Medically Reviewed

Naloxone (Narcan): Uses, Administration, Side Effects, and Safety in Overcoming Opioid Overdose

4 min read · 9 sections
Naloxone is a medication approved by the U.S. Food and Drug Administration (FDA) that is used to quickly counteract the effects of an opioid overdose.1,2 This medication is available as a nasal spray (Narcan, Kloxxado) or an injectable solution1,3,4,5
What you will learn:
Naloxone uses
Side effects of naloxone use
When to use naloxone
How to use naloxone

What is Naloxone (Narcan)?

Naloxone is an opioid antagonist, meaning it binds to opioid receptors in the brain to displace and block the potentially lethal effects of any opioid agonist drug in the system, reversing the effects of an opioid overdose very quickly.1,2,4,5 However, the overdose reversing effects of naloxone may only be active for 30-90 minutes, while some opioid drugs can stay in your system for much longer. It is important to receive medical attention to ensure that overdose symptoms don’t return when the effects of naloxone wear off.1,2,4,5-7

Naloxone was first developed in the early 1960s and approved by the FDA in 1971, as an injection to reverse opioid overdoses.7,8 It has been in use by medical professionals for more than 50 years in hospitals and by emergency medical services.4,7,8 More recently, several forms of naloxone have been made more widely available for use without medical training.9 Narcan prefilled nasal spray was FDA-approved in 2015, with a generic version approved in 2019. Kloxxado, a higher dose of naloxone nasal spray, was approved in 2021.9 There are also injectable forms of naloxone that may be used in clinical settings or by emergency providers.1

In 2023, the FDA approved Narcan and RiVive nasal spray for over-the-counter, nonprescription use, recognizing that since naloxone is the standard treatment for opioid overdose, making it readily available in places like drug stores, convenience stores, grocery stores, gas stations, and online, could save lives.10,11

Uses of Naloxone

The main use of naloxone is to reverse symptoms of an opioid overdose.1,2,12 It can help breathing return to normal and return a person to consciousness after ingesting a dose of opioids that was too high. However, these effects are temporary.1,2,3,7

Naloxone can be used to reverse an overdose on any type of opioid, although you may need to use several doses for long-lasting or extremely potent opioids such as fentanyl.1,4 Kloxxado is a nasal spray that delivers a higher dose of naloxone to counteract overdose from opioids such as fentanyl.9 In its various formulations as an opioid overdose antidote, doses of naloxone can range from 2 mg to 8 mg per dosage. Repeat dosing may be needed in certain situations. However, if overdose symptoms aren’t reversed after receiving more than 10 mg of naloxone, other substances may be responsible for overdose symptoms.5,7,14

It’s important to note that while naloxone can quickly reverse an opioid overdose, it is not used as a treatment for opioid use disorder or for treating opioid withdrawal effects.1

How Do You Administer Narcan?

See our video on how to reverse an opioid overdose using Narcan.

Step 1: Identify signs of an overdose. Opioid overdose occurs when an individual takes enough of the drug to cause potentially potentially life-threatening symptoms, which may include:4,15

  • Loss of consciousness or the inability to be awakened.
  • Extremely small pupils (pinpoint-sized) or pupils that don’t respond to light.
  • Shallow breathing, slowed breathing, difficulty breathing, or making choking or gurgling sounds.
  • Blue-tinged, pale, clammy, or cold lips, fingernails, and/or skin on lighter skin-toned people. For those with darker complexions, the fingernails and lips may look gray or ashen.

If you suspect that you or someone else has overdosed on opioids, attempt to wake the individual by calling their name. If they fail to respond, rub your knuckles on their upper lip or the center of their chest. If they still fail to respond, follow these steps:4

Step 2: Call 911. An overdose requires immediate medical attention. Tell the dispatcher that someone is “unresponsive and not breathing.” Provide them with the address or a description of your location.

Step 3: Administer naloxone if it’s available. If using a metered nasal spray such as Narcan or ReVive, peel back the package and remove the nasal spray. Hold the nasal spray with your thumb on the bottom of the plunger and two fingers on the nozzle. Insert the nozzle into the individual’s nostril (either one) until your fingers touch the bottom of their nose. Press the plunger firmly to release the dose into their nose. If using another nasal spray or the injectable naloxone, follow the instructions on the package.16

If the individual does not start breathing within 2-3 minutes, administer a second dose of naloxone.

Step 4: Support the individual’s breathing. If you know how, provide rescue breaths. If you don’t have training, follow the instructions given to you by the 911 dispatcher. When breathing returns, gently turn the individual on their side with their top leg bent to support them in the recovery position.

Step 5: Stay with the individual. Remain with them until medical professionals arrive. Naloxone wears off after 30-90 minutes and overdose symptoms can return.

Side Effects of Naloxone Use

It is uncommon for people to experience side effects from naloxone, though there have been rare cases of pulmonary edema as well as allergic reactions or hypersensitivity to the drug.7

Opioid withdrawal symptoms can also occur if you have previously developed physiological opioid dependence and receive naloxone. Acute opioid withdrawal symptoms can include abdominal pain or nausea; feeling nervous, restless, or irritable; body aches; fever, chills, or goosebumps; diarrhea; feeling dizzy or weak; and runny nose or sneezing.2

In an emergency overdose situation, there should be no absolute contraindications to using naloxone. Hesitation to do so could result in a fatal overdose.7

Naloxone Safety and Availability

Naloxone is known to have an exceptionally high safety profile.1,4,6 No naloxone overdoses or deaths as a result of taking too much naloxone have been reported.4,6 If naloxone is given to someone who has no opioids in their system, the medication will have absolutely no effect on them. This is why administering naloxone is recommended, even if you aren’t sure that the person has overdosed on an opioid.1,3,4,6,12 The medicine hasn’t been shown to cause tolerance or dependence, and has no potential to be misused.4,6

For many years, naloxone was used only by hospital staff and emergency medical technicians. Access to this life-saving medication has been expanded in more recent years.2,4,7,8 Between 2012 and 2017, all 50 states had decriminalized the administration of naloxone by non-medical personnel. As of 2022, naloxone is currently available without a prescription at pharmacies in all 50 states, Washington D.C., and Puerto Rico.1,2,3,7,9 In many states, naloxone can be prescribed and dispensed to people who take prescription opioids or to those who have an opioid use disorder, the clinical term for an opioid addiction.9

Naloxone may also be available through other sources, including distribution programs within the community, Veterans Health Administration (VA), public health groups, or your local health department.1,3,9 There are other options if it isn’t covered by your insurance plan or if you don’t have health insurance.1,3 Cost assistance programs may be available through the drug manufacturer if you can’t afford the medication, and you may be able to get it free of charge in some locations.1,3

Is It Time for Rehab?

If you or someone you love has experienced an overdose resulting from problematic opioid use, you may want to think about attending a rehab program. This can be a wake-up call to make the changes you need to stop your substance use and get into recovery. Attending rehab can make a major difference in your life by addressing the root cause of your addiction, easing withdrawal symptoms, improving your coping skills, teaching you techniques to prevent relapse, strengthening your ability to communicate effectively, improving stress management skills, replacing substance use with healthy activities, developing a sober support network, and improving your overall health.17 Naloxone can save your life if you experience an overdose, but rehab can completely change your life when you are ready to stop your substance use.

Narcan FAQS

How Does Narcan Help?

Naloxone reverses potentially fatal respiratory depression caused by opioids. Since naloxone is an opioid receptor antagonist, it latches on to the opioid receptors, displacing and blocking opioids that are in the system. This allows naloxone to reverse the effects of opioids and restore normal breathing patterns in an individual whose breathing slowed or stopped.1,2,4

Does Narcan Only Work on a Person Who is Overdosing on Opioids?

Naloxone only works on opioid drugs in your system.4

Can Narcan Harm a Person if They Aren’t Overdosing?

Naloxone is not effective in the overdose effects of benzodiazepines, cocaine, stimulants, and other non-opioid substances. However, naloxone may still be effective in individuals that have taken a combination of opioids and other substances.4

Additionally, if someone is experiencing an overdose from a non-opioid drug or another medical emergency, such as a heart attack or diabetic coma, naloxone generally won’t have any effect or cause additional harm.4

Does Narcan Expire?

Yes, by law, all prescription medications have an expiration date. If you are in an emergency situation and have expired naloxone, you should still use it as many drugs are potent past their expiration date.

Where Can I Get Narcan?

You can get Narcan from your local pharmacy, a community-based distribution program, a local public health group, or your local health department.The FDA is working to make naloxone more readily available to individuals, families, first responders, and communities in order to help reduce fatal opioid overdoses.10 

Frequently Asked Questions

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