Dosage regimes in the prescription of heroin and other narcotics to chronic opioid addicts in Switzerland--Swiss national cohort study.

AIMS Within the guidelines of the research programme on medical prescription of narcotics for opioid addicts (PROVE), heroin, morphine, and methadone were prescribed to heavily opioid addicted individuals in Switzerland since 1994. This contribution analyses the course of dose levels during the treatment period. DESIGN Naturalistic description of consumed dosages per day and month. SETTING AND PARTICIPANTS The study describes the dosages prescribed to all individuals who began outpatient treatment in the PROVE programme in Switzerland between 1994 and 1996. MEASUREMENTS Consumed amount of narcotics per day and the course of dosage of injectable heroin in different treatment regimes. FINDINGS Heroin was the most frequently prescribed narcotic. Of all consumption days, heroin had been applied in 77% as injection and in 9% in a smokeable form. The mean daily dosage was 474 mg for intravenous application and 993 mg for the smokeable form. Second most frequent was the prescription of oral methadone, in most cases in combination with heroin. The mean amount of daily consumption of oral methadone was 53 mg. There were dosage differences between treatment regimes. During the course of treatment the mean dosage for injectable heroin per day decreased significantly and, depending on the treatment regime, almost linearly. CONCLUSIONS The significance of heroin dosages in heroin-assisted therapy for treatment outcome should be further explored, especially in the light of the markedly higher dosages in Switzerland compared to the UK. During the treatment period, dosages did not increase but generally decreased, indicating no further increase in tolerance.