Elevated Liver Enzymes with Naltrexone Might Not Indicate Toxicity

The mu-opioid receptor antagonist naltrexone, which is approved for the treatment of alcohol and opiate dependence, has a black-box warning for dose-related hepatotoxicity based on reports of asymptomatic aminotransferase elevations. Although this does not occur at usual doses, concerns have been raised that naltrexone might be risky for patients with preexisting liver disease. Researchers examined naltrexone-associated changes in liver enzymes in a study that randomized 250 opiate-dependent patients (mean age, 30; history of hepatitis C virus [HCV] infection, 89% of patients; positive HIV test, 42%) to 6 months of injectable long-acting naltrexone or placebo. The multicenter Russian study was sponsored by the manufacturer and reported by t…