naltrexone (Alkermes, 391ce2)

Extended-release naltrexone injection, 380 mg (marketed under the brand name Vivitrol) is an FDA-approved intramuscular depot formulation of naltrexone. It is formulated as microspheres using a biodegradable polylactide-co-glycolide (PLG) polymer matrix, which gradually releases naltrexone over approximately 4 weeks following a single gluteal intramuscular injection. Naltrexone is a small molecule opioid antagonist that acts as a competitive antagonist at mu-opioid receptors in the brain, blocking the euphoric and reinforcing effects of both exogenous opioids and endogenous endorphins. This formulation is indicated for the treatment of alcohol dependence in patients who can abstain from alcohol in an outpatient setting, and for the prevention of relapse to opioid dependence following opioid detoxification. By providing sustained therapeutic blood levels for a month, it addresses the compliance challenges associated with daily oral naltrexone therapy.

Brand names

VivitrolVivitrex

Other names

extended-release naltrexoneextended-release naltrexone injection, 380 mgnaltrexone for extended-release injectable suspension