Methadone, sold under the brand name Dolophine among others, is an opioid used to treat pain and as maintenance therapy or to help with detoxification in people with opioid dependence. Detoxification can either occur relatively rapidly in less than a month or gradually over as long as six months. While a single dose has a rapid effect, maximum effect can take five days of use. The effects last about six hours after a single dose and a day and a half after long-term use. Methadone is taken by mouth or by injection into a muscle or vein.