-dose administration as a nasal spray into the nose, and as an injection that can be administered into the muscle or under the skin.2

Having naloxone available is recommended for those who are at risk for an opioid overdose, such as those who are prescribed high-dose prescription opioids, misuse opioids, use illicit opioid drugs such as heroin, and those who are prescribed or use opioids and benzodiazepines together.2 Additionally, those with loved ones who are high risk for opioid overdose can benefit from carrying and being trained to deliver naloxone, as they may be able to provide emergency assistance to a loved one if needed.

It is recommended for naloxone to be administered after calling 911 anytime an individual is suspected of experiencing an overdose, as this medication causes no harm to someone without opioids in their system.2

If you are uncertain of whether or not someone is experiencing an opioid overdose, there are three key signs to look for, known as the “opioid overdose triad:”3

  • Pinpoint pupils
  • Respiratory depression
  • Loss of consciousness

Again, if you are unsure if someone is overdosing on opioids, administer naloxone if you can, as doing so will not harm them regardless of what they are overdosing on.2

How Does Narcan Work?

Naloxone is an opioid antagonist, which means that it works by blocking the effects of opioids.1 It does this by attaching to opioid receptors and reversing and blocking the effects of opioids.1 Naloxone reverses slowed or stopped breathing caused by opioids and can restore breathing to its usual state within 2 to 3 minutes.2 More than one dose may be required, depending on how potent the opioid or how large a dose was taken. Administering naloxone as soon as possible after someone has overdosed is ideal, as the brain can be damaged the longer it is deprived of oxygen.

How Long Does Narcan Stay in the System?

Naloxone can reverse an opioid overdose for approximately 30 to 90 minutes.1 Many opioids, however, remain in the system longer than that.1 If the dose of Narcan wears off before the opioids do or if a more potent opioid was taken, the effects of an overdose can return.1 This is why it is important to stay with an individual who has overdosed until the person gets emergency medical attention from first responders, so additional naloxone can be administered or other steps can be taken to restore a person’s breathing.

Overdosing While on Narcan

While Narcan can be effective at restoring breathing and preventing overdose, it is important to understand that overdose is still possible even after taking Narcan.1

Multiple doses of naloxone are sometimes needed to make sure the person is out of danger of overdosing.1 People who have taken high doses of opioids or synthetic opioids like fentanyl, in particular, might require multiple naloxone administrations.4 This underscores the importance of calling 911 to get the person medical attention until the danger has passed and why you should stay with someone who has overdosed until help arrives.2

If breathing problems continue, Narcan can be given every 2–3 minutes.4 It is best to monitor the person for at least 2 hours after the last dose of naloxone to ensure that breathing does not stop again.1

It is important to note that for those with a physical dependence on opioids, the administration of Narcan or generic naloxone can trigger the onset of withdrawal symptoms in the body within minutes.1 Some symptomatic reactions someone can experience can include the following:1

  • Changes in blood pressure
  • Rapid heart rate
  • Nausea
  • Vomiting
  • Tremors

Despite this possibility, giving naloxone to someone who is overdosing is far more important than attempting to avoid these symptoms, as these symptoms do not cause death like overdose can.1

Where Can I Get Narcan?

Narcan or generic naloxone can be obtained in every U.S. state.2 Pharmacies are the most common places to obtain Narcan, and most states allow people to do so without a prescription.2 Public health programs, health departments, and needle distribution programs are also places where people can obtain Narcan or generic naloxone.2 Those who are prescribed high opioid doses can benefit by having their doctors prescribe them naloxone.2

Find out where to get Narcan in Mississippi.

Get Help for Opioid Dependence at Oxford Treatment

If you or a loved one is struggling with opioid addiction or misuse, contact our inpatient drug and alcohol rehab in Mississippi right now by calling . We will connect you with one of our compassionate addiction rehab admissions navigators who can answer all of your questions, including those about drug and alcohol rehab insurance coverage, rehab payment options, and the levels of addiction treatment we offer.

Do not wait any longer to reach out for the help you or your loved one needs. Call Oxford today to get more information. You can also get started on your recovery by verifying your insurance and filling out our


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