Naloxone: Opioid Overdose Reversal Medication

Table of Contents


Naloxone is a medication that reverses the side effects of an opioid overdose.

This guide highlights how naloxone works and illustrates how the prompt administration of this opioid overdose antidote could be life-saving.

We want to help

Let’s setup a call and figure out the best treatment options for you or your loved one. Our detox specialists will get back to you immediately.

What is Naloxone?

Naloxone is an emergency medication that can rapidly reverse the effects of an opioid overdose. Opioids are a class of medication that includes heroin, fentanyl, morphine, codeine, hydrocodone, and oxycodone.

Classified as an opioid antagonist, naloxone binds to opioid receptors in the brain, blocking and reversing the effects of any other opioids in the system. When administered rapidly, naloxone can restore normal breathing when breathing has slowed or stopped due to opioid overdose.

Taking naloxone will have no effect if you do not have opioids in your system. The medication is not a treatment for opioid use disorder either – buprenorphine, methadone, and naltrexone are FDA-approved for this purpose.

There are two forms of naloxone approved by the FDA: an injectable and a prepackaged nasal spray.

 The branded form of naloxone spray called Narcan is the most dispensed brand of naloxone. The nasal spray is also available at Kloxxado and as generic naloxone.

Many different companies market injectable forms of naloxone. You can find these listed in the FDA’s Orange Book if you search for “naloxone injectable”. Naloxone is typically injected into the muscle, although a single-dose syringe (ZimhiTM) that’s prefilled and injectable under the skin is now approved by the FDA to help streamline administration.

Regardless of the dosage or form of naloxone that you use, make sure you receive training on how and when you should use the medication. Familiarize yourself with the product instructions and ensure that you check the expiration date.

Naloxone is also used as one ingredient of combination products that contain buprenorphine and naloxone – Suboxone, for instance. This medication is used for the treatment of opioid use disorder, relieving cravings and withdrawal symptoms.

What is Naloxone Used For?

Naloxone is used to reverse the effects of an opioid overdose. The medication targets the same opioid receptors in the brain that other opioids bind to, blocking their effects and reversing the respiratory depression associated with opioids, a condition that can be life-saving in the event of opioid overdose.

Naloxone can restore normal breathing within minutes in someone whose breathing has slowed due to opioid overdose. The medication can also be effective if breathing has stopped.

When administered to counter the effects of potent synthetic opioids like fentanyl, more than one dose may be required.

Naloxone nasal spray and naloxone injectables are considered safe and effective medications that trigger few side effects if used appropriately.

How Does Naloxone Work?

Naloxone counters the effects of other opioids by competing with those substances for a space on the brain’s naturally occurring opioid receptors.

By controlling and blocking those opioid receptors, naloxone can reverse the effects of respiratory depression triggered by opioids like heroin, oxycodone, or fentanyl. The effects of naloxone are only delivered if opioids are present in the system.

How to Administer Naloxone

What are the common administration routes for naloxone, then?

Naloxone can be administered via several routes including:

  • IV (intravenous
  • IM (intramuscular)
  • SC (subcutaneous)
  • IN (intranasal)

The method of administration will depend on the formulation of naloxone you have and the situation in which it is being used. 

Here are some general instructions for administering naloxone:

  • Call for emergency medical help immediately if you suspect an opioid overdose.
  • Check the person’s breathing and pulse. If they are not breathing or do not have a pulse, begin CPR (cardiopulmonary resuscitation), and continue until emergency medical help arrives.
  • If the person is breathing, but you suspect an opioid overdose, administer naloxone as soon as possible.
  • For the intranasal formulation of naloxone, remove the device from its packaging, and insert the applicator into one nostril, press the plunger to release the naloxone, and repeat the process in the other nostril.
  • For the auto-injector or pre-filled syringe formulation of naloxone, remove it from its packaging, and follow the instructions on the device.
  • For the IV or IM formulation of naloxone, administer it according to the instructions on the packaging or as directed by your healthcare provider.

After administering naloxone, monitor the person’s pulse and breathing, and deliver additional doses if necessary until emergency medical help arrives.

An image of woman who is using a tissue and looking upset, depicting someone who is experiencing Naloxone side effects

Are There Naloxone Side Effects?

Naloxone can reverse an opioid overdose for roughly 30 to 90 minutes. The elimination half-life of many opioids means that they remain in the system for much longer than that. This means that the effects of opioid overdose may still present after a dose of naloxone wears off. Stronger opioids like fentanyl may require more than one dose of naloxone.

While side effects from naloxone are rare, some people may experience an allergic reaction to the medication. Overall, naloxone is considered a safe, effective, and essential medicine. 

Those who are administered naloxone should be continuously observed until emergency medical care arrives. They should also be monitored for two hours after the last dose of naloxone to ensure that breathing does not slow or stop completely.

If you take naloxone and you are physically dependent on opioids, this may trigger the presentation of withdrawal symptoms that include:

  • Nausea
  • Vomiting
  • Sweating
  • Rapid heart rate
  • Tremors

Where to Get Naloxone

Most pharmacies carry naloxone in all 50 U.S. states. In some states, it is now possible to obtain naloxone from a pharmacist without a prescription from your physician.

You may also get naloxone from local public health groups, community distribution programs, and local health departments. Naloxone is available free of charge. 

The following individuals may obtain naloxone:

  • Someone using opioids
  • Outreach workers
  • Carers, friends, or family members of those using opioids
  • Sober living home manager
  • Someone working in a place where there is a risk of opioid overdose
An image of California Detox, an addiction treatment facility in Laguna Beach, CA.

Fight Opioid Addiction at California Detox’s Inpatient Rehab

Combat Addiction at California Detox

If you have developed an addiction to any type of opioids, from prescription painkillers to heroin and fentanyl, we can help you address this issue at California Detox in Laguna Beach.

Engage with our supervised medical detox program to streamline opioid withdrawal and mitigate the likelihood of relapse or complications derailing your recovery before it gets traction. Following a week or so of opioid detox, you can transition into one of the following treatment programs:

  • Residential rehab (inpatient program)
  • PHP (partial hospitalization program)
  • IOP (intensive outpatient program)
  • Dual diagnosis treatment program (for co-occurring disorders)
  • Virtual IOP (remote rehab program)

Whatever level of treatment intensity best suits your circumstances and opioid addiction, access individualized treatment that combines science-backed and holistic therapies such as: 

  • Psychotherapy
  • Medication-assisted treatment
  • Group therapy
  • Individual counseling
  • Family therapy
  • Holistic therapies
  • Aftercare

When you are ready to unchain yourself from opioid addiction, kickstart your recovery at California Detox by calling 949.694.8305 today.


Naloxone is typically only available with a prescription from a healthcare provider. Some states in the U.S. have now implemented policies that allow pharmacists to dispense naloxone without a supporting prescription. In those cases, naloxone may be available over-the-counter, but only in certain locations and under specific circumstances. The FDA reports that some naloxone products may be approvable for nonprescription use.
Naloxone is classified as an opioid antagonist. This means that the medication works by blocking the effects of opioids in the brain. Naloxone is not an opioid, and the medication does not produce the characteristic effects of opioids like pain relief or euphoria. Instead, naloxone is used to rapidly reverse the effects of opioids in the event of an overdose.


Request a Call