Methadone Methadone is a synthetic opioid used medically as an analgesic, antitussive and as a maintenance anti-addictive for use in patients on opioids. The drug was developed in 1937 in Nazi Germany and although chemically unlike morphine or heroin, methadone also acts on the opioid receptors and thus produces similar effects. The drug was given the trade name "dolophine" from the Latin dolor meaning pain The effects created by the use of methadone include drowsiness, sedation, dizziness, lightheadedness, mood swings (euphoria to dysphoria), depressed reflexes, altered sensory perception, stupor, and coma. The drug manufacturer cautions that methadone may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, and that the sedative effects of the drug may be enhanced by concurrent use of other CNS depressants, including alcohol. In the DUI context and field sobriety testing, horizontal gaze nystagmus, vertical gaze nystagmus, and lack of convergence are not present. Pupil size is constricted and there is little to no reaction to light. Pulse rate, blood pressure, and body temperature are lower.