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What are Vivitrol and Naltrexone?
Naltrexone is an opioid antagonist medication with various medical applications, including the treatment of alcohol and opioid dependence, and is generally administered orally or by injection.
Vivitrol® refers to a particular extended-release injectable preparation of naltrexone that blocks the euphoric effects of opioids for a period of approximately one month. 


How Does Naltrexone Work?
Naltrexone is a long-acting compound which binds to, and affects, the opioid receptors in the brain. These receptors are involved in many important functions such as:

  • Breathing

  • Pain perception

  • Feelings of well-being

  • Feelings of anxiety

As a powerful opioid receptor antagonist, naltrexone can be simply thought of as the “opposite” of opioid agonist drugs such as: 

  • Heroin       

  • Oxycodone        

  • Morphine        

  • Fentanyl

Naltrexone has the potential to acutely reverse the actions of opioid agonist drugs, and administering naltrexone to an opioid-dependent individual may elicit a rapid withdrawal syndrome if they have opioid agonists present in their body. 


The presence of naltrexone in the body prevents the euphoric effects of full opioid agonists. Pleasure and satisfaction from normal activities is not affected – naltrexone only inhibits the intense “high” from opioid drugs.

How is Naltrexone Used in the Treatment of Opioid Addiction?
Naltrexone is available as a once-monthly time-release injection for opioid-dependent patients who have already undergone opioid withdrawal. 

  • It is important that naltrexone therapy not begin until the individual has completely finished opioid detoxification, otherwise the patient may experience an unpleasant “precipitated withdrawal.”

  • Once detoxification is achieved, eligible patients receive an injection each month which blocks the euphoric effects of opioids. 

Unlike buprenorphine or methadone, naltrexone may not suppress drug cravings. Naltrexone helps break the cycle of addiction by preventing the reinforcing effects of euphoria, but individuals receiving naltrexone therapy may still experience a desire to use their drug of choice. Other therapies that are important components of a comprehensive treatment approach include:


Is Naltrexone Right for Me?


Since naltrexone may not eliminate cravings for opioids, naltrexone is best suited for patients who are highly motivated and who have a more stable lifestyle.

  • As with any pharmacological treatment approach, Vivitrol/naltrexone treatment should be complimented with a strong support system.

  • Active participation in one’s personal recovery program is vital in achieving long-term success.

Naltrexone is not appropriate for all patients and should only be taken under the care of a licensed physician. Some patients are better treated using buprenorphine or methadone. Please feel free to contact us at any time to discuss.

Together we can defeat opioid addiction.  Let’s start today.
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