Naltrexone is primarily used in the treatment of alcohol and opioid dependence. It works by blocking the effects of opioids and reducing the craving for alcohol, helping individuals maintain sobriety. In the context of opioid addiction, it prevents the euphoric and sedative effects of opioids, thereby discouraging their use. For alcohol dependence, it reduces the pleasurable effects of drinking, making it easier for individuals to cut back or quit. Additionally, naltrexone is sometimes prescribed off-label for conditions like autoimmune diseases and certain types of cancer due to its immunomodulatory properties. It is also used in low doses (LDN) to manage chronic pain, fibromyalgia, and multiple sclerosis, though these applications are still under research. The medication is typically administered orally or via injection, depending on the treatment plan.