Test Details: Methadone has similar pharmacological properties as Morphine and is equipotent as an analgesic when administered parenterally. Unlike Morphine it produces marked sedative effects with repeated administration due to drug accumulation. It has been used as a major substitute for Heroin, Morphine & Codeine in drug maintenance treatment clinics. The duration of drug effect is 12-24 hrs and about 5-50% is excreted unchanged in the urine. The drug can be detected in urine up to 24 hrs after the overdose.