Choosing Between Naloxone and Naltrexone: What You Need to Know

One of the primary interventions for addiction treatment entails two main medicines that have emerged as vital tools in combating the opioid crisis: naloxone and naltrexone. While they have similar names and purposes, the substances are entirely different regarding their mechanisms of action. If you are here to know the difference between the two substances, you have come to the right place. Understanding the differences between naloxone and naltrexone is crucial for healthcare providers and individuals seeking treatment options. This article aims to provide a comprehensive overview of these medications, including their uses, mechanisms of action, side effects, and factors to consider when choosing between them.

What is Naloxone?

Naloxone, often sold under the brand name Narcan, is an opioid antagonist medication. This means that it is primarily used for the reversal of opioid overdose. If the system is overwhelmed with opioids, naloxone intends to restore the brain working to avoid damage.  

It works by rapidly binding to opioid receptors in the brain, displacing opioids and reversing their effects. Naloxone is commonly administered via intramuscular injection, intranasal spray, or intravenous infusion, depending on the severity of the overdose and available resources.

While it is an indispensable resource to counter opioid addiction, it is not a long-term solution for opioid use disorder (OUD). It is also very important to instantly seek the medical help after dispensing naloxone as the effects only last for a maximum of 90 minutes and the risk of overdose still remains. 

Uses

The primary purpose of naloxone is to rapidly reverse the effects of opioid overdose. It is considered a life-saving intervention in emergencies where an individual's breathing is compromised due to the opioid overdose.

The effects that are counters include: 

• Respiratory depression
• Sedation
• Loss of consciousness

Emergency medical responders, law enforcement officers, and individuals at risk of opioid overdose routinely carry naloxone. Any bystander or a person with no medical background can use it because naloxone is quite handy.

Mechanism of Action

When it comes to opioid receptors, naloxone competes with opioids for binding sites while keeping the receptors from being activated. This is known as competitive antagonistic action. Naloxone quickly reverses respiratory depression and brings the central nervous system back to normal by reversing depression. This happens due to the removal of opioids from receptor sites. Depending on the dosage and method of administration, the effects usually become apparent minutes after ingestion and can last anywhere from 30 to 90 minutes.

Side Effects of Naloxone

While naloxone is generally well-tolerated, it can precipitate opioid withdrawal symptoms, especially in individuals who are physically dependent on opioids. These symptoms may include:

• Agitation
• Nausea
• Vomiting
• Sweating
• Increased heart rate

However, these potential risks of precipitating withdrawal are outweighed by the life-saving benefits of naloxone in reversing opioid overdose.

Understanding Naltrexone

Naltrexone is a longer-acting opioid antagonist medication that blocks the effects of opioids by binding to opioid receptors and preventing their activation. Unlike naloxone, which is primarily used for acute opioid overdose reversal, naltrexone is indicated for the long-term treatment of opioid dependence and alcohol dependence. It is available in oral and extended-release injectable formulations.

Uses of Naltrexone

Naltrexone is used as part of a comprehensive treatment program for individuals with opioid dependence or alcohol dependence. More often than not, it is included in the comprehensive medication-assisted treatment (MAT) program. 

It works by blocking the euphoric effects of opioids and reducing cravings. Due to these properties, naltrexone encourages abstinence and relapse prevention. Naltrexone is typically prescribed after undergoing detox. This is done to ensure that no residue of substance toxins is present in the body and withdrawal can be prevented.

Mechanism of Action

Naltrexone acts as a competitive antagonist at opioid receptors, similar to naloxone. However, unlike naloxone, which has a rapid onset and short duration of action, naltrexone has a longer duration of action, allowing for once-daily dosing in oral form or monthly dosing in extended-release injectable form. By blocking opioid receptors, naltrexone prevents the reinforcing effects of opioids and reduces the likelihood of relapse.

Side Effects of Naltrexone

Common side effects of naltrexone include nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fatigue. In rare cases, it may cause liver toxicity, especially at higher doses. However, this can be prevented by following the dose recommended by your doctor. Individuals should be monitored for signs of liver dysfunction while taking naltrexone, and liver function tests may be recommended periodically.

Choosing Between Naloxone and Naltrexone

You will not have to choose between naloxone and naltrexone as both of them usually serve different purposes and are not interchangeable.  Your doctor will usually consider some important factors before prescribing naltrexone. These may include, the individual's current opioid use, treatment goals, and medical history. 

You should keep naloxone with you if you or your loved one struggles with opioid use disorder, so that accidental or intentional overdoses can be prevented. Naloxone is primarily used for emergency overdose reversal and is essential for individuals at risk of an opioid overdose or those who may witness an overdose. Naltrexone, on the other hand, is indicated for long-term maintenance therapy and can help support sustained recovery from opioid or alcohol dependence.

For individuals seeking treatment for opioid dependence, naltrexone offers the advantage of long-term protection against relapse. It can be incorporated into a comprehensive treatment plan that may include counseling, psychosocial support, and other interventions. However, naloxone remains a critical tool in preventing opioid-related fatalities and should be readily available in communities where opioid misuse and overdose are prevalent.

Takeaway

Naloxone and naltrexone are both valuable medications in the treatment of opioid addiction, but they serve distinct purposes and have different mechanisms of action. Naloxone is used for emergency overdose reversal, while naltrexone is used for long-term maintenance therapy. 

Healthcare providers and individuals seeking treatment for opioid dependence should carefully consider the benefits, risks, and appropriate use of these medications to optimize patient outcomes and address the ongoing opioid crisis. You can understand your condition better if you are aware of the purpose of both drugs.