How Does Narcan Work? Naloxone Mechanism Of Action And Uses

Last Updated: December 18, 2019

Authored by Nena Messina, Ph.D.

Naloxone is a potentially life-saving drug for those abusing opiates. Narcan use has saved many lives, and the more awareness there is of the drug, the better the results will be. It is vital that people are familiar with Narcan uses and best practices before relying on the drug.

When To Use Naloxone

There is only one situation when to use Narcan: opiate overdose (OD). Naloxone is a medication meant to reverse the effects of taking too much opiates, especially as they impact the respiratory system. The Narcan classification is opiate antagonist, which means it prevents euphoric feelings and can counteract other effects of opiates.

Considering when to administer naloxone, it should be as soon as possible after overdosing signs are observed. First, the user or those around them should call 911; then they should opt for Narcan use. If the person has stopped breathing, CPR may be needed to restart the respiratory system while the medication does its work. As soon as EMTs arrive, everyone should make room for them and let them take the steps necessary to save the overdosing individual.

Narcan For Opioid Overdose

While it has some off label uses, what Narcan is used for in the majority of cases is reversing opioid overdose. However, it may not effectively reverse the OD of all drugs. Users should know with which substances it is effective before obtaining and using Narcan.

naloxone for opioid overdose

What Drugs Does Narcan Reverse?

When it comes to the drugs Narcan works on, they are almost exclusively opioids. Naloxone is used for these ODs because of how it interacts with opioid receptors.

Drugs Narcan does work on include:

  • OxyContin
  • Vicodin
  • Codeine
  • Dilaudid
  • Demerol
  • Lorcet
  • Lortab
  • Norco
  • Heroin
  • Fentanyl
  • Methadone

Does Narcan Work On Cocaine?

Cocaine is not an opioid; it is a stimulant, while opioids are depressants. As such, Narcan for cocaine overdose is not effective. It is possible that if an overdose is being caused by combining cocaine with opioids, naloxone use could reverse part of the OD effects, giving the person time to get to a hospital and be treated, but it will not impact the effects of cocaine on the body.

Does Narcan Work On Fentanyl?

Fentanyl is an opioid and a very powerful and dangerous one at that. Narcan does reverse fentanyl OD in some cases. However, there is Narcan resistant fentanyl, so users should not consider naloxone to be a foolproof method or a reason to abuse fentanyl without fear. It is also an extremely potent opioid, so naloxone may be able to only partially reverse its effects, leaving the user is a significant danger.

Does Narcan Work On Meth?

No, methamphetamine is a stimulant of the amphetamine class. Naloxone is not used in the treatment of meth overdoses because it is not effective. If a meth overdose is caused by combining meth with an opiate, Narcan may help a bit to curb the OD but will not address the effects meth produces.

does narcan work on meth

How To Administer Narcan

How to use naloxone will depend on the product form. Naloxone administration varies based on if the user is taking it intranasally with naloxone nasal spray or through injection. It is important that anyone who either abuses opiates or is around those who do knows how to use both methods of administration. While there are other ways it can be used, including intravenously, these methods are only meant to be used in hospital settings.


Even not knowing these rules, how to administer nasal Narcan is pretty intuitive, making it an ideal form of the medication. However, some users may prefer injectable methods.


Injectable Narcan is equally as effective as nasal versions, but it may work slightly faster. Some users prefer this method, while others are intimidated by the idea of Narcan administration through injection. What is perhaps most dangerous about this method is that many people do not know where you inject Narcan. Based on films and television, they assume it is injected into the heart. However, this is not advisable as it can cause near instant death. How to give a Narcan injection depends on the product form, as there are syringe options, as well as an autoinjector.

Aside from the nasal spray option, the autoinjector is the easiest method for how to use naloxone. Naloxon can also be administered intravenously, intraosseously, and subcutaneously. However, all these three methods are practiced in medical settings only.

Narcan Training

Naloxone training is classes with kits and online videos that aim to teach people how to administer Narcan safely and correctly. With these classes at kits, users learn how to identify when someone needs naloxone administered, a proper injectable Narcan dose, and how to use all product forms of the drug properly. Users are also told about how to contact emergency services and what to tell them when they call.

narcan training

In most cases, free Narcan training is offered. However, there are some paid programs, especially when they offer a kit for the user to keep. Anyone worried about themselves or loved ones overdosing on opiates, or even those who just live in an area with heavy abuse, should look into Narcan training near them to be prepared to possible emergencies.

How Does Narcan Work?

While what Narcan does is reverse the effects of an opiate OD, most users do not understand how it accomplishes this. Users should understand how naloxone works before taking the medication. Central to this is the Narcan mechanism of action.

Naloxone Mechanism Of Action

In truth, the naloxone mechanism of action is not fully understood. What is known is that it occupies opioid receptors, blocking them to opiate medications. It specifically can remove opiates from these receptors and occupy them itself, which is how it reverses overdose effects, such as respiratory depression. While this is vital to those attempting to reverse an OD, side effects of naloxone can make its use uncomfortable, and users should always seek medical attention after taking it.

naloxone mechanism of action

How Fast Does Narcan Work?

When administered intravenously in a hospital setting, naloxone effects begin in as little as one minute. At-home forms of administration take a bit longer for the effects to kick in. Both injected nasal versions take about two to three minutes to work.

How Long Does Narcan Last?

How long naloxone lasts depends on how it was taken. When administered intravenously, it wears off in about 30 minutes, sometimes less. If used intramuscularly or intranasally, the naloxone duration of action is about 90 minutes. This is equal to roughly how long naloxone blocks opioid receptors.

Narcan Contraindications

Before taking the medication, people should be aware of naloxone contraindications. It is possible the user stands to face a greater risk by taking the medication than avoiding it. Contraindications for Narcan, however, are extremely limited. Only those known to be allergic to ingredients in the medicines are told to avoid it.

Anyone who has contraindications for Narcan but does use opioids should look into alternatives. In addition to giving them access to needed medication, it may be cheaper than the naloxone cost.

Getting Clean From Opiates

Having Narcan on hand is not a solution to addiction. Only the correct rehabilitation program in the drug center can help. Users worried about overdose or who have experienced one should contact a drug rehab facility to get the treatment they require.

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Published on: June 19th, 2019

Updated on: December 18th, 2019

About Author

Nena Messina, Ph.D.

Nena Messina is a specialist in drug-related domestic violence. She devoted her life to the study of the connection between crime, mental health, and substance abuse. Apart from her work as management at addiction center, Nena regularly takes part in the educational program as a lecturer.


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