What Does NARCAN® Work On? A Complete Guide to What Naloxone Can and Can't Reverse

NARCAN® is one of the most important emergency medications available today -but there's a lot of confusion about what it actually does and doesn't work on. Can it reverse an alcohol overdose? What about cocaine, meth, or benzodiazepines? And what happens when multiple drugs are involved?

Understanding what drugs NARCAN® works on could be the difference between an effective response and a dangerous delay. Here's the complete, honest picture.

What Does NARCAN® Do?

NARCAN® is the brand name for naloxone - an opioid antagonist. It works by rapidly binding to opioid receptors in the brain and blocking the effects of opioids, restoring normal breathing within minutes in someone experiencing an opioid overdose.

According to the CDC, NARCAN® is a life-saving medication that can reverse an overdose from opioids including heroin, fentanyl, and prescription opioid medications when given in time.

Critically, NARCAN® has no harmful effect on someone without opioids in their system. If you give it to someone who hasn't taken opioids, nothing happens. This means when in doubt, give it. The risk of not giving it is far greater than the risk of giving it unnecessarily.

What Does NARCAN® Work On?

NARCAN® works on all opioids - both legal and illegal. According to NIDA, this includes:

• Heroin - NARCAN® reverses heroin overdoses reliably, typically with one dose

• Fentanyl - NARCAN® works but often requires multiple doses due to fentanyl's extreme potency

• Prescription opioids - oxycodone, hydrocodone, codeine, morphine, methadone, tramadol

• Synthetic opioids - including carfentanil and other fentanyl analogues

If the drug is an opioid - NARCAN® can reverse it. That's the simple rule.

Does NARCAN® Work on Alcohol?

No. NARCAN® does not work on alcohol overdose. Alcohol affects the central nervous system through entirely different mechanisms than opioids - it does not bind to opioid receptors, so naloxone has no mechanism to counteract it.

If someone is experiencing alcohol poisoning, NARCAN® will not reverse it. Call 911 immediately - alcohol poisoning requires emergency medical care focused on airway management, oxygen, and fluids.

The exception: If someone has consumed both alcohol and opioids - a common and dangerous combination - NARCAN® can still reverse the opioid component, which may help stabilize their breathing. But it will not address the alcohol itself. Emergency medical help is still essential.

Does NARCAN® Work on Meth?

No. Methamphetamine is a stimulant. It works in the opposite way to opioids, speeding up the central nervous system rather than depressing it. NARCAN® is an opioid antagonist and has no mechanism to counteract what meth does in the body. There is currently no FDA-approved medication that reverses a meth overdose the way NARCAN® reverses an opioid overdose.

The critical exception: According to the CDC, cocaine and methamphetamine are increasingly being mixed with fentanyl - often without the user knowing. If someone appears to be overdosing on meth but fentanyl is also present, NARCAN® can still reverse the fentanyl component. This is why giving NARCAN® when any overdose is suspected is always the right call - it cannot hurt, and if fentanyl is involved, it can save a life.

Does NARCAN® Work on Cocaine?

No - not directly. Cocaine is a stimulant, not an opioid, and NARCAN® has no effect on a cocaine overdose on its own. A cocaine overdose causes elevated heart rate, high blood pressure, and abnormal heart rhythm - none of which are reversed by naloxone.

The critical exception: Fentanyl is now commonly found mixed into cocaine often without the user's knowledge. In these cases, what looks like a cocaine overdose may actually involve fentanyl too. NARCAN® should still be given if an overdose is suspected, because if fentanyl is present, it can reverse that component and potentially save the person's life.

Does NARCAN® Work on Benzos?

No. Benzodiazepines - including Xanax®, Valium®, Klonopin®, and similar medications  are not opioids. NARCAN® will not reverse a benzodiazepine overdose. Benzos affect GABA receptors in the brain, not opioid receptors, so naloxone has no mechanism to counteract them.

A benzo overdose requires emergency medical care. Call 911 immediately.

The exception: Benzodiazepines are frequently used alongside opioids, and this combination significantly increases overdose risk. If someone has taken both benzos and opioids, NARCAN® can still reverse the opioid component  which may be enough to restore breathing and buy time for emergency services to arrive.

Does NARCAN® Work on Xylazine?

Not directly - but give it anyway. Xylazine (known on the street as tranq) is a veterinary sedative, not an opioid. NARCAN® cannot reverse xylazine on its own.

However, xylazine almost never appears in the drug supply alone, it is virtually always mixed with fentanyl. The CDC and DEA both recommend giving NARCAN® whenever an overdose involving xylazine is suspected, because reversing the fentanyl component restores breathing and buys critical time for emergency services.

For a complete guide to xylazine and how to respond, read our full breakdown: [Tranq Dope - What It Is, Why It's Dangerous, and What to Do]

What Drugs Does NARCAN® Not Work On?

To summarize clearly - NARCAN® does not work on overdoses from:

• Alcohol

• Cocaine (unless fentanyl is also present)

• Methamphetamine (unless fentanyl is also present)

• Benzodiazepines (unless opioids are also present)

• Xylazine (unless fentanyl is also present)

• Cannabis

• Hallucinogens

In all of these cases - call 911 immediately, regardless of whether NARCAN® is given.

The Fentanyl Contamination Rule

Here's the practical reality that changes how to think about all of the above: fentanyl is now present in a wide range of street drugs. According to NIDA, deadly doses of illicit fentanyl can be mixed into or sold as heroin, cocaine, or counterfeit pills - often without the user's knowledge.

This means that what appears to be a cocaine overdose, a meth overdose, or even a benzodiazepine overdose may actually involve fentanyl too. In any suspected overdose situation regardless of what drug you think was taken  the CDC recommends giving NARCAN® if it's available. It cannot harm someone without opioids in their system, and if fentanyl is involved, it can save their life.

When in Doubt - Give NARCAN® and Call 911

The most important takeaway from this guide is simple: NARCAN® should never replace calling 911. It is a bridge - a tool that buys critical time for emergency services to arrive. Whether NARCAN® works on the specific drug involved or not, professional medical care is always required.

According to the CDC, a potential bystander was present in nearly 43% of overdose deaths in 2023. That means almost half of all overdose deaths happened with someone nearby who could have acted. Having NARCAN® within reach and knowing when to use it puts you in a position to be that person.

Be Ready for Whatever You Encounter

NARCAN® works on opioids. A naloxone carry case keeps it on you - so when it's needed, it's there. → Get nCase Lite

Quick Reference - What Does NARCAN® Work On?

Knowledge Matters. So Does Having NARCAN® On You.

Knowing what NARCAN® works on is the first step. The second is making sure it's with you. nCase Lite is designed to help keep your naloxone within reach every day. 

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Note - nCase Lite is a carrying case only – naloxone not included. Always follow the manufacturer's instructions for storing and using your medication. nCase Lite is not a medical device. In an emergency, call 911. NARCAN® is a registered trademark of Emergent Operations Ireland Limited. nCase Technologies is not affiliated with any pharmaceutical manufacturer.