Methadone is an opioid analgesic that is used to treat severe pain and prevent withdrawal symptoms in opioid addicts. It works by binding to the same receptors in the brain as opioids like heroin and preventing cravings. While methadone is itself addictive, it blocks the euphoric effects of other opioids when taken as prescribed, allowing addicts to break the cycle of addiction and seek further treatment without withdrawal symptoms. There is an ongoing debate around replacing one addiction for another with methadone maintenance treatment, but proponents argue it provides a medically-supervised and safer alternative while the person seeks additional help for their underlying addiction.