Once-A-Month Naltrexone Injection for Substance Use Disorders

Naltrexone is a once-a-month injectable medication used in conjunction with other therapies to treat alcohol and opioid use disorders. It is considered one of the most effective pharmaceutical treatments for alcohol use disorder.

How Does Naltrexone Work? Naltrexone's mechanism of action involves reducing the brain's response to alcohol and opioids, potentially leading to decreased cravings and use of these substances.

At a Glance: - Naltrexone is administered as a monthly injection known as Vivitrol. - It helps individuals struggling with alcohol and opioid addiction maintain sobriety. - Research suggests that it can reduce drinking by 17% to 25%, and over 90% of opioid users achieved drug-free status during treatment.

Conditions Naltrexone Treats: Naltrexone is prescribed for various purposes, including:

• Alcohol Dependence: As one of the three approved medications for treating alcohol dependence, naltrexone aids individuals in avoiding relapse after quitting alcohol consumption.
• Opioid Dependence: Naltrexone is effective in treating people addicted to prescription opioids and heroin. It is also being studied for cocaine use disorders. Naltrexone targets the brain's response to opioids, blocking their effects.
• Off-Label Uses: Naltrexone has off-label uses in managing pain associated with conditions like fibromyalgia and chronic fatigue syndrome.

Benefits of Monthly Injection vs. Daily Pill: Naltrexone is available as both a daily pill and a monthly injection, with the latter offering significant advantages.

• Daily Naltrexone Pill: Traditionally, naltrexone was administered as a daily pill, commonly known as ReVia or Depade. This form remains widely used, but individuals struggling with alcohol use disorder may face challenges maintaining compliance with daily dosage regimens.

• Monthly Naltrexone Injection: In 2006, the FDA approved the once-a-month naltrexone injection, branded as Vivitrol, for treating alcohol dependence. This extended-release formula gradually delivers naltrexone over a month. In 2010, Vivitrol was also approved for treating opioid dependence.

Research indicates the effectiveness of monthly naltrexone injections in reducing alcohol consumption. The extended-release formulation makes it preferable for opioid use disorder, as it improves medication compliance and leads to better outcomes.

Before Starting Naltrexone: Prior to initiating naltrexone injection therapy, your healthcare provider will perform a physical examination, evaluate liver function, and conduct a drug test. As an opioid antagonist, naltrexone can trigger opioid withdrawal if taken within 10 days of opioid use.

Sustained opioid abstinence is crucial before starting naltrexone injections.

Precautions and Contraindications: - Active Opioid Use: Monthly naltrexone injections and other naltrexone-containing medications are contraindicated for individuals actively using opioids. Discontinuing naltrexone can reduce opioid tolerance, potentially leading to accidental overdose and death if opioid use is resumed at previous levels. - Liver Toxicity: The injectable form may mitigate the risk of liver toxicity compared to oral naltrexone, which undergoes first-pass metabolism in the liver. However, the FDA cautions against exceeding the recommended naltrexone dosage, as it can still cause liver toxicity. People with acute hepatitis or liver failure should avoid monthly naltrexone injections.

How to Take Naltrexone: If you suspect you have an alcohol or opioid use disorder or want to reduce your substance use, consult your doctor. They will evaluate your health and determine if monthly naltrexone injections are appropriate.

If deemed suitable, your doctor will administer an intramuscular injection in the gluteal muscles every four weeks. The extended dosing interval, requiring only one injection per month, can enhance medication adherence compared to daily pills.

Naltrexone Side Effects: The side effects of monthly naltrexone injections are similar to those of daily oral naltrexone, including:

• Abdominal pain
• Back pain
• Decreased appetite
• Dizziness
• Fatigue
• Headache
• Injection site reactions
• Joint pain
• Muscle aches
• Vomiting

A large study on naltrexone's effectiveness in treating alcohol use disorder revealed that 14.1% of individuals taking a 380 mg dose discontinued treatment due to side effects like nausea, headache, and fatigue, while only 6.7% in the 190 mg group discontinued treatment due to adverse effects.

Severe Side Effects: In some cases, severe side effects may occur:

• Allergic reactions
• Depressive symptoms
• Liver damage
• Severe injection site reactions requiring intervention
• Suicidal thoughts or behaviors

If you experience signs of a severe allergic reaction, such as trouble breathing, difficulty swallowing, or swelling of your mouth, face, or hands, seek immediate medical attention.

If you have suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

Effectiveness of Naltrexone: Research indicates the effectiveness of naltrexone in treating alcohol and opioid use disorders.

• Alcohol Use Disorder: Studies have shown that injecting 380 mg of naltrexone resulted in a 25% reduction in heavy drinking days, while a 190 mg dose reduced heavy drinking days by 17%. Men may respond better to naltrexone treatment than women, and individuals who start treatment after a period of abstinence may experience enhanced effects.

• Opioid Use Disorder: A study examining the effectiveness of monthly naltrexone for opioid use disorder revealed significant improvement in opioid abstinence. Participants receiving monthly naltrexone injections achieved abstinence in approximately 90% of the study weeks, compared to 35% abstinence in the placebo group.

Conclusion: If you or a loved one struggles with alcohol or opioid use disorder, naltrexone is a treatment option worth considering. Monthly injections can effectively reduce alcohol or drug use. The injectable form improves treatment adherence, leading to better recovery outcomes and chances of success. Consult your doctor about your treatment options if you think naltrexone might be suitable for you.