Methadone for chronic non-cancer pain in adults.

Methadone belongs to a class of analgesics known as opioids, that are considered the cornerstone of therapy for moderate-to-severe pain due to life-threatening illnesses; however, their use in chronic non-cancer pain (CNCP) is controversial. Methadone has many characteristics that differentiate it from other opioids, which suggests that it may have a different efficacy and safety profile.