Vivitrol (naltrexone) can help reduce opioid or alcohol cravings in people with an opioid or alcohol use disorder. It blocks the euphoric effects of opioids or alcohol, reduces cravings and helps to prevent relapse. It is administered as a once-monthly injection.

Research suggests that Vivitrol leads to a reduction in cravings within the first two to three weeks of treatment and continues to stave off cravings throughout treatment.

• One clinical trial found that Vivitrol seemed to reduce self-reported opioid cravings more quickly than Suboxone (buprenorphine and naloxone), another drug used to prevent opioid relapse. However, after 24 weeks of treatment, both drugs were associated with similar levels of self-reported opioid cravings.
• In another trial comparing Vivitrol and Suboxone, prior heroin users receiving Vivitrol had fewer heroin cravings and thoughts of heroin than those who took Suboxone.
• A study of people being treated for alcohol dependence in an inpatient substance abuse program found that those who received Vivitrol saw their alcohol cravings dissipate more quickly than those who did not take Vivitrol.

However, some patients may experience cravings during treatment. If breakthrough cravings occur, a doctor may recommend getting Vivitrol injections once every three weeks instead of the standard four-week cycle. Cravings are more likely to return after discontinuing treatment with Vivitrol.

How Vivitrol curbs cravings is not fully understood. One potential explanation is that people are less likely to crave opioids or alcohol if they know that they will not feel their euphoric effects while taking Vivitrol.