Naltrexone Side Effects: What to Know for a Safe Recovery Journey

Starting medication-assisted treatment can be a powerful step towards recovery, but it's natural to have concerns about how it may affect you. Naltrexone’s side effects vary from person to person, and understanding them can help you feel more prepared. 

Understanding what Naltrexone is, how it works, and what side effects to watch for can help you feel more in control of your treatment process. While many people tolerate it well, some may experience nausea, fatigue, headaches, or mood shifts. Serious side effects are uncommon, but it’s important to know when to seek medical advice.

This guide is here to walk you through common Naltrexone side effects, how to manage discomfort, and what to expect — so you can stay focused on your recovery with confidence and clarity.

Before exploring Naltrexone side effects, it is imperative to understand the medication itself. Naltrexone is a medication used to support individuals recovering from substance use disorders, specifically alcohol and opioid dependence. It is classified as an opioid antagonist, meaning it works by blocking opioid receptors in the brain. 

Unlike opioid medications that activate these receptors to produce pain relief or euphoria, Naltrexone prevents opioids from having any effect and helps reduce cravings.

Approved Uses of Naltrexone

Naltrexone is FDA-approved for the treatment of:

• Alcohol Use Disorder (AUD) – Helps individuals reduce alcohol consumption by diminishing cravings and blocking the pleasurable effects of drinking.

• Opioid Use Disorder (OUD) – Prevents opioids from producing a high, making relapse less likely. It is typically prescribed after detoxification, as taking Naltrexone while opioids are in the system can trigger withdrawal symptoms.

How Naltrexone Works

Naltrexone binds to opioid receptors in the brain without activating them. This process:

• It prevents opioids from binding and causing euphoria or sedation.

• Reduces cravings for opioids and alcohol over time.

• It helps prevent relapse by making substance use less rewarding.

Like any medication, Naltrexone may cause side effects. While most are mild and improve over time, it’s essential to be aware of potential reactions. Side effects can vary depending on individual factors such as overall health, dosage, and how the body responds to the medication.

Gastrointestinal Issues

Naltrexone can affect the digestive system, leading to:

• Nausea – One of the most frequently reported side effects, often mild and temporary. Taking Naltrexone with food may help reduce discomfort.

• Vomiting – Less common but can occur, especially in the early stages of treatment.

• Diarrhea – Some individuals experience loose stools, which usually resolve as the body adjusts.

• Abdominal Pain – Cramping or discomfort may occur, but staying hydrated and eating balanced meals can help manage symptoms.

Central Nervous System Effects

Some individuals may experience neurological side effects, including:

• Headaches – A common complaint that often diminishes over time. Staying hydrated and getting adequate rest may help.

• Dizziness – This may occur, particularly when standing up quickly. Moving slowly from a seated or lying position can help prevent lightheadedness.

• Insomnia – Some people have trouble falling or staying asleep, especially when first starting Naltrexone. Establishing a bedtime routine and limiting caffeine intake can be beneficial.

• Anxiety – While Naltrexone can help with cravings, some individuals may feel increased nervousness or restlessness. Relaxation techniques, such as deep breathing or mindfulness, may help.

Other Common Side Effects

• Fatigue – Some people experience tiredness or low energy levels, which typically improve as the body adjusts to the medication.

• Joint or Muscle Pain – Mild aches may occur, but regular movement and gentle stretching can help alleviate discomfort.

• Decreased Appetite – Naltrexone may suppress appetite in some individuals, leading to reduced food intake. Ensuring proper nutrition is essential for maintaining overall well-being.

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While Naltrexone is generally well-tolerated, some individuals may experience severe side effects. Although these are rare, recognizing the signs early can help prevent complications.

Hepatotoxicity (Liver Damage)

The liver processes Naltrexone, and in rare cases, it can cause liver toxicity, especially at high doses. People with pre-existing liver conditions should use caution when taking this medication.

Signs of potential liver damage include:

• Yellowing of the skin or eyes (jaundice)

• Dark-colored urine

• Persistent nausea or vomiting

• Loss of appetite

• Upper right abdominal pain

If any of these symptoms occur, medical attention should be sought immediately. To minimize risks, healthcare providers often perform liver function tests before starting Naltrexone and periodically during treatment.

Precipitated Withdrawal

Naltrexone is an opioid antagonist, meaning it blocks opioid receptors. If taken too soon after opioid use, it can trigger precipitated withdrawal, a sudden and intense withdrawal reaction.

Symptoms of precipitated withdrawal include:

• Severe nausea and vomiting

• Intense sweating

• Muscle aches and cramping

• Anxiety and restlessness

To prevent this, individuals must be completely detoxed from opioids before starting Naltrexone—typically at least 7–10 days after the last opioid use. Healthcare providers will assess readiness before prescribing the medication.

Allergic Reactions

Although rare, some people may experience an allergic reaction to Naltrexone. Signs of a severe allergic response (anaphylaxis) include:

• Skin rash or hives

• Swelling of the face, lips, or throat

• Difficulty breathing or wheezing

While many Naltrexone side effects are mild and temporary, proper management can help improve comfort and ensure a smoother recovery process. 

By staying informed, communicating with healthcare providers, and making lifestyle adjustments, individuals can minimize discomfort and remain committed to their treatment.

Monitoring and Communication

Regular medical check-ups are essential while taking Naltrexone. Healthcare providers can:

• Assess how the body is responding to the medication.

• Monitor liver function to ensure safety.

• Guide managing any side effects.

Open communication is key. If side effects persist or become difficult to handle, discussing concerns with a doctor can help adjust the treatment plan or explore alternative solutions.

Lifestyle and Support Strategies

Dietary Adjustments for Gastrointestinal Issues

• Eat small, frequent meals to reduce nausea.

• Stay hydrated to prevent dehydration from vomiting or diarrhea.

• Avoid spicy, greasy, or overly rich foods that may upset the stomach.

Stress Management for Anxiety and Insomnia

• Practice deep breathing exercises or meditation to ease nervousness.

• Establish a consistent sleep routine by going to bed simultaneously each night.

• Limit caffeine, alcohol, and screen time before bedtime to improve sleep quality.

Physical Activity for Fatigue and Muscle Pain

• Engage in light exercise, such as walking or stretching, to boost energy.

• Incorporate low-impact activities like yoga to reduce muscle tension.

• Stay hydrated and maintain good posture to prevent unnecessary strain.

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Naltrexone is a valuable tool in addiction recovery, but certain factors may affect how it works for each individual. Before starting treatment, pregnancy, medication interactions, and personal health conditions should all be considered.

Pregnancy and Breastfeeding

There is limited data on Naltrexone’s safety during pregnancy and breastfeeding. While it may be safer than opioid-based treatments, risks and benefits should be discussed with a healthcare provider.

Drug Interactions

Naltrexone may interact with:

• Opioid medications (pain relievers, cough syrups, anesthesia) – blocked effects.

• Psychiatric medications – possible dosage adjustments needed.

• Over-the-counter drugs, supplements, and alcohol – potential interactions.

Always inform your doctor of all medicines before starting Naltrexone.

Individual Variations

Response to Naltrexone may vary based on:

• Age and gender – potential differences in metabolism and side effects.

• Overall health – liver/kidney conditions may require monitoring.

• Mental health – possible mood changes in individuals with anxiety or depression.

Naltrexone is a powerful tool in recovery, but like any medication, it comes with potential side effects. While most are mild and temporary, understanding Naltrexone side effects helps you stay informed and prepared. 

If you have concerns or need support in your recovery journey, The Edge Treatment Center is here to help. Our compassionate team provides personalized treatment plans to guide you toward a healthier, addiction-free life. Don’t let uncertainty hold you back—reach out today and take the next step toward lasting recovery.

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If you or a loved one is struggling with addiction, there is hope. Our team can guide you on your journey to recovery. Call us today.

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