Acetylmethadol versus methadone: Human mood and motility

Outpatients receiving daily methadone-maintenance treatment were crossed over to alternating-day doses of l-alpha-acetylmethadol, receiving placebo on between-dose days. Spontaneous motility was dramatically higher on acetylmethadol dose days than on placebo days; activity on methadone days was intermediate between these extremes. Patients reported less vigor, more fatigue, and fewer ejaculations on placebo days than on acetylmethadol days, and patients' mood while on this drug was slightly euphoric in comparison to methadone. These effects are subtle, but such drug-induced variations in day-to-day behavior might adversely affect social interactions.