Unlocking the Science: How Long Does Naltrexone Block Alcohol?

Let’s face it: scaling back on alcohol use, or eliminating it entirely, is no easy feat. Especially for those of us who have developed regular drinking habits or developed a physical dependence on alcohol, breaking free from this toxic substance can be challenging. 

While behavioral treatments, support groups, and therapy are beneficial for treating alcohol misuse, medications can sometimes bolster their effectiveness. Naltrexone in particular is a medication proven to help people reduce cravings and get sober.

In this post, we’ll explore what naltrexone is and how it works. We’ll also suggest more treatment options that can be used alongside naltrexone. Let’s get started!

What Is Naltrexone?

Also known as Vivitrol, naltrexone is one of the most popular medications for moderate to severe alcohol use disorder (AUD). It can be taken as a daily pill or monthly as an injection.

Naltrexone was first invented in 1963 and approved by the FDA in 1984 for the treatment of heroin addiction. A decade later, it was approved for treating alcohol misuse after finding that it mediated the effects of alcohol, leading to reduced alcohol cravings and relapse occurance. 

Since then, multiple studies have touted its effectiveness. In fact, a recent study found that naltrexone significantly reduces binge drinking among men with mild to moderate alcohol use disorder. 

Additional studies have shown that combining naltrexone with counseling led to a significant reduction in heavy drinking among participants compared to counseling alone. These findings demonstrate the crucial role that naltrexone can play as part of a comprehensive treatment plan for alcohol misuse.

How Does Naltrexone Work?

Understanding how naltrexone combats alcohol misuse takes us on a fascinating journey into the human brain, specifically the opioid system that is part of our brain's complex reward pathway. This system plays a pivotal role in our experience of pleasure and satisfaction, and it’s one that substances like alcohol cleverly manipulate.

Alcohol stimulates the brain's reward pathway, releasing chemicals that create feelings of pleasure and euphoria. This stimulation triggers our opioid receptors, which results in the sense of satisfaction that makes drinking so appealing. This pleasure-reward feedback loop can encourage repeated alcohol use, ultimately leading to misuse or dependence.

This is where naltrexone comes in. Naltrexone is an “opioid antagonist.” In simplest terms, an opioid antagonist obstructs the opioid receptors in the brain. It's like a key that fits into a lock but doesn't turn it. It's there, it fits, but it doesn't activate the lock. By doing this, naltrexone blocks the euphoric effects and feelings of intoxication, letting us reduce our drinking or even halt it entirely.

When administered, naltrexone attaches itself to the opioid receptors in the brain. This attachment creates a barrier, preventing substances like alcohol from accessing these receptors and triggering the release of pleasure-inducing chemicals. So, even if we consume alcohol, the expected rewarding effects are diminished or entirely absent because naltrexone is blocking our brain’s access points. When naltrexone is working in our body, consuming alcohol is no longer neurochemically rewarding.

It's important to note that while we can use naltrexone for alcohol cravings, it doesn't cure alcohol dependence — there's more to overcoming alcohol misuse than just managing the physical cravings. But by disrupting the reward mechanism typically associated with alcohol consumption, naltrexone can provide a supportive, effective tool in the overall treatment plan.

How Long Does Naltrexone Block Alcohol?

Now that we have a better understanding of what naltrexone is and how it works, we can turn to the next question: how long does naltrexone last? It depends on what form of the drug we’re taking. For instance, oral naltrexone lasts between 24 and 72 hours, while naltrexone injections can last for about a month. This means that we can experience reduced alcohol cravings for a few days if we’re taking the pill and for about a month if we’re injected with it. 

Just like alcohol and other drugs, naltrexone is processed by our liver. However, how quickly we process naltrexone depends on multiple factors, including our age and overall level of health. For instance, older people tend to process medications slower than younger people. And our body might have a harder time processing naltrexone if we have an underlying organ disease. 

So, how long does it take for naltrexone to work? Naltrexone begins to work the day that we take it, whether as a pill or injection. People typically begin experiencing relief from alcohol cravings within an hour or two of taking it.

Naltrexone Side Effects

Naltrexone is generally well tolerated and has minimal side effects. Plus, it’s not an addictive medication, so there is no risk of abuse. With that in mind, here are some of naltrexone’s common side effects:

• Nausea, vomiting, chills
• Diarrhea or constipation
• Headache, dizziness, ringing in the ears
• Muscle or joint pain
• Reduced appetite 
• Trouble sleeping 
• Anxiety or restlessness 
• Bruising, itching, tenderness, or swelling at the site of injection

In rare cases, naltrexone produces more serious side effects: 

• Increased blood pressure or heart rate
• Changes in liver function, liver failure or acute hepatitis
• Depressed mood or suicidal thoughts 
• Severe allergic reactions
• Pneumonia

When Should You Start Taking Naltrexone?

Doctors recommend that people with severe alcohol misuse wait until signs and symptoms of acute alcohol withdrawal have subsided before taking naltrexone. In other words, it’s generally advised to wait until the detox process is complete before starting naltrexone. This helps prevent severe withdrawal symptoms or side effects. 

Research shows that naltrexone works best for people who have already stopped drinking for at least 4 days when they begin treatment. People may experience fewer medication side effects (particularly nausea) if they are abstinent from alcohol when they begin taking naltrexone. 

Experts also recommend using naltrexone as part of a comprehensive treatment plan for alcohol misuse. By including it in a treatment regimen, people struggling with alcohol misuse can develop other tools to help them remain committed to sobriety once they stop taking naltrexone. 

Naltrexone is generally tapered off after about 3 to 6 months. However, healthcare professionals might recommend staying on it for at least one year, as some research indicates that when naltrexone is stopped, the benefits are lost. There are no known problems associated with long-term use of naltrexone, as it is a safe and effective medication when used as directed. 

What Form of Naltrexone Should You Take?

As we’ve learned, naltrexone can be prescribed as either an oral tablet or an injection. Only a medical professional can help us determine the route of administration and dose appropriate for our personal situation.

Typically, a doctor will prescribe a 25 mg oral tablet of naltrexone as a test dose to ensure we can tolerate the medication. If we tolerate it well, the dosage can be increased to 50 mg daily. Taking naltrexone tablets with food may decrease nausea or stomach upset, which is a common side effect of the medication. 

If a doctor prescribes an injection, the dose is usually 380mg given intramuscularly once a month (every four weeks). These injections are given by a doctor, nurse, or pharmacist. 

What Should You Avoid While Taking Naltrexone?

Since naltrexone is designed to help reduce alcohol cravings, it’s unsurprising to learn that we should avoid drinking alcohol while taking it. We should also avoid using illegal drugs and taking opioid pain medications (such as codeine, hydrocodone, oxycodone, or morphine) while taking naltrexone. This is because naltrexone blocks opioids’ effects, so if we try to overcome this blocking effect by taking a large amount of opioids, we may overdose or experience serious injury, coma, or death. Some cough syrups contain opioid pain medication, so discuss all medicine you’re taking with your doctor or pharmacist. 

Furthermore, pregnant women shouldn’t take naltrexone. While the effects of naltrexone on the fetus are unknown, animal studies indicate there could be some behavioral alterations and early fetal loss. Similarly, while the effects of naltrexone on babies are unknown, breastfeeding while taking the medication is not recommended since it can pass into the breast milk.

Additional Treatment Options for Alcohol Misuse

Since naltrexone should be used as part of a more comprehensive treatment plan for alcohol misuse, it’s important to look at other treatment options we can pursue. Here are 4 effective options that can be used in combination with naltrexone:

Join a 12-step program or other support group. Alcoholics Anonymous (AA) is one of the most common alcohol misuse treatment options. Support groups allow us to spend time with others facing similar problems, providing advice on staying sober and reducing our sense of isolation. Studies show that the social connection provided by these groups helps us build confidence in our own ability to avoid alcohol in social situations and supports our sobriety.

Try behavioral therapy. Individual, group, and/or family therapy can help us identify the root causes of our substance misuse, repair damaged relationships, develop skills to stop or reduce use, and deal with triggers that might cause us to relapse. Cognitive behavioral therapy (CBT) is a particularly effective tool, and it’s one of the many types of therapy for substance misuse. 

Go to residential treatment or “rehab” facilities. Both inpatient and outpatient treatment centers provide intensive treatment for substance misuse. Choosing which one largely depends on the severity of our condition. Inpatient facilities are more intensive, requiring people to stay at a special facility for 30 to 90 days to receive treatment such as detox, therapy, and medication. During outpatient treatment, people attend set rehab appointments during the week but still reside at home. 

Consider alternative treatments. Alternative treatments like acupuncture aim to restore balance in the body and have been shown to reduce cravings and withdrawal symptoms. They’re based on the concept that our health is determined by the balanced flow of life energy, "qi" (pronounced "chee"), throughout our bodies. One popular method is auricular acupuncture, which involves inserting needles into specific points on the ear. This form of acupuncture has been commonly used for substance use disorders since the mid-1970s.

While these are just some of the treatment options for alcohol misuse, research indicates they’re quite effective. Alcohol misuse can be a complex, complicated matter. By taking a holistic approach and combining different treatment options, we’re better equipped to get healthy and maintain sobriety.

The Bottom Line

Naltrexone is an effective medication for treating alcohol misuse and reducing alcohol cravings. It works by blocking the opioid receptors in our brain, preventing alcohol from triggering the release of feel-good chemicals like dopamine. Combined with other treatment options like behavioral therapies, peer support, and lifestyle changes, naltrexone can help us effectively manage alcohol misuse and support our journey toward a healthier, happier life. 

If you want to quit drinking but don’t know where to start, consider trying Reframe. We’re a neuroscience-backed app that has helped millions of people reduce their alcohol consumption and develop healthier lifestyle habits.