What are the side effects of naltrexone?
In the largest study, the most common side effect of naltrexone affected only a small minority of people and included the following: nausea (10%), headache (7%), dizziness (4%), fatigue (4%), insomnia (3%), anxiety (2%), and sleepiness (2%). These side effects were usually mild and of short duration. As treatment for alcoholism, naltrexone side effects, predominantly nausea, have been se vere enough to discontinue the medication in 5-10% of the patients starting it. For most other patients side effects are mild or of brief duration. One serious possibility is that naltrexone can have toxic effects on the liver. Blood tests of liver function are performed prior to the onset of treatment and periodically during treatment to determine whether naltrexone should be started and whether it should be discontinued if the relatively rare side effect of liver toxicity is taking place.
