What is Narcan (naloxone): how it works, how to use it and where to get it
What naloxone is, how to give Narcan nasal spray step by step, why it can wear off, and how to get it free or without a prescription in five countries.
Narcan is a brand of naloxone, a medicine that quickly reverses an opioid overdose by pushing opioids off their receptors in the brain so the person can breathe again. In the US, Narcan nasal spray is sold without a prescription. To use it, spray one dose into a nostril, call 911, and give another dose after 2 to 3 minutes if the person doesn’t wake up.
At a glance
- The FDA approved Narcan 4 mg nasal spray for sale without a prescription on March 29, 2023, followed by RiVive (3 mg) in July 2023 and Rextovy (4 mg) in June 2026.
- Naloxone is active in the body for only 30 to 120 minutes, and the effects of most opioids last longer, so breathing can slow again (Health Canada).
- SAMHSA’s 2026 toolkit says naloxone does not cause harm if given to a person who is not having an opioid overdose.
- The maker’s suggested retail price for Narcan is $44.99 for a two-dose carton, and many programs give naloxone out free.
- Canada dropped the prescription requirement for naloxone in March 2016, and Australia has given it free with no prescription since July 1, 2022.
- SAMHSA puts the shelf life of naloxone nasal sprays at 36 to 48 months and injectables at 18 to 24 months.
What is naloxone and how does it work?
Naloxone is an opioid antidote. Health Canada describes it as a fast-acting medicine that temporarily reverses an opioid overdose by “kicking opioids off the receptors in your brain” and binding to those receptors instead. Opioids slow breathing, and naloxone lets it restart.
It works on opioids such as fentanyl, heroin, oxycodone, hydrocodone and morphine. The CDC says it can restore normal breathing within 2 to 3 minutes. The FDA says naloxone is not a controlled substance, and Victoria’s Better Health Channel describes it as non-intoxicating.
Narcan vs naloxone: what’s the difference?
Naloxone is the medicine. Narcan is one brand name for a naloxone nasal spray. Generic 4 mg naloxone sprays and other brands such as RiVive and Rextovy contain the same active ingredient, according to the FDA.
What forms does naloxone come in?
Naloxone comes as a ready-to-use nasal spray or as an injection. We checked which products are listed in the US in October 2026, using SAMHSA’s Overdose Prevention and Response Toolkit (revised 2026) and FDA approval announcements.
| Product | Form | Prescription needed? |
|---|---|---|
| Narcan, 4 mg | Single-use nasal spray | No, over the counter since 2023 |
| Generic naloxone, 4 mg | Single-use nasal spray | No, over the counter (first generic approved July 2023) |
| RiVive, 3 mg | Single-use nasal spray | No, over the counter since July 2023 |
| Rextovy, 4 mg | Single-use nasal spray | No, over the counter since June 2026 |
| Kloxxado, 8 mg | Single-use nasal spray | Yes |
| Naloxone vial, 0.4 mg/mL | Injection into a muscle | Yes |
| Zimhi, 5 mg/mL | Auto-injecting device, into a muscle or under the skin | Yes |
| Opvee (nalmefene), 2.7 mg | Single-use nasal spray | Yes |
SAMHSA notes that prescription products are also handed out through community distribution programs. It calls the injection vial the cheapest form of naloxone. Opvee contains nalmefene, a different reversal medicine that lasts longer in the body.
How do you use Narcan nasal spray?
These steps follow the FDA-approved Drug Facts label for over-the-counter Narcan. Other naloxone products come with their own directions, so follow the package you have.
- Check for an overdose. The person won’t wake up, is very sleepy or isn’t breathing well. Yell “Wake up!” and shake them gently. If they don’t wake up, go to step 2.
- Give the first dose. Peel open the package. Put the nozzle into either nostril and press the plunger firmly. Each device holds one dose.
- Call 911 right after the first dose. Outside the US, call your local emergency number.
- Wait 2 to 3 minutes. If the person doesn’t wake up, give another dose with a new device. Keep giving a dose every 2 to 3 minutes until they wake up. The label says it is safe to keep giving doses.
- Stay until the ambulance arrives, even if they wake up. Give another dose if they become very sleepy again. You may need every dose in the pack.
Rescue breaths and the recovery position
SAMHSA’s toolkit adds two steps while you wait for help. Support the person’s breathing, with rescue breaths if you know how. Once they are breathing, gently roll them onto their side into the recovery position so they don’t choke. The Narcan quick start guide also tells you to move the person onto their side after giving a dose.
Don’t take the spray out of its package or test it before you need it. Each device sprays only once.
Why can someone stop breathing again after Narcan?
Naloxone often wears off before the opioid does. Health Canada says it is active for only 30 to 120 minutes, and SAMHSA gives its half-life as 1.5 to 2 hours. When naloxone wears off, the opioid can slow the person’s breathing again.
That is why the person needs emergency care even if they wake up. The CDC advises staying with them until help arrives or for at least four hours. It also warns that more than one dose may be needed when stronger opioids such as fentanyl are involved. Nalmefene lasts much longer, with a half-life of about 11 hours, according to SAMHSA.
What are the side effects of Narcan?
The main side effect to expect is sudden opioid withdrawal in someone whose body is used to opioids. It happens because naloxone quickly blocks the opioids. The FDA, SAMHSA and the Narcan label list these symptoms:
- body aches and shaking;
- diarrhea, nausea or vomiting;
- a fast heartbeat;
- fever and sweating;
- runny nose, sneezing and goosebumps;
- anxiety or feeling angry.
The Narcan label says some people feel shaky, sweaty, sick or angry when they wake up, and that “this is to be expected.” SAMHSA says withdrawal can be “quite miserable” but is generally not life-threatening. Stay with them until help arrives, as the label directs.
Is it safe to give naloxone if you’re not sure it’s an opioid overdose?
Yes. SAMHSA says naloxone does not cause harm if given to a person who isn’t having an opioid overdose. The CDC says it won’t harm someone who is overdosing on drugs other than opioids, and the FDA calls it safe to use even when it’s uncertain whether opioids are present.
Naloxone won’t reverse alcohol, benzodiazepines or stimulants on their own, because Health Canada notes it only works if opioids are in the body. But other drugs are often mixed with fentanyl. The DEA’s 2025 threat assessment found fentanyl in one in four cocaine and one in eight methamphetamine lab submissions. If someone won’t wake up or is barely breathing, give naloxone and call for help. Our guide to the signs of an overdose covers other substances.
Who should carry naloxone?
SAMHSA says everyone should keep an opioid overdose reversal medicine on hand, especially people who use opioids or other drugs and their friends and family. The CDC names people who should carry naloxone and keep it at home:
- people with opioid use disorder;
- people taking high-dose prescription opioids, such as oxycodone;
- people who take opioids and benzodiazepines together;
- people who use illegal opioids.
Fake pills are another reason to carry it. The DEA warns that counterfeit pills are made to look like oxycodone, Percocet, Vicodin and Xanax, and may contain fentanyl. Our pill imprint search shows what a marked pill is supposed to be, but a matching imprint can’t prove a pill is real. Learn how to spot fake pills, and see our guide to opioid overdose for who is most at risk.
Our analysis: naloxone access in our five countries
We checked each country’s official sources in October 2026: the FDA and CDC, Puerto Rico’s Law 35 of 2021 and its Department of Health, Health Canada, Australia’s Department of Health and the Victorian Government’s Better Health Channel, and India’s National List of Essential Medicines 2022.
| Country | Prescription needed? | Free programs | Forms available | Typical cost |
|---|---|---|---|---|
| United States | No for Narcan, RiVive, Rextovy and generic 4 mg sprays (over the counter since 2023); yes for other forms | Community naloxone programs and most syringe services programs (CDC) | Nasal sprays (3, 4 and 8 mg), injection vials, Zimhi injection | Narcan: $44.99 per two-dose carton (maker’s suggested price). RiVive: $36 per twin pack (nonprofit maker’s starting price) |
| Puerto Rico | No. Law 35 of 2021 allows sale without a prescription, and FDA over-the-counter approvals apply | Free kits from the Department of Health’s Overdose Prevention Division (announced July 2025) | Same as the US | Same as the US |
| Canada | No. Health Canada changed naloxone’s prescription status in March 2016 | Free kits in some provinces and territories; kits at most pharmacies | Nasal spray (Narcan) and injectable kits | Free where provinces fund it; no national price found |
| Australia | No. Free without a prescription through the Take Home Naloxone program; Nyxoid is a Pharmacist Only Medicine | Take Home Naloxone at participating pharmacies and other approved sites (since July 1, 2022) | Nasal spray (Nyxoid), pre-filled syringe (Prenoxad), ampoules | Free through the program |
| India | No national rule found allowing sale without a prescription | No national take-home program found | Injection (0.4 mg/mL, on the essential medicines list) | No official price found |
Prices change and vary by store. Puerto Rico’s Law 35 of 2021 also requires health insurers to pay for naloxone dispensed without a prescription when the plan covers it. In Australia, the Take Home Naloxone program is open to people at risk of an opioid overdose and to their carers, friends and family.
Will you get in trouble for using naloxone or calling for help?
In the US, Puerto Rico and Canada, laws protect people who call for help at an overdose from some drug charges. We found no national law in Australia or India. These laws don’t cover every charge, so check the details where you live.
| Country | Law | What it covers |
|---|---|---|
| United States | State Good Samaritan laws; a 2021 GAO review found 47 states and Washington, DC had both Good Samaritan and naloxone access laws | The CDC says these laws protect people who are overdosing and anyone helping them from some criminal penalties. Details vary by state. |
| Puerto Rico | Law 35 of August 27, 2021 (Opioid Overdose Death Prevention Act) | Protects the person overdosing and the person seeking help from arrest and prosecution on certain drug charges when the evidence came from calling for help. A person who isn’t a health professional and gives naloxone in good faith isn’t liable. |
| Canada | Good Samaritan Drug Overdose Act, in force since May 4, 2017 | Protects the person overdosing, the caller and anyone at the scene when help arrives from simple possession charges. It doesn’t cover trafficking or outstanding warrants. |
| Australia | No national law found | – |
| India | No national law found | – |
How should you store naloxone, and does it expire?
The Narcan label says to store it at room temperature or in the fridge, between 36°F and 77°F (2°C to 25°C). Don’t freeze it, keep it out of heat above 104°F (40°C), and protect it from light. Health Canada also advises keeping the spray in its box until you need it.
Naloxone does expire. SAMHSA says nasal sprays usually last 36 to 48 months and injectables 18 to 24 months, so check the date and replace it on time. Research shows expired naloxone does not cause harm but may work less well, SAMHSA says. If an expired spray is all you have in an emergency, use it and call for help. Our guide on whether expired medicine is safe explains expiry dates in general.
Common questions
Do you need a prescription for Narcan?
Not in the US, where the FDA approved Narcan for sale without a prescription in March 2023. Puerto Rico’s Law 35 of 2021 also allows sale without a prescription. Canada has not required one since March 2016, and Australia gives naloxone free with no prescription through its Take Home Naloxone program.
How much does Narcan cost?
The manufacturer’s suggested retail price is $44.99 for a two-dose carton, though store prices vary. Many community programs, syringe services programs and health departments give naloxone out free, including Puerto Rico’s Department of Health, some Canadian provinces and Australia’s Take Home Naloxone program.
How long does Narcan last after you give it?
Health Canada says naloxone is active for 30 to 120 minutes, and most opioids last longer. Breathing can slow again when it wears off. Stay with the person until emergency help arrives, and give another dose if they become very sleepy again.
Can Narcan hurt someone who isn’t overdosing on opioids?
No. SAMHSA says naloxone does not cause harm if given to a person who isn’t having an opioid overdose, and the FDA says it’s safe to use when you aren’t sure opioids are involved. If someone won’t wake up or is barely breathing, give it and call for help.
Can you give Narcan to a child?
Yes. Health Canada says naloxone is safe for all ages, and the Narcan quick start guide covers adults and children. If a child may have taken an opioid medicine, give naloxone if they won’t wake up or aren’t breathing well, and call 911 right away.
Can you use expired Narcan?
SAMHSA says research shows expired naloxone does not cause harm, though it may be less effective. If an expired spray is all you have in an emergency, give it and call for help. Replace it as soon as you can, since nasal sprays usually last 36 to 48 months.
