Methadone dose and urine morphine.

When methadone maintenance was introduced in 1965, daily doses of approximately 100 mg were advocated and used; later, doses under 50 mg became common; recently, doses between 50 and 100 mg have been recommended. In a historical study and a cross-section study in one program the authors found no relationship between methadone dose and urine morphine. Patients on methadone doses under 50 mg had nearly the same percentage of urine tests positive for morphine as did those on doses of 50 mg and more. Gender, ethnic background, and age were also unrelated to urine morphine. Time on methadone was inversely related to urine morphine. Patients maintained on methadone for 3 years or longer showed a marked decrease in urine tests positive for morphine. Increased urine morphine during one decade was associated with program and community changes that could have prompted increased heroin use. These findings suggest that variables other than methadone dose affect heroin use.