Methadone is in a class of medications called opiate analgesics. Methadone works to treat pain by changing the way the brain and nervous system respond to pain. Methadone can work as a substitute for opiates by producing effects similar to those that opiates produce. Methadone prevents withdrawal symptoms in people who have them as the result of discontinuing opiate use. Methadone comes as a tablet, a dispersible tablet (can be dissolved in liquid), a solution (liquid), and a concentrated solution (a liquid that must be diluted before use) to take by mouth.