Naltrexone Vs Naloxone: Difference Between The Two

Last Updated: June 24, 2020

Authored by Olivier George, Ph.D.

Reviewed by Michael Espelin APRN

Naltrexone and naloxone are medications used to combat the effects of opioid dependence in adults. Although it is a popular belief that the drugs are interchangeable, naloxone and naltrexone have a number of significant differences.

Naloxone Vs Naltrexone: A Brief Overview

Many people wonder what the difference between naltrexone and naloxone is since the drugs work in essentially the same way. The main difference between naloxone and naltrexone is the half-life of each medication. Narcan stops being effective after approximately an hour after it was administered. Naltrexone acts for a day in pill form and for as long as a month when it is given as an injection. Narcan is, therefore, reserved for emergencies, and Vivitrol is used for long-term opioid dependence treatment.

Drug Name Naltrexone Naloxone
Generic name Vivitrol, ReVia, Depade, others Narcan, Evzio, others
Generics availability Yes (oral) Yes (nasal spray)
Drug class Opioid antagonist Opioid antagonist
Prescription Prescription only Prescription only (available without prescription in emergencies)
Prescription form Pill
Oral liquid
Extended-release injection
Sublingual drops
Nasal spray
Treatment length Long-term
(treatment that extends beyond three months is the most beneficial)
Minutes to an hour
(used for emergency help to counter opioid overdose)
Lasting effects Rare but possible arthritis, liver damage, and respiratory infections Opioid withdrawal symptoms
Costs $136 for 30 tablets of naltrexone 50 mg
$500 to $1375 for one extended-release injection of Vivitrol 380 mg
$4,500 for auto-injector per two doses
$140 for nasal spray per two doses
$20-40 for generic naloxone per dose
Insurance coverage Yes Yes

Naloxone Vs Naltrexone Mechanisms Of Action

Both medications are opioid antagonists. They bind to opioid receptors in the brain and prevent other opioid substances from exerting any influence on a person. Naltrexone has a significantly longer action versus Narcan, which makes it suitable for long-term addiction treatment.

difference between naloxone and naltrexone

At the same time, naltrexone takes longer to act, which makes it unsuitable as first-line therapy for opioid overdose. It eliminates the pleasurable effects of opioid drugs, reducing the cravings over time. Narcan begins exerting an opioid-blocking influence within five minutes after the administration and can save a person’s life during an overdose. This rapid metabolism comes at a price: the medication becomes ineffective after approximately an hour after the delivery.

Naltrexone Vs Naloxone Uses

Naltrexone and naloxone are used to block the effects of opioid drugs and opiates. Narcan can prevent respiratory depression due to an overdose. Naltrexone prevents a person from experiencing any pleasure after ingesting an opioid drug, helping break the physical dependence on it.

Vivitrol: For Long-Term Use

The most significant difference between naloxone and Vivitrol is for how long naltrexone stays in one’s system. A Vivitrol injection lasts for a month, allowing for a slower release of the drug. It is designed to be durable to provide a longer action that requires less effort from a patient. Vivitrol is used in long-term rehabilitation to prevent a relapse, and it can’t be used when opioids are still present in the person’s body.

Naloxone: For Short-Term Use

Narcan is intended to start acting in 2 minutes after the administration. It is used to urgently block the effects of a substance when an opioid overdose is suspected. The drug can save a person’s life by instantly reversing CNS and respiratory depression. Narcan acts more rapidly versus Vivitrol, but it also doesn’t last long and wears off in 30 minutes to an hour after the delivery.

How To Use Naloxone Vs Naltrexone

Narcan vs naltrexone is relatively easier to use since it most frequently comes as a nasal spray. To administer the drug, a person should insert the tip of the nozzle in a victim’s nostril and press the plunger. Narcan can also be injected.

Naltrexone is available in pill form under the brand names ReVia and Depade. It is most frequently used as an injection of Vivitrol, however. On the one hand, tablets are extremely easy to consume and don’t require a person to possess any medical skills. On the other hand, it is easy to forget about the necessity to take a pill every day, which leads many patients to begin missing doses. Vivitrol injection requires the use of special needles with adjustable length.

naltrexone vs naloxone uses

Naloxone Vs Naltrexone Side Effects

Both medicines are opioid antagonists, and their side effects are quite similar. The main difference between naltrexone and naloxone side effects is the severity of symptoms. However, there are unique adverse effects of each drug.

Naloxone vs naltrexone side effects

Both drugs Naloxone Vivitrol
Nausea & vomiting
Dizziness & headache
Injection site infection or inflammation
Opioid withdrawal symptoms, although they might manifest more strongly with naloxone
Fever and sweating
Significantly increased heart rate and blood pressure
Cardiac arrhythmias
Coma and death
Potential liver problems

Naloxone vs Naltrexone: Costs And Insurance Coverage

Another difference between naltrexone and naloxone is the cost of each medication. The average price for 30 naltrexone 50 mg pills is about $110-130. The cost of a single Vivitrol injection can range from $500 to over $1300. All Medicare Part D and Medicare Advantage plans offer coverage for Vivitrol prescription. In addition, the manufacturer of Vivitrol offers a special savings program for patients with commercial health insurance and those who don’t have one. Buying naltrexone online can also significantly cut the expenses; however, it is slightly risky.

The cost of generic naloxone is on the average $30 per dose. The prices for the Narcan nasal spray range from $130 to $150 for two doses. An anti-overdose kit with injectable Narcan can cost up to $4500 for two doses. Naloxone is covered by all Medicare Part D and Medicare Advantage plans.

Naloxone And Naltrexone: Pros And Cons

Naltrexone Advantages And Disadvantages

Advantages Disadvantages
The medication can successfully prevent a relapse Vivitrol can only be used if a patient has been clean from any opioids for 7-10 days
A longer half-life (can be conveniently administered as a monthly injection) The injection site might get infected
It has fewer side effects than similar medications Vivitrol increases the risk of opioid overdose
Receiving a Vivitrol shot and drinking alcohol will not produce the same adverse reaction as the majority of similar medications Vivitrol cannot be used to counter an opioid overdose
Naltrexone addiction is not possible on the physical level

Naloxone Advantages And Disadvantages

Advantages Disadvantages
Naloxone can save a person’s life during an overdose Acute opioid withdrawal symptoms
Family members and other people can have access to naloxone in an emergency without a prescription Naloxone has significantly shorter action
Although Narcan and Vivitrol are both opioid antagonists, naloxone acts much more rapidly Potential seizures and cardiac problems

Naloxone And Naltrexone In Addiction Treatment

The main difference between naltrexone and naloxone is the purpose of each drug. Naloxone is used as an emergency medicine during an opioid overdose, while naltrexone is applied as a part of long-term addiction treatment. Narcan alone cannot be used as an alternative to naltrexone. However, together with buprenorphine, it is present in the drug called Suboxone and can be effective in withdrawal treatment. Vivitrol is generally cheaper than Narcan. To determine which medication is right for a person, it is crucial to consult with a doctor.

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Published on: June 7th, 2019

Updated on: June 24th, 2020

About Author

Olivier George, Ph.D.

Olivier George is a medical writer and head manager of the rehab center in California. He spends a lot of time in collecting and analyzing the traditional approaches for substance abuse treatment and assessing their efficiency.

Medically Reviewed by

Michael Espelin APRN

8 years of nursing experience in wide variety of behavioral and addition settings that include adult inpatient and outpatient mental health services with substance use disorders, and geriatric long-term care and hospice care.  He has a particular interest in psychopharmacology, nutritional psychiatry, and alternative treatment options involving particular vitamins, dietary supplements, and administering auricular acupuncture.


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