The fixed combination of extended-release naltrexone and bupropion has been developed as a weight loss agent and was approved for use in the United States in 2014. This combination has not been linked to serum enzyme elevations or clinically apparent liver injury, but has had limited general use. Bupropion, approved for depression and as an aid for smoking cessation, has been implicated in rare instances of acute liver injury. Naltrexone, an opioid receptor antagonist, is used for opioid and alcohol dependency and has been shown to cause serum aminotransferase elevations when given in high doses but has not been shown to cause clinically apparent liver injury.