Methadone is part of a category of drugs called opioids. German doctors created it during World War II. When it came to the United States, doctors used it to treat people with extreme pain. Today, you might also get it as part of a treatment program for an addiction to heroin or narcotic painkillers. Even though it’s safer than some other narcotics, your doctor should keep a close watch while you take methadone. Taking it can lead to addiction or abuse.