Description

Naltrexone: A Clinically Trusted Medication for Alcohol and Opioid Use Disorders

Naltrexone has been a cornerstone medication in addiction medicine for several decades. Although it is not a cure-all, it consistently proves valuable in treatment plans for individuals living with alcohol use disorder (AUD) or opioid use disorder (OUD). When used responsibly—often alongside therapy, medical supervision, and behavioral support—it can significantly improve long-term recovery outcomes.

In clinical practice, we often see patients walk in with both hope and apprehension. Many have tried to quit multiple times and are searching for something dependable to help quiet cravings. Naltrexone is not about replacing one substance with another; rather, it helps the brain regain stability, supporting people as they rebuild healthy routines and reclaim a sense of control.

How Naltrexone Works in the Body

The Mechanism of Action

Naltrexone is classified as an opioid receptor antagonist. It binds strongly to the brain’s mu-opioid receptors, blocking the euphoric and reinforcing effects of opioids and reducing the reward response associated with alcohol consumption.

For alcohol use disorder:

• It reduces the “reward” signals alcohol produces.

• This helps lower cravings and decreases the likelihood of heavy drinking episodes.

For opioid use disorder:

• Naltrexone prevents opioids like heroin, fentanyl, or oxycodone from attaching to their receptors.

• Even if a person uses opioids while taking naltrexone, the expected high does not occur.

The National Institutes of Health highlights this mechanism in several studies examining opioid antagonists and relapse prevention strategies (example deep link:
https://pubmed.ncbi.nlm.nih.gov/25388618/).

Onset and Duration

• Oral naltrexone: begins working within 1–2 hours.

• Extended-release injectable naltrexone: reaches peak levels within several days and lasts about 4 weeks.

Clinicians often recommend starting with oral tablets to assess tolerance before transitioning to the long-acting injectable form.

Approved Therapeutic Uses

1. Alcohol Use Disorder (AUD)

The FDA approved naltrexone for alcohol dependence in 1994. A large body of clinical evidence—including meta-analyses funded by the NIH—demonstrates that naltrexone:

• Reduces heavy drinking days

• Lowers relapse risk

• Diminishes cravings

One frequently cited analysis can be found in the NIH’s clinical reviews (example deep link:
https://pubmed.ncbi.nlm.nih.gov/24779567/).

In practice, many patients report that alcohol loses its “pull” within the first few weeks. They often say it becomes easier to walk away from a drink that previously felt irresistible.

2. Opioid Use Disorder (OUD)

Naltrexone is also FDA-approved for the prevention of relapse in opioid use disorder—particularly after full detoxification. An important distinction: you must be completely opioid-free for at least 7–10 days before starting therapy.

The FDA’s prescribing information for naltrexone emphasizes this requirement to avoid precipitated withdrawal (deep link example:
https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/018932s017lbl.pdf).

Injectable naltrexone (often known by its brand name) is especially useful for individuals who prefer a once-monthly dose that eliminates the risk of skipping tablets.

What Patients Typically Experience

In the First Weeks

In clinical practice, patients often describe:

• A sense of “mental quieting” around cravings

• Reduced impulsive urges to use

• Improved confidence in their ability to stay abstinent

• Enhanced focus on therapy and recovery activities

Side effects may include mild nausea, fatigue, headache, or decreased appetite. These usually improve within 1–2 weeks.

Over Several Months

Across longer treatment timelines, individuals often report:

• Greater emotional stability

• Stronger engagement in work, family, and social life

• Reduction in relapse frequency

• Improved sleep and stress tolerance

Naltrexone is not addictive, does not cause withdrawal when stopped, and can be used long-term when clinically appropriate.

Who Should Not Use Naltrexone?

Contraindications

Naltrexone is not recommended for individuals who:

• Currently use opioids or have physical opioid dependence

• Are in acute opioid withdrawal

• Have acute hepatitis or liver failure

• Are pregnant without specialist consultation

• Are allergic to naltrexone ingredients

The NHS guidelines offer clear recommendations regarding safe prescribing, including liver assessment prior to starting therapy

Liver Function Monitoring

Although naltrexone can be used safely in many patients with mild liver enzyme elevations, clinicians typically perform:

• Baseline liver function tests

• Follow-up tests after several weeks

• Periodic monitoring during long-term therapy

As with any medication, these decisions are personalized.

Naltrexone vs. Other Treatment Options

Comparison Table

In practice, clinicians choose based on:

• Patient preference

• Medical history

• Risk of relapse

• Access to support services

Naltrexone is particularly well-suited for individuals committed to maintaining full abstinence from opioids and reducing alcohol cravings without using a medication that activates opioid receptors.

Evidence-Based Benefits

According to the WHO guidelines on the management of substance use disorders, naltrexone is considered a first-line therapy when combined with psychosocial support (deep link example:
https://www.who.int/publications/i/item/9789240005689).

Key benefits include:

• Lower relapse rates

• Reduced craving intensity

• Improved treatment retention

• Enhanced quality of life metrics

• Non-sedating and non-addictive profile

The most successful long-term outcomes occur when medication is paired with counseling, peer support, and structured recovery planning.

Frequently Asked Questions

Is naltrexone addictive?

No. It does not activate opioid receptors and carries no risk of dependence.

Can naltrexone be bought online?

Naltrexone is a prescription medication, meaning you must see a licensed healthcare provider. However, individuals often begin by exploring reputable online pharmacies. If you are evaluating safe pharmacy options, you can review trusted resources to understand how legitimate online pharmacies are vetted.

Can I drink alcohol while taking naltrexone?

Although naltrexone blocks the pleasure response, drinking while on the medication is discouraged. Most clinical programs encourage abstinence.

How long should treatment last?

Many clinicians recommend 6–12 months, though some individuals benefit from longer courses.

Practical Guidance for People Considering Naltrexone

If you’re exploring naltrexone for yourself or a loved one, consider these steps:

1. Schedule a medical evaluation.
   A clinician will assess your health history, liver function, and current substance use.

2. Create a structured recovery plan.
   Medication is most effective when combined with therapy, support groups, and lifestyle change.

3. Ask about oral vs. injectable options.
   Some people prefer daily autonomy, while others thrive with once-monthly injections.

4. Plan for the detox period if treating OUD.
   This is essential to avoid precipitated withdrawal.

5. Commit to regular follow-ups.
   Addiction treatment is collaborative. Ongoing communication with your provider strengthens results.

Case Insight: What Recovery Often Looks Like

A patient in their early 40s once told me that starting naltrexone felt like “someone turned down the noise” in their brain. This sentiment is incredibly common. Many people expect dramatic changes overnight. Instead, naltrexone often creates a steady, quiet shift—reducing cravings just enough so they can fully engage in therapy, attend meetings, and rebuild stability.

In real-world practice, the most successful patients:

• Set realistic expectations

• Use naltrexone as one part of a broader treatment plan

• Lean on support systems

• Focus on lifestyle changes, not just medication

Medication alone is rarely the full solution, but it is an extraordinarily powerful tool when used correctly.