Narcan (naloxone) is an over-the-counter (OTC) medication that treats opioid overdose. Its mechanism of action is to quickly block opioids in your system. The effectiveness of this drug may vary based on how much opioids have been taken.

Narcan is used to reverse the effects of an opioid overdose.

What is opioid overdose?

Opioids are very strong pain relievers. Taking opioids at a higher dose or more often than your doctor recommends can lead to opioid overdose. Taking opioids in these ways is called opioid misuse, and it can lead to opioid use disorder.

Overdose can also happen if you take opioids at a dose that you used to take in the past, but after you’ve stopped using opioids for a while. (This type of overdose is caused by a loss of tolerance to opioids.)

Finally, it’s also possible to overdose on a prescribed dosage of opioids, but this isn’t common. However, this is more likely to happen if you take opioids in combination with alcohol or other drugs. These other drugs can include benzodiazepines (drugs used to treat anxiety disorders) or certain medications used to help you sleep.

In all of these cases, an overdose occurs when opioid levels in your body are too high, and they overwhelm your body. Opioid overdose can lead to possibly fatal symptoms, including:

Note: If you have pain that’s unmanaged with your current treatment plan, talk with your doctor about your concerns and all your options to manage your pain.

How opioid overdose can cause respiratory depression

One of the serious and possibly fatal symptoms of opioid overdose is respiratory depression.

This condition occurs when opioids attach to receptors (attachment sites) in the area of your brain that controls your breathing. When opioids bind to these receptors, they send a message to your lungs to breathe more slowly than usual. When opioid levels in your body are too high, your breathing can become dangerously slow or stop altogether.

How Narcan reverses opioid overdose

Narcan is an opioid antagonist (blocker). It works to reverse an opioid overdose by very quickly removing opioids from their receptors. This includes opioid receptors in the area of your brain that controls your breathing. This action “jump-starts” you to begin breathing again so that you can receive the oxygen that you need to survive.

Note: Even if someone wakes up after receiving Narcan, the overdose condition may happen again. This can occur if they took very high doses of opioids or if they took opioids that last longer in their body than Narcan lasts. It’s possible that a person will need multiple doses of Narcan to help prevent respiratory depression from happening again.

Narcan stays in your body and continues to work for about 2 hours.

Some people may need additional doses of Narcan when the medication’s level gets too low in their body. This may be the case when people overdose on very high doses of opioids, very strong opioids, or long-acting opioids.

However, even though Narcan will work for a while, you should call 911 right away after giving someone their first dose of Narcan.

For many people, emergency medical staff will arrive before the person needs their second dose of Narcan. But you should stay with the person who overdosed until medical staff arrives. This will allow you to monitor the person’s breathing and give them additional doses of Narcan. They may need additional Narcan doses if the overdose state reoccurs or if their first dose isn’t effective enough.

Narcan reverses an opioid overdose within 2 to 3 minutes after giving someone a dose. If the person doesn’t start breathing normally within that period of time, you should give them another dose of Narcan.

If you have questions about how Narcan works or how to use it, talk with a pharmacist or doctor.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.