Is methadone considered an extended release opioid?
Methadone is not considered an extended release opioid; however, its long serum half-life can sometimes lend it to being labeled that way. Methadone has a very long and variable serum half-life (24 to 36 hours, outliers as long as 60 to 150 hours). Methadone’s onset of action is 30 minutes to 2 hours, and due to the long serum half-life, methadone can build up slowly in a patient’s tissue. Methadone’s unique pharmacokinetic and pharmacodynamic properties typically require multiple daily doses (usually 3 to 4 doses per day). Although the analgesic onset is similar to most opioids, the duration of analgesia is not (e.g., 6 to 12 hours).