Vivitrol (extended-release injectable naltrexone) - 2 Indications

Scroll down for more information on each indication:

• for the treatment of alcohol dependence; approved April 2006
• for the prevention of relapse to opioid dependence; approved October 2010

General Information

Vivitrol is an extended-release injectable suspension formulation of naltrexone. Naltrexone is an opioid antagonist with highest affinity for the mu opioid receptor. Naltrexone has little or no opioid agonist activity.

Vivitrol is specifically indicated for:

• the treatment of alcohol dependence in patients who are able to abstain from alcohol in an outpatient setting prior to initiation of treatment with Vitvitrol. Patients should not be actively drinking at the time of initial Vivitrol administration.
• the prevention of relapse to opioid dependence, following opioid detoxification.

Vivitrol is supplied as a liquid suspension for intramuscular injection. The recommended initial dose is 380 mg delivered intramuscularly every 4 weeks (once a month).

Mechanism of Action

Vivitrol is an extended-release injectable suspension formulation of naltrexone. Naltrexone is an opioid antagonist with highest affinity for the mu opioid receptor. Naltrexone has little or no opioid agonist activity.

Side Effects

Adverse events associated with the use of Vivitrol for alcohol dependence may include, but are not limited to, the following:

• nausea
• vomiting
• injection site reactions
• muscle cramps
• dizziness
• somnolence
• anorexia, decreased appetite or other appetite disorders

Adverse events associated with the use of Vivitrol for opioid dependence may include, but is not limited to, the following:

• hepatic enzyme abnormalities
• injection site pain
• nasopharyngitis
• insomnia
• toothache

Indication 1 - for the treatment of alcohol dependence

approved April 2006

Clinical Trial Results

The FDA approval of Vivitrol for alcohol dependence was based on a 24 week, placebo-controlled, multi-center, double-blind, randomized trial. Subjects were treated with an injection every 4 weeks of Vivitrol 190 mg, 380 mg or placebo. Subjects treated with Vivitrol 380 mg demonstrated a greater reduction in days of heavy drinking than those treated with placebo. Heavy drinking was defined as self-report of 5 or more standard drinks consumed on a given day for males and 4 or more drinks for females. Among the subset of patients (n=53, 8% of the total study population) who abstained completely from drinking during the week prior to the first dose of medication, those treated with Vivitrol 380 mg had greater reductions in the number of drinking days and the number of heavy drinking days compared with placebo-treated patients. In this subset, patients treated with Vivitrol were also more likely than placebo-treated patients to maintain complete abstinence throughout treatment. The same treatment effects were not evident among the subset of patients (n=571, 92% of the total study population) who were actively drinking at the time of treatment initiation.

Indication 2 - for the prevention of relapse to opioid dependence

approved October 2010

Clinical Trial Results

The FDA approval of Vivitrol for opioid dependence was based on a 24 week, placebo-controlled, multi-center, double-blind, randomized trial of opioid-dependent (DSM-IV) outpatients, who were completing or had recently completed detoxification. Subjects were treated with an injection every 4 weeks of Vivirol 380 mg or placebo. Oral naltrexone was not administered prior to the initial or subsequent injections of study medication. The cumulative percentage of subjects achieving each observed percentage of opioid-free weeks was greater in the Vivitrol group compared to the placebo group. Complete abstinence (opioid-free at all weekly visits) was sustained by 36% of subjects in the Vivitrol group compared with 23% of subjects in the placebo group from Week 5 to Week 24.