What is Naloxone?

And Where Do I Get It?

Naloxone preloaded syringe with an intranasal applicator attached. Andrew Burton / Getty Images

Naloxone is mentioned in the American Heart Association's 2015 CPR Guidelines as a medication that might be considered for some patients in cardiac arrest. To paramedics, that statement is about as obvious as saying, "the sky is blue." If you're not in the medical field, however, you might not be familiar with this very specific medication.


Naloxone has one function: reverse the effects of opioid substances.

It's officially known as an opioid antagonist. It doesn't have any other official uses yet, but it's been studied for use in treating other conditions, all of which are related to the way endorphins and opioids affect the nervous system.


Opioid medications are like keys to pain relief. Think of opioid receptors, found in the brain and nervous system, like locks. When you put the key in the lock and it fits, it turns off pain. It also turns off the desire to breathe, which is why we have naloxone, but I'll get to that in a minute.

Naloxone blocks opioid compounds from fitting into the receptors. In fact, naloxone fits so well, it actually kicks the opioid out of the way, not just stopping opioid effects from continuing, but actually reversing the effects that have already happened.


Naloxone is used overwhelmingly for opioid overdoses. If a patient takes too much of an opioid substance, he or she could lose consciousness and stop breathing.If no treatment is provided, an opioid overdose is often fatal.

Sometimes in the healthcare setting, naloxone can be combined with opioid medication to help control how much of a dose the patient gets. The naloxone is given to scale back the effects to too much opioid, often in an acute care setting where patients are being aggressively treated for pain.

Opioid medications and street drugs include:

  • Hydrocodone or dihydrocodeinone
  • Codeine
  • Fentanyl
  • Hydromorphone
  • Meperidine
  • Methadone
  • Morphine
  • Oxycodone
  • Oxymorphone
  • Heroin

There are other names, but these are the most common generic compounds.

Route of Administration

Naloxone is given as a shot or squirted into the nose (intranasal). As a shot, it can be given directly into the vein (intravenously), which is the fastest acting option, or into the muscle (intramuscular). Intranasal is the slowest acting, but can be done without medical training.

Side Effects

Technically, there aren't any known side effects of naloxone. It is a one-hit wonder, with only the one action. I say it technically doesn't have side effects because there are very real reactions that come with sudden reversal of opioid overdoses, especially in folks who are addicted.

In those who are addicted, sudden opioid reversal can lead to severe pain, vomiting, agitation, headaches, tremors, sweating (although many opioid overdose patients are already sweating) and in some extreme cases, seizures and heart rhythm changes.

Opioids also cause sphincter muscle constriction. You can see it in the eyes of the overdosed patient (that's not a metaphor; their pupils will be very small). Naloxone reverses the effects of opioids, which means it relaxes the sphincter muscles. In the eyes, that leads to bigger pupils.

In other sphincters, it leads to loss of bowel and bladder control. Naloxone often triggers incontinence in severe overdose patients who've been taking opioids for a long period of time.

Where to Find It

Naloxone is officially a prescription medication, but that might be changing soon. Currently, it's on every paramedic level ambulance in the United States and in most of the world. In some cities, it's provided free of charge in needle exchange programs.

There are some places around the U.S. where the police carry naloxone for opioid overdoses. These programs were originally designed to provide quick response for heroin overdoses, but the proliferation of prescription opioids has led to a need for naloxone in other settings.

Some pharmacies have begun selling naloxone over the counter as an intranasal prepackaged medication.

Continue Reading