The pharmaceutical grade heroin hydrochloride and heroin base for the study was supplied by a pharmaceutical company and delivered to a central pharmacist. In the case of heroin hydrochloride, the central pharmacist further prepared the heroin by diluting the heroin in water, dividing the solution over separate multidose vials, and subsequently freeze-drying the solution. The vials containing heroin powder were then transported to the treatment sites for further preparation for individual patients. Heroin base was prepared by the central pharmacist by mixing the heroin base with caffeine in a ratio of 3 : 1, and filling the mixture into capsules or sachets, which were then transported to the treatment sites. All procedures in the central pharmacy were conducted in accordance with the guidelines for Good Manufacturing Practice (ICH, 2000).
The central pharmacist was responsible for the drug accountability until the moment of delivery at the local treatment site. The responsibility for the drug accountability was then taken over by the treatment site, which was assisted by a local pharmacist with regard to the documentation of the medication supplies and the dispensing - and if necessary destruction - of the medication. Lastly, the treating physician was responsible for the administration of the medication to the individual patients. The actual amount and route of the medication, as well as any deviation from the prescription regime, were documented in detail on an individual basis for all patients on separate drug accountability forms, and closely monitored by the independent monitoring organization.