From the Guidelines
Naltrexone is a medication used to treat opioid addiction and alcohol dependence, and it should be considered as a treatment option for patients with opioid use disorder, particularly those who are highly motivated and have a low risk of relapse 1. The typical oral dose of Naltrexone for opioid addiction is 50 mg once daily, while for alcohol dependence, it's also 50 mg once daily or 380 mg as a monthly intramuscular injection (Vivitrol) 2.
Key Considerations
- Patients must be opioid-free for 7-10 days before starting Naltrexone to prevent severe withdrawal symptoms.
- Common side effects include nausea, headache, and fatigue.
- Naltrexone works by blocking opioid receptors in the brain, reducing cravings and the rewarding effects of opioids and alcohol.
- It's most effective when combined with counseling or behavioral therapy.
- Patients should be aware that Naltrexone does not treat opioid withdrawal and may lower opioid tolerance, increasing the risk of overdose if opioid use is resumed.
- Regular liver function tests are recommended, as Naltrexone can cause liver damage in high doses.
Clinical Evidence
According to the CDC guideline for prescribing opioids for chronic pain, clinicians should offer or arrange evidence-based treatment, usually medication-assisted treatment with buprenorphine or methadone in combination with behavioral therapies, for patients with opioid use disorder 3. Naltrexone can also be used as medication-assisted treatment for opioid use disorder in nonpregnant adults, particularly for highly motivated persons 3.
Patient Education
It's crucial for patients to inform all healthcare providers about Naltrexone use, as it can interfere with pain management in emergencies. Overall, Naltrexone is a valuable treatment option for opioid addiction and alcohol dependence, and it should be considered as part of a comprehensive treatment plan that includes counseling and behavioral therapy 1.
From the FDA Drug Label
Naltrexone hydrochloride is a pure opioid antagonist. It markedly attenuates or completely blocks, reversibly, the subjective effects of intravenously administered opioids. The mechanism of action of naltrexone hydrochloride in alcoholism is not understood; however, involvement of the endogenous opioid system is suggested by preclinical data. Naltrexone hydrochloride, an opioid receptor antagonist, competitively binds to such receptors and may block the effects of endogenous opioids
The use of Naltrexone is as an opioid receptor antagonist to:
- Block the effects of opioids by competitive binding at opioid receptors
- Aid in the treatment of alcoholism by reducing alcohol consumption
- Block the physical dependence to morphine, heroin, and other opioids 4, 5, 6
From the Research
Use of Naltrexone
- Naltrexone is a broad opioid-receptor antagonist used in the management of alcohol dependence 7, 8, 9, 10.
- It is effective in reducing relapse to heavy drinking, but less effective in enhancing abstinence 7.
- Naltrexone works by blocking the pleasurable effects or "high" associated with alcohol drinking, thereby reducing alcohol craving and use 8, 9, 10.
- The therapeutic effects of naltrexone are mediated by blockade of central mu opioid receptors, particularly in the central nucleus of the amygdala, nucleus accumbens, and ventral tegmental area 10.
Administration and Efficacy
- Naltrexone can be administered orally or through injectable extended-release formulations 7, 11.
- Oral naltrexone has been shown to reduce relapse and heavy drinking in alcohol-dependent patients, but is associated with poor compliance and adverse events 11.
- Injectable extended-release naltrexone formulations have been developed to enhance treatment outcome and reduce side effects, but more studies are needed to compare their efficacy with oral naltrexone 11.
Safety and Tolerability
- The most common adverse effects reported with the use of naltrexone include nausea and vomiting 7, 8, 9.
- Naltrexone does not appear to be hepatotoxic in dosages recommended in the treatment of alcohol dependence (50 mg/day) 7, 8, 9.
- However, hepatotoxicity can occur at higher doses, and naltrexone can precipitate narcotic withdrawal in patients taking narcotics 9.