Is Vivitrol (Naltrexone) the Same as Narcan (Naloxone)?

For those with opioid dependence, or their loved ones, finding a treatment plan that can eliminate dependence or addiction and prevent a relapse is of the utmost concern. 

Various medications may block opiate receptors, and many of them often get confused or mistaken for each other. While they have similar results, these medications work differently due to various factors, including the length of use, urgency, drug interactions, and more.

Two commonly used (and commonly confused) anti-opiate drugs are Vivitrol (Naltrexone) and Narcan (Naloxone). Below, we explain the differences between these two medications so you can learn more about the available treatment options and find one that works for you or your loved one.

Are Vivitrol and Narcan the Same Thing?

Vivitrol (the brand name for Naltrexone) and Narcan (the brand name for Naloxone) are both opioid antagonists. It means they block the effects of opioids and other drugs like heroin from affecting the brain.

Both act on the opioid receptors, and they may have some similar side effects, including dizziness, nausea, nervousness, irritability, restlessness, weakness, or tiredness. However, they each have distinctive purposes and side effects of their own that we’ll cover in greater detail below.

Both Narcan and Vivitrol may interact with other drugs, particularly narcotic pain medications. 

Additionally, no one should embark on a Vivitrol or Narcan treatment program if there are still opioids or heroin in their systems, as it could lead to severe withdrawal.

What Are the Differences Between Vivitrol and Narcan?

Now that we’ve outlined the similarities between Vivitrol and Narcan, let’s go over the primary differences between the two opioid antagonists. 

The crucial differences are in the urgency and immediacy of use, the length of the effects, side effects, availability, chemical structure, drug interactions, and administration method.

Urgency of Use

The most critical distinction between Narcan and Vivitrol is the urgency of use and when to administer the medication. 

Knowing the difference could save someone’s life. 

Naloxone is used to reverse the effects of an overdose quickly. A person can administer it at a moment’s notice if someone is displaying signs of an overdose. 

Most commonly, Narcan is for treating opiate overdoses, such as reversing a fentanyl overdose. The medication is delivered via injection with printed instructions on the injector detailing proper use and step-by-step instructions for administering the drug.

On the other hand, Naltrexone is typically part of an ongoing treatment plan for opioid or alcohol use disorders. Vivitrol is a longer-term solution and is not intended for use in the moment of an overdose.  

Length of Effects

Narcan immediately affects the person who receives it, and the effects may last anywhere from 30-90 minutes in the body. This period usually allows the body to recover from most opiate abuse. Still, if someone has taken a large amount, they may need another Narcan dose after the 90 minutes have elapsed.

Vivitrol, on the other hand, is designed to be taken daily, usually in the morning, and can help people struggling with addiction suppress cravings. The injectable form of Vivitrol lasts even longer, up to 30 days. 

Side Effects of Vivitrol and Narcan

Naltrexone can cause appetite loss as well as aches and pains. It can also cause:

  • Diarrhea, constipation, or vomiting
  • Sleepiness or insomnia
  • Restlessness or irritability
  • Rash or muscle pain at the injection site

Common Naloxone side effects include:

  • Nervousness
  • Muscle weakness or achiness
  • Dizziness
  • Slight fever or chills
  • Headache, sneezing, runny nose


In some places, Narcan is available without a prescription in a drug overdose kit that anyone can get and learn how to administer if someone has overdosed on opiates. 

Naltrexone always requires a prescription.

Drug Interactions

There are a few Narcan interactions to know. The most crucial is that you should not take it if you are also taking morphine, oxycodone, buprenorphine, hydromorphone, or if you have renal or liver disease, septic shock, or CV disorders. This drug has also been shown to have mild interactions with at least 25 different drugs, so it’s wise to talk with your doctor or pharmacist about the other medications or products you use.

Anyone actively taking opiates or heroin should not take naltrexone, as it can potentially result in an overdose. You should also talk to your doctor before taking Vivitrol if you take narcotic pain medications such as codeine, buprenorphine, hydrocodone, methadone, morphine, oxycodone, or propoxyphene. Additionally, you should not use Vivitrol while taking narcotic drugs or alcohol. Finally, exercise great caution if you do anything that requires you to be alert when taking Vivitrol. 


While there are injectable options for both naloxone and naltrexone, each also has alternative administration methods. Naloxone administration typically employs an auto-injector or nasal spray. If injected, it should be on the thigh. If given via nasal spray, the person receiving the medication should lie on their back.

Naltrexone administration is by injection or oral ingestion as a tablet. The injection goes into the buttocks, while the tablet is fine to take with or without food, typically in the morning.


Are you or someone you love dependent on opioids? There are options that can help fight substance abuse both immediately and long-term. 

Vivitrol and Narcan are two of the most commonly used medications to fight opioid addiction. While they are both opioid antagonists and work within the body similarly, they have notable differences that you should be aware of, so you can understand the best times and situations to take either one.

Whatever situation you find yourself in, know that recovery and sobriety are possible. At the Master Center in Hampton, VA, we take a compassionate, people-first approach to help all of our patients begin the journey back to themselves. Learn more about the programs and services we offer, and discover if the Master Center can help you or your loved one. Reach out to our treatment centers at your convenience.