Methadone is used to treat moderate to severe pain when around-the-clock pain relief is needed for a long period of time. Methadone medicine should not be used to treat pain that you only have once in a while or as needed.
Methadone is also used together with medical supervision and counseling to treat opioid addiction (eg, heroin or other morphine-like drugs). Methadone is an opioid (narcotic) analgesic (pain medicine). It acts on the nervous system to relieve pain.