Naloxone Guide: Dose, Definition, and Side Effects

Medically Reviewed

Each year, the opioid epidemic sees a new death toll that shatters records. For the last two decades, opioid death rates have risen steadily. Since 2010, heroin overdose deaths have skyrocketed, with each year having a larger toll than the last. In 2016, over 42,000 people died due to an opioid overdose, which means 116 people died every day.

In some U.S. counties, opioid overdoses make up the vast majority of the emergency ambulance calls. Emergency responders are often overwhelmed with calls and struggle to keep up with the people who are in need of their help. However, there is a drug that has become a vital tool for paramedics and has already saved countless lives. Naloxone is a drug that stops opioid overdose in its tracks. To an onlooker, the drug may appear to bring people back to life as the drug allows a patient to start breathing normally after opioids like heroin have suppressed their respiratory system.

Is the drug the answer to the rising overdose death toll or is it just a temporary fix? In this guide, you’ll learn how naloxone works to reverse the effects of an overdose, how it’s saving lives, and why it’s ultimately just another tool in much bigger problem.

Context: The Opioid Epidemic

The opioid epidemic is the phrase used to describe the exponential growth of opioid addiction and overdose in the U.S. and all over the world. The increase in opioid use has a number of possible causes. Studies have shown that the majority of people addicted to opioids started with prescription pain relievers like oxycodone. Some become addicted after receiving legitimately prescribed opioids but many start with illegally obtained prescription drugs.

According to The American Society of Addiction Medicine, four in five heroin users start out by misusing prescriptions opioids. As of 2015, chronic opioid painkillers were primarily obtained through prescriptions or by stealing drugs from health care providers at 43.7 percent. However, the rate of people who are using heroin first is quickly growing. According to a Washington University study, only 8.7 percent of people began an opioid addiction with heroin. By 2015, that number increased to 33.3 percent.

The Influence Of The Cartels

There is a growing availability of heroin. The Department of Drug Enforcement tracks the activity of transnational criminal organizations (TCOs) in the United States. Mexican cartels make up a majority of drug trafficking in the U.S. and they are the chief importers of cocaine, methamphetamine, heroin, and other opioids. Their sphere of influence was once confined to the southwestern regions of the U.S., but they have expended trafficking routes all over the mainland from Seattle to New England.

The Sinaloa Cartel is the TCO with the widest reach in the U.S., with dozens of offices and distribution points in cities across the country. They operate mainly at wholesale levels and sell bulk shipments to local street gangs. They move significant amounts of heroin into the U.S. every day, and they have recently become the country’s number one supplier of fentanyl, a deadly opioid that is cheaper and easier to make than both heroin and prescription pain relievers.

The Rise Of Fentanyl

Fentanyl is an opioid that’s 100 times more powerful than morphine and 50 times more powerful than heroin. Because of its potency, fentanyl is often used to cut or improve weak heroin. Heroin is often diluted to stretch profits, sometimes at multiple points of the distribution process. The end result is a weak product on the street level. For users that are tolerant to purer heroin, a cut product is noticeable. To keep customers happy while increasing profits, dealers can add fentanyl to the mix to dramatically increase the drug’s effect. However, this process creates a dangerous situation for the user.

Through cutting and mixing in other drugs, the proper dosage for any given user is unknowable. There is no way for the average user to how much heroin they can handle without overdosing. If you buy heroin from a dealer and achieve the desired high with a 35 mg dose, the same dose may kill you when your dealer gets a new batch. Each hit is a gamble.

Plus, fentanyl is extremely potent even at the microgram level. Any attempt to eyeball or guess at the proper dosage is likely to result in overdose. Plus, it has a 92 percent transdermal bioavailability. In other words, it can be absorbed into the bloodstream through the skin so effectively that it would only be eight percent more effective if you had injected it directly into a vein. That makes it dangerous to even handle.

With the rise of fentanyl and other synthetic heroin analog, the opioid epidemic has dramatically worsened over the past few years. Over 20,000 of the total 64,000 drug overdose deaths were related to fentanyl.

The exponential rise in availability of opioids and subsequent addiction has built up seemingly unstoppable momentum in the opioid epidemic. Meanwhile, as resources and attention go toward curbing the carnage of opioids, meth, cocaine, and alcohol use is quietly increasing as well. The need for a solution to curb the growth of opioid addiction and overdose is important now more than ever. Many hope that naloxone will be a catalyst that sparks a turn of the tide in the fight against opioids.

What Is Naloxone?

Naloxone is a medication used to treat opioid overdoses, especially in emergency situations. The drug is typically administered via injection into the muscle or vein of someone in withdrawal. However, in some cases, it can be sprayed into the nose. It’s sold under the brand name Narcan, and it’s primarily used by paramedics and EMTs but in some counties, police officers carry it for emergencies.

Naloxone was first patented in 1961 and was approved by the FDA for the treatment of opioids 10 years later. It wasn’t until 1996 that kits were distributed to people who were not medically trained. According to the U.S. Centers for Disease Control and Prevention, 26,463 overdoses were reversed by naloxone kits between 1996 and 2014. Though it’s a drop in the bucket compared to the overall overdose deaths during that time period, it’s an encouraging number of potentially saved lives nonetheless. Plus, the availability of the medication is growing and more states and counties are distributing it to emergency responders and citizens alike. Today, it can be obtained from a pharmacy without a prescription in 46 states.

Naloxone is relatively cheap, especially since the patent expired and generic brands have become available. In the United States, naloxone is classified as a prescription drug, but it’s not a controlled substance and states have allowed pharmacies to sell it over the counter. In many places, you can pick up the lifesaving drug at any corner store.

How Opioids Work

To understand Naloxone, it’s important to first understand how opioids affect the human brain and body. When you take an opioid, it quickly attaches to both the presynaptic and postsynaptic neurons that are transmitting pain signals and hinder pain signaling. This means that your nerve cells are stopped from sending pain signals to your brain and you feel analgesia (pain relief) and euphoria. We have yet to find any chemicals that so effectively stop pain.

If you take opioids regularly, your brain will begin to adjust to the introduction of increased neurotransmitters and the foreign chemical. First, this causes tolerance to build up.

Your brain will require more of the opioid to achieve the same effects because your body has gotten used to them. Next, your brain will become chemically dependent on the drug to maintain normal brain chemistry.

Finally, your brain will learn that opioids make you feel good and will continue to seek it out. Opioids release dopamine, which causes euphoria that lights up your reward center, like tasting good food or crawling into a warm bed after a long day. In the same way your brain learns to repeat those positive behaviors, it will learn to repeat opioid use through cravings and impulses.

Why Do We Still Use Opioids?

If opioids are so addictive, why are they still prescribed so widely? You’d think that since the number of opioid overdoses has continued to increase since the 1990s, we would be more hesitant to prescribe it. However, according to the CDC, the prescription of opioid pain relievers has almost quadrupled between 1999 and 2014. In 2016, 214,881,622 opioid prescriptions were issued in the United States.

Advocates for opioid use often point out the fact that, compared to the overall number of prescriptions, only a small number of people (around 8 to 12 percent) become addicted. Many of those who become addicted abused opioids or acquired them illegally from friends or family members. Still, the incredible availability puts many people who have heightened risk factors for addiction in harm’s way. Some people become addicted after legal, legitimate use.

The problem is that opioids are possibly the most effective pain relievers we have. Surgeries, cancer, injuries, and a host of other diseases and disorder cause acute or chronic pain and opioids stop pain dead in its tracks.

Naturally Receptive to Opioids

The human body has built in mechanisms that allow opioids to fit like a glove when it comes to attaching to receptors. The reason is that our bodies make their own opioids called endorphins. These endorphins are released for a number of reasons, one of which is to manage pain. Opioids like morphine were discovered to be more potent than the body’s natural solution. The don’t just work in the brain, but at every point along the pain trail from the original site of pain to your brains learning response.

Opioids work in three different pain areas:


Your body has different types of receptors all over the body that can detect temperature, pH, and pain. Pain receptors are called nociceptors and they are located in your skin, organs, muscle, and bones. They are designed to send messages to the brain to stop doing whatever is hurting you and to avoid doing it again.

Dorsal Root Ganglion

Pain signals travel up peripheral nerves (that connect nociceptors to the spine) and into the dorsal root ganglion. This is the part of the spinal cord that’s responsible for relaying sensory messages.


Once pain reaches your brain, many sections of it get involved, including the somatosensory cortex and the hypothalamus.

Learning Center

The limbic system and thalamus respond to pain by teaching you not to engage in pain full activities. In some cases, the response is so strong, phobias or psychological trauma develops.

Opioids are involved in all of these functions by slowing or stopping pain signals from being transmitted or receiving transmissions. Even in the learning process, opioids release dopamine to soften the brain’s response to pain and helps you avoid negative psychological repercussions.

Since opioids are so effective in treating pain, doctors are hesitant to stop or slow prescription. Plus, research looking into alternatives for pain, especially chronic pain, is a slow process.

How Naloxone Works

Naloxone counteracts the effect of an opioid overdose within minutes of administration and saves the life of a person from overdosing on heroin, prescription pain pills, and synthetic opioids. When an overdose occurs, opioids are binding to so many receptors that the brain slows down even essential functions. At this point, you don’t just feel relaxed and euphoric, your brain slows down or turns off regulatory signals that control breathing. You may also lose consciousness during overdose. Without intervention, overdose victims can suffer brain damage, hypoxia, coma, or death. Opioid overdose causes over 100,000 deaths globally.

Naloxone; however, can reverse these symptoms by rushing to the source of the problem: the opioid receptors. Opioids like morphine are opioid receptor agonists, which means they bind to the receptor and activate it. In this case, activating an opioid receptor means slowing down certain functions. Naloxone is an opioid receptor antagonist and it’s very efficient when it comes to binding to receptors. When it’s administered, it quickly binds to receptors and blocks opioids from attaching. As an antagonist, naloxone doesn’t activate the receptors it binds to. Essentially, it takes up the parking spot but it doesn’t get out of the car.

From an outside perspective, naloxone can appear to bring people in opioid overdose back to life. The drug takes effect within two minutes when it’s administered intravenously and five minutes when it’s injected into the muscle. During that time a person can go from an unconscious or catatonic state and shallow breathing to breathing normally and sitting up. In some cases, the naloxone can induce withdrawal symptoms as it abruptly stops the opioid effects.

How Long Does Naloxone Stay In Your System?

Naloxone has a relatively short biological half-life. A drug’s half-life refers the length of time it takes for the chemical to be reduced to half of its initial activity. Drugs are processed through the body’s cleaning system (the liver and the kidneys) but some drugs are harder to clean out than others. Half-life can also refer to the length of time a drug takes to halve its original concentration in the blood. By the time a substance reaches the end of its half-life, it typically loses its potency. It doesn’t necessarily mean that the half-life directly correlates to the duration of action. Heroin, for instance, has a three-minute half-life but its effects can last for hours. However, half-life does affect a drug’s ability to resist attempts to counteract it.

Naloxone’s half-life puts it at a disadvantage to opioids with longer half-lives like morphine and fentanyl when it’s taken intranasally or transdermal. A person who overdoses on an opioid with a longer half-life than naloxone can recover from dangerous respiratory suppression symptoms for an hour and then begin to overdose again when the medication wears off.

Think of it like a battle. Heroin, with its short half-life, is like a small fighting force. They may still attack a town and do a lot of damage which leads to effects that last for hours. But when naloxone comes in to defeat it and remove it from the receptors, the town is saved. Heroin is then filtered out of the body. However, morphine, with a long half-life, is like a large army. They can come into a town, do a lot of damage just like the smaller army. When naloxone arrives, it binds to receptors and stops overdose for a while, but then but the larger army outlasts them. When naloxone is filtered out of the body, morphine can continue to wreak havoc.

Still, naloxone gives people time to get to seek medical attention during an overdose. In many cases, a second dose of naloxone is administered once they arrive at a hospital. The chemical reinforcements, continue to counteract the opioid while the body is filtering it out.

Can Naloxone Be Abused?

When opioids are present, naloxone works to counteract the opioid receptor agonism but it doesn’t cause the receptors to activate. When it’s taken when opioids aren’t present, there has very little effect in the body at all. On its own, there is very little reason, recreational or otherwise, to take naloxone.

Federal drug scheduling in the U.S., which examines a drug’s potential for abuse, classifies it as a prescription drug. That means, from a regulatory standpoint, naloxone has some potential for abuse. On the state level, many governments have decided to lower its regulation level to an over the counter drug, which means that it doesn’t need to be prescribed to be dispensed.

Naloxone Side Effects

When it’s used to reverse an overdose, it can induce withdrawal symptoms. As the medicine pushes opioids off of their receptors and blocks the effects, the euphoric effects are stopped abruptly. It can be like waking up from a pleasant dream to an air horn and the worst flu you’ve ever had. Though it can save the person’s life, the situation can be painful and jarring. Side effects can include:

Naloxone has a number of adverse effects that are much less common, but it has been reported to affect a number of systems. However, the following side effects happen in only 10 to less than 1 percent of cases:

  • Cardiovascular System – Hypotension and hypertension can happen and has been seen in up to 10 percent of cases. Arrhythmias are even less common at one percent or less. Cardiac arrest is very rare but may be possible in 0.1 percent of cases.
  • Nervous System – Dizziness and headache can happen, especially when withdrawal is triggered. Tremors may occur in up to 1 percent of cases. And seizures are very rare, in about 0.1 percent of cases.
  • Respiratory System – Respiratory issues are very rare but pulmonary edema, or a buildup of fluids in the airways, may occur in less than one percent of cases.

Why is Naloxone Controversial?

A medication that helps reverse an overdose sounds like a solid win in the fight in the opioid epidemic, but it is surrounded by its fair share of controversy. Here are some of the major debate points:

Harm Reduction

Naloxone is considered a harm reduction method of addiction treatment. Though it doesn’t facilitate the use of drugs directly like needle exchange and prescription heroin, it does offer a safety net to people who engage in risky drug use. Harm reduction is always a controversial subject from methadone maintenance to sex education. Will people stop doing harmful behaviors if you help make harmful behaviors a little less harmful? Harm reduction generally doesn’t stop addiction but it does help avoid overdose.

Risk Compensation

One of the new emerging points in the naloxone debate is a phenomenon known as risk compensation. This is when perceived safety emboldens greater risks. For example, consider injuries in rugby and in football. They are both full contact games, but rugby players wear a lot less protective padding. People who run and tackle each other in shorts and a polo must get injured a lot more than people in a suit of foam armor, right? In reality, both sports have their fair share of bruises, broken bones, and serious injuries, but football has more serious concussions and a higher injury rate overall.

Why? The average person isn’t going to run full speed and make head to head contact with another full-grown man-mountain, but in a helmet and pads you may be willing to get a little more physical. It’s not just a football phenomenon either, people wearing seatbelts drive faster, skydivers take more risks as safety gear improves, and skiers with helmets go faster.

Because of this, people are concerned the same thing will happen with naloxone. There is a significant fear that if opioid users have a get-out-of-overdose-free card in their back pockets, they are more likely to take risks when it comes to drug use. In fact, one study suggests that the phenomenon is already happening. Researchers found that the increasing access to naloxone has led tomore opioid related crime and emergency room visits.

The jury is still out though. The opioid epidemic and overdose rates have been steadily skyrocketing for the last few years. As naloxone is growing in popularity, other forces, like the increasing availability and ubiquity of fentanyl might be counteracting its positive effects.

Who Can Get Naloxone?

redlands california opioid detoxThe increasing availability of naloxone is a key part of its effectiveness. When it’s in the hands of emergency responders, it can be administered as soon as first responders arrive. However, some areas are hit hard by the opioid epidemic and emergencies can get multiple overdose calls simultaneously. The need for quick action is paramount in an overdose, especially in the case of opioids which suppress breathing. Though it is officially scheduled as a prescription-only drug, every state has some provisions that make it easier to obtain. In most states, Naloxone is carried by emergency responders and can be administered in emergencies without a prescription. In many states, it can be purchased over the counter by lay people.

Even if you don’t use opioids and you’re not a medical professional, you can still obtain naloxone in many areas if you suspect that you may come into contact with an overdosing person. Keep in mind that naloxone won’t work on other types of overdose like cocaine or alcohol poisoning. If someone in your family is struggling with an opioid addiction, you may be able to keep some of the drug on hand. However, naloxone is a temporary fix for addiction. The best course is to deal with the problem at its source.

Where Naloxone Falls Short

Naloxone is an effective cure for overdose. That means that the epidemic is over right? The problem is solved. Many news outlets reported that naloxone would be a cure for the overdose epidemic. However, the overdose antidote has been available for years and the overdose epidemic is worse now than ever. The truth is that there is no cure for addiction currently. Naloxone can save lives, but it doesn’t stop addiction. People who receive naloxone still have intense cravings and the compulsion to use again. In many cases, patients are treated with naloxone several times to reverse overdose and they continue to use.

Still, it’s undeniable that naloxone saves lives. Opioid overdose is deadly and the debate over the socioeconomic and statistical value of naloxone doesn’t mean much when you or someone you know stops breathing because of an overdose and there’s a substance that can bring them back from the brink. If nothing else, naloxone gives people the opportunity to find long-lasting treatment when they would otherwise not make it through an overdose.

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