What Is Narcan (Naloxone)? How It Works and Where to Get It

Key Takeaways

• Narcan is the brand name for naloxone, a medication that rapidly reverses opioid overdoses
• Naloxone works by displacing opioids from brain receptors, restoring normal breathing within minutes
• It is effective against heroin, fentanyl, oxycodone, morphine, and other opioids but does not reverse overdoses from alcohol, benzodiazepines, or stimulants
• Narcan nasal spray is available over the counter at pharmacies nationwide without a prescription
• New Jersey’s Overdose Prevention Act provides legal protection to anyone who administers naloxone or calls 911 during an overdose

Naloxone: A medication classified as an opioid antagonist that binds to opioid receptors in the brain and reverses the life-threatening effects of an opioid overdose, particularly respiratory depression.

Narcan is the most widely recognized brand name for naloxone, a medication that can reverse an opioid overdose in minutes. When a person overdoses on opioids, their breathing slows dangerously or stops entirely. Naloxone displaces the opioid molecules from receptors in the brain, temporarily restoring normal respiration. The medication has no potential for abuse, produces no euphoric effects, and has been on the World Health Organization’s List of Essential Medicines since 1983.

What Narcan Is and How It Works

Opioid Antagonist: A substance that binds to opioid receptors without activating them, effectively blocking or reversing the effects of opioid drugs. Naloxone is the most commonly used opioid antagonist in emergency medicine.

Naloxone was first developed in 1961 and approved by the U.S. Food and Drug Administration (FDA) in 1971. It works through a straightforward pharmacological mechanism: naloxone has a higher affinity for mu-opioid receptors than most opioid drugs. When administered, it competes for those receptor sites and displaces opioid molecules that are already bound there.

Naloxone in Simple Terms

In plain language, naloxone kicks opioids off the brain’s receptors. The opioid is still in the person’s bloodstream, but it can no longer attach to the sites that control breathing. This is why naloxone’s effects are temporary, typically lasting 30 to 90 minutes. If the opioid in the person’s system outlasts the naloxone, respiratory depression can return. This is especially concerning with long-acting opioids like methadone or with fentanyl, which may be present in large quantities in body tissues.

The Mechanism: Blocking Opioid Receptors

Mu-Opioid Receptor: The primary brain receptor responsible for the pain-relieving, euphoric, and respiratory-depressing effects of opioid drugs. Naloxone’s binding affinity for this receptor is what makes overdose reversal possible.

When naloxone reaches the brain, it binds to mu-opioid receptors with greater strength than heroin, fentanyl, or prescription opioids. This competitive binding displaces the opioid and blocks further opioid activity. The result is a rapid restoration of breathing, typically within two to five minutes of administration. Because naloxone only affects opioid receptors, it produces no effects in people who do not have opioids in their system.

Which Drugs Does Narcan Work On

Opioids That Narcan Reverses

Naloxone is effective against all opioid-class drugs, including:

• Heroin — one of the most common causes of fatal opioid overdose
• Fentanyl and fentanyl analogs — the leading driver of overdose deaths in New Jersey and nationally, according to the CDC
• Oxycodone (OxyContin, Percocet) — widely prescribed and frequently involved in prescription opioid overdoses
• Hydrocodone (Vicodin, Norco) — another common prescription opioid
• Morphine — used in medical settings and sometimes diverted
• Methadone — a long-acting opioid used in treatment that can also cause overdose
• Codeine — less potent but still an opioid-class drug

With fentanyl, multiple doses of naloxone may be needed due to fentanyl’s extreme potency. The CDC has noted that fentanyl-related overdoses sometimes require two or more administrations of naloxone before breathing is restored.

What Narcan Does Not Treat

Naloxone has no effect on overdoses involving non-opioid substances. It does not reverse the effects of:

• Benzodiazepines (Xanax, Klonopin, Valium) — these require flumazenil, a different reversal agent
• Alcohol — alcohol poisoning is not opioid-mediated
• Stimulants (cocaine, methamphetamine) — stimulant overdoses involve different mechanisms entirely
• Sedatives and barbiturates — not responsive to opioid antagonists

In situations involving polysubstance use, naloxone will reverse the opioid component but will not address the effects of other drugs present. Emergency medical services should always be contacted regardless.

How to Administer Narcan

Nasal Spray Instructions

The Narcan nasal spray (now also available as the generic RiVive) requires no medical training. The steps are:

1. Peel back the packaging to remove the device
2. Hold the device with your thumb on the bottom of the plunger and two fingers on the nozzle
3. Tilt the person’s head back and insert the nozzle into one nostril
4. Press the plunger firmly to deliver the entire dose
5. If no response within two to three minutes, administer a second dose in the other nostril

The person may experience immediate opioid withdrawal symptoms upon waking, including agitation, nausea, vomiting, and rapid heart rate. These symptoms, while uncomfortable, are not life-threatening.

When to Call 911

Naloxone is a bridge to emergency care, not a substitute for it. The National Institute on Drug Abuse (NIDA) emphasizes that 911 should be called immediately in any suspected overdose situation, even if naloxone is available. The reasons are critical:

• Naloxone wears off in 30 to 90 minutes, and the overdose can recur
• The person may have other drugs in their system that naloxone does not address
• Medical professionals need to evaluate the person for complications including aspiration pneumonia

Where to Get Narcan in New Jersey

Pharmacies and Standing Orders

New Jersey has a statewide standing order issued by the Commissioner of Health that allows any pharmacy to dispense naloxone without an individual prescription. This means anyone — a person who uses opioids, a family member, a friend, a teacher, a coworker — can walk into a participating pharmacy and obtain naloxone.

Since 2023, the FDA approved Narcan nasal spray for over-the-counter sale nationally. It is available alongside other OTC medications at major pharmacy chains including CVS, Walgreens, and Rite Aid locations throughout New Jersey. Generic naloxone nasal spray (RiVive) is also available OTC at a lower cost.

Free Narcan Programs in NJ

The New Jersey Department of Human Services and the NJ Division of Mental Health and Addiction Services (DMHAS) fund multiple free naloxone distribution programs across the state:

• NJ Naloxone Distribution — local health departments distribute free naloxone kits along with training
• Prevention Coalition programs — county-level coalitions in all 21 NJ counties provide naloxone and education
• Harm reduction organizations — groups operating in Newark, Camden, Trenton, and other cities distribute naloxone at no cost
• Hospital emergency departments — many NJ hospitals provide naloxone kits at discharge to patients treated for overdose

The NJ Overdose Prevention Helpline can direct callers to the nearest free naloxone source.

New Jersey’s Good Samaritan Law

Legal Protections for Administering Narcan

Good Samaritan Law (Overdose Prevention Act): New Jersey’s law (P.L. 2013, c. 46) that provides immunity from certain criminal charges for individuals who seek medical help during a drug overdose, as well as for those who administer naloxone in good faith.

New Jersey enacted its Overdose Prevention Act to remove barriers that prevent bystanders from helping during an overdose. Under this law, a person who administers naloxone in good faith to someone they believe is experiencing an opioid overdose is immune from civil liability for any resulting injuries. This protection extends to laypeople, not just medical professionals.

Protections for Calling 911

The law also protects the person experiencing the overdose and the person who calls 911. Specifically, both parties receive immunity from arrest, charge, or prosecution for:

• Drug possession (personal use quantities)
• Being under the influence
• Certain drug paraphernalia charges

This legal framework was designed to address the documented reluctance among people who use drugs to call emergency services out of fear of arrest. According to data from the NJ Attorney General’s Office, Good Samaritan protections have been associated with increased 911 calls for overdose events.

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This glossary entry is part of our Addiction Treatment Glossary, a comprehensive resource covering key terms and concepts in substance use treatment. For related reading, see our pages on Narcan forms and administration methods and the differences between naloxone and naltrexone. To understand the broader opioid crisis driving naloxone demand, visit our guide to fentanyl addiction or review New Jersey overdose data and trends.