Narcan is a nasal spray used to reverse opioid overdoses. Its active ingredient, naloxone, works by knocking opioids off the receptors in your brain that control breathing, restoring normal respiration within minutes in someone whose breathing has slowed or stopped. In March 2023, the FDA approved Narcan as the first over-the-counter naloxone product, meaning you can buy it without a prescription at pharmacies, grocery stores, convenience stores, and online.
How Narcan Works
During an opioid overdose, the drug binds tightly to receptors in the brain and spinal cord that regulate breathing, pain, and sedation. Breathing slows dangerously or stops entirely. Naloxone has an even higher affinity for those same receptors than opioids do, so when it enters the body, it displaces the opioid molecules and blocks them from reattaching. This competitive binding is what makes the reversal so fast.
Narcan works against a wide range of opioids: heroin, fentanyl, oxycodone, hydrocodone, codeine, morphine, and other synthetic or prescription opioids. It does not reverse overdoses caused by non-opioid drugs like cocaine, methamphetamine, or benzodiazepines. If someone hasn’t taken opioids, Narcan has no effect on their body, which makes it safe to administer even when you’re unsure what substance is involved.
What Narcan Does Not Do
Narcan is not a treatment for addiction, and it doesn’t get someone high. It purely blocks opioid activity. It also won’t help with overdoses that don’t involve opioids at all. However, because many street drugs are now contaminated with fentanyl, Narcan is worth using whenever an opioid overdose is suspected, even if the person believed they were taking something else.
One important limitation: naloxone wears off faster than most opioids. The effects of a single dose typically last 30 to 90 minutes, while many opioids, especially fentanyl and long-acting prescription painkillers, remain active much longer. This means a person can slip back into overdose after Narcan wears off. That’s why emergency medical care is still necessary after every use.
How to Use the Nasal Spray
The over-the-counter version comes in a box with two 4-milligram nasal spray devices. Each device delivers one dose into one nostril. Here’s what to do if you suspect an opioid overdose:
- Call 911 first. Narcan buys time, but it’s not a substitute for emergency medical care.
- Open the packaging. Peel back the tab to remove the spray device. Don’t test or prime it beforehand.
- Position the person. Tilt their head back and support the neck with your hand.
- Administer the spray. Hold the device with your thumb on the plunger and two fingers on either side of the nozzle. Insert the nozzle tip into one nostril until your fingers touch the base of the nose, then press the plunger firmly.
- Wait two minutes. If the person doesn’t respond, use the second spray in the other nostril.
- Stay with the person. Monitor their breathing until paramedics arrive or they’re fully awake.
If the person isn’t breathing while you wait for Narcan to take effect, give rescue breaths and chest compressions: 30 compressions for every 2 breaths.
What Happens After It’s Given
When Narcan works, the person may wake up confused, agitated, or nauseated. In people who are physically dependent on opioids, naloxone can trigger what’s called precipitated withdrawal. This happens because the drug strips opioids from receptors all at once, throwing the body into withdrawal within minutes rather than hours. The most common sign is a rapid heart rate, which occurs in roughly 80% of cases. Nausea, vomiting, sweating, and muscle aches can follow.
Precipitated withdrawal is uncomfortable but not life-threatening. The person may want to use opioids again immediately to relieve the symptoms, which is another reason to stay with them and wait for emergency responders. The alternative, not giving Narcan, is far more dangerous: untreated opioid overdose can cause brain damage or death within minutes.
Fentanyl and Repeat Dosing
Fentanyl is significantly more potent than heroin or prescription opioids, and overdoses involving fentanyl sometimes require more than one dose of Narcan. Because naloxone works by competing for the same receptors, a larger amount of opioid in the system can require more naloxone to fully displace it. If the first spray doesn’t restore breathing within two minutes, use the second one. Emergency responders carry additional doses and can administer more if needed.
Where to Get It and How Long It Lasts
You can buy Narcan without a prescription at most pharmacies, and it’s increasingly stocked at convenience stores and gas stations. Many state and local health departments also distribute it for free. There are no federal age restrictions on purchasing it.
A sealed Narcan nasal spray has a shelf life of four years for newly manufactured products. Older stock may carry a three-year expiration date printed on the box. If your Narcan has expired and someone is overdosing, use it anyway. An expired dose may be less potent, but it’s better than no dose at all. Replace expired kits when you can, and store them at room temperature, away from direct sunlight.
Why It Matters for Non-Opioid Users Too
You don’t need to use opioids yourself to encounter an overdose. Fentanyl now contaminates a wide range of illicit drugs, and overdoses happen in homes, workplaces, public restrooms, and college campuses. Keeping Narcan accessible is similar to keeping a fire extinguisher in the kitchen: you hope you’ll never use it, but having it on hand can save a life in the minutes before professional help arrives.