Patterns of opiate use in a heroin maintenance programme.

RATIONALE

Little is known about patterns of opiate use by heroin addicts.

OBJECTIVES

To describe opiate use over time among heroin addicts who had access to legally prescribed intravenous heroin and oral opiates.

METHODS

Analysis of daily drug administration records of 37 patients enrolled in the Geneva heroin maintenance programme for 4-29 months (total 23,136 patient-days).

RESULTS

The average dose of intravenous heroin was 466 mg/day; the total opiate dose, after conversion of oral opiates to heroin-equivalents, was 543 mg/day. Patients received intravenous heroin only on 39% of days, oral opiates only on 7% of days, and mixed regimens on 49% of days; the remaining 4% of days were spent outside the programme, usually on oral opiates. The daily dose of heroin-equivalents increased during the first trimester in the programme, by 30 mg/day per month (95% confidence interval 12-46 mg/day per month), but decreased gradually thereafter, by 12 mg/day per month (95% confidence interval, 8-17 mg/day per month). In patients who alternated between heroin and methadone, 1 mg methadone typically replaced 4.1 mg heroin. During follow-up, five patients switched to methadone maintenance, five underwent detoxification, and three were discharged for noncompliance with regulations.

CONCLUSIONS

Heroin users who have facilitated access to legally prescribed drugs consume about 0.5 g heroin per day. Consumption patterns vary, but the daily amount of opiates remains stable or decreases over time. A substantial minority of patients elect for alternative treatments after several months of heroin maintenance.