Differentiation in the Amsterdam methadone dispensing circuit: determinants of methadone dosage and site of methadone prescription

Aims. To evaluate the Methadone Dispensing Circuit in Amsterdam by identifying determinants of methadone dosage and client characteristics in the different types of methadone programmes. Design and participants. Four hundred and forty-four participants of a cohort study of drug users in Amsterdam who had consented to link data of the Central Methadone Register to the cohort data. Findings. From 1985 to 1994, methadone dosage increased from 41 to 59 mg/day. The mean methadone dosage was higher for ethnic West Europeans, Germans, older drug users, HIV-positive drug users, those with a longer duration of prostitution, current injectors, those with a longer duration of injecting, longer duration of methadone use, higher frequency of being dispensed methadone and clients of the prostitutes' and foreigners' outpatient clinic. For clients of the general practitioner, at the police station and in prison the methadone dosage was lower. We found different sets of client characteristics in those receiving methadone at the methadone outpost, the methadone bus, the prostitutes' and foreigners' outpatient clinic, the general practitioner and the outdoor addiction clinic. Conclusions. These results indicate that the Amsterdam system is highly differentiated in a way that is largely concordant with the intended general policy on methadone treatment.