Naltrexone 50 mg: Uses, Benefits, Dosage, Side Effects & Safety Guide

💊 What is Naltrexone 50 mg?

Naltrexone 50 mg is a prescription medication primarily used to treat opioid and alcohol dependence. It belongs to a class of drugs known as opioid antagonists, which work by blocking the effects of opioids in the brain. Unlike Low Dose Naltrexone (LDN), which is used off-label in much smaller doses, Naltrexone 50 mg is the standard therapeutic dose approved by the FDA for addiction treatment.

• Brand names: ReVia, Vivitrol (injectable form)
• Form: Oral tablet (50 mg) or extended-release injection (Vivitrol)
• Approval: FDA-approved for alcohol and opioid use disorder

🔬 How Naltrexone 50 mg Works

Naltrexone binds to mu-opioid receptors in the brain and blocks the euphoric and sedative effects of drugs like heroin, morphine, and codeine. This makes opioid use less rewarding and reduces cravings. For alcohol dependence, it reduces the urge to drink by modulating dopaminergic pathways involved in addiction and reward.

🩺 Uses of Naltrexone 50 mg

✅ FDA-Approved Indications:

1. Opioid Use Disorder (OUD)
   • Prevents relapse after detoxification
   • Must be opioid-free for 7–14 days before starting
2. Alcohol Use Disorder (AUD)
   • Reduces craving and risk of heavy drinking
   • Effective with psychosocial support (e.g., counseling)

⚠️ Off-Label Uses (Less common):

• Impulse control disorders (e.g., gambling)
• Eating disorders (binge eating, bulimia)
• Self-injurious behavior
• Borderline personality disorder (BPD)

📋 Dosage and Administration

Oral Tablets:

• Typical dose: 50 mg once daily
• Alternative: 100 mg every other day or 150 mg every 3rd day (for adherence)

Injectable (Vivitrol):

• Dose: 380 mg intramuscular injection once every 4 weeks
• Used when daily adherence is a concern

💡 Patients must be completely opioid-free before starting to avoid precipitated withdrawal.

✅ Benefits of Naltrexone 50 mg

• Prevents opioid relapse by blocking euphoric effects
• Reduces alcohol cravings and relapse risk
• Non-addictive and no potential for abuse
• No sedation, unlike methadone or buprenorphine
• Improves long-term recovery outcomes when combined with therapy

⚠️ Side Effects of Naltrexone 50 mg

Most side effects are mild and temporary. Serious side effects are rare but possible.

Common:

• Nausea or vomiting
• Headache
• Dizziness
• Fatigue
• Anxiety
• Sleep disturbances
• Muscle or joint pain

Serious:

• Liver toxicity (especially with high doses)
• Depression or suicidal thoughts (rare but reported)
• Allergic reaction or injection site reaction (with Vivitrol)

📌 Routine liver function tests are recommended before and during treatment.

🚫 Contraindications and Warnings

• Current opioid use or dependence (must be detoxed)
• Acute hepatitis or liver failure
• Allergy to naltrexone or components
• Pregnancy or breastfeeding (use only if benefits outweigh risks)

💊 Drug Interactions

• Opioids: Should not be used concurrently
• Opioid-containing medications (cough meds, painkillers) must be avoided
• Hepatotoxic drugs: Use with caution (may increase liver burden)

🔐 Precautions

• Inform healthcare provider of all medications, drug history, and liver issues
• Carry a medical alert card indicating naltrexone use in case of emergency
• Be aware that larger opioid doses will be needed to overcome blockade—this can be dangerous if naltrexone is stopped and opioids are resumed

🧪 Clinical Evidence and Effectiveness

• Studies show significant reduction in relapse rates among individuals taking naltrexone vs. placebo
• Works best when combined with behavioral therapy, peer support, and counseling
• Effective as a long-term maintenance treatment for sustaining abstinence