The Swiss heroin trials: testing alternative approaches

Prescribed heroin is likely to have a limited role

Over half a million heroin misusers receive oral methadone maintenance treatment world-wide1 but the maintenance prescription of injectable opioid drugs, like heroin, remains controversial. In 1992 Switzerland began a large scale evaluation of heroin and other injectable opiate prescribing that eventually involved 1035 misusers. 2 3 The results of the evaluation have recently been reported.4 These show that it was feasible to provide heroin by intravenous injection at a clinic, up to three times a day, for seven days a week. This was done while maintaining good drug control, good order, client safety, and staff morale. Patients were stabilised on 500 to 600 mg heroin daily without evidence of increasing tolerance. Retention in treatment was 89% at six months and 69% at 18 months.4

The self reported use of non-prescribed heroin fell signifianctly, but other drug use was minimally affected. The death rate was 1% per year, and there were no deaths from overdose among participants while they were receiving treatment. There were limited reports of problems in the local neighbourhood, despite the high frequency of daily attendance. Heroin diversion was not a major problem, although some trial participants were expelled for attempting to remove heroin from the clinic or to smuggle cocaine into the clinic.4

The Swiss trials have encouraged proposals for similar trials in other countries, including Australia,5 and, more recently, Denmark, Luxemburg, and the Netherlands. Any country that contemplates a trial of heroin prescription will need to address several problems that arose in the Swiss trials. Firstly, the participants' preference for heroin over any alternative opioid undermined the randomised controlled design that was originally planned and resulted finally in a descriptive outcome study. Secondly, in the Swiss trials heroin was prescribed as part of a comprehensive social and psychological intervention. In the absence of any comparison treatment it was impossible to disentangle the pharmacological effects of heroin from the effects of providing treatment in well resourced clinics with highly motivated staff. An assessment of this issue requires an appropriate comparison treatment. Thirdly, the unique social and political context of the Swiss trials makes it uncertain how to generalise their findings to other countries. Switzerland is a wealthy society that has a comprehensive healthcare system that includes a well developed drug treatment system whose staff have substantial experience with opioid substitution treatment. Even so, heroin prescription in Switzerland has been an addition to existing treatment approaches: it has not replaced the methadone maintenance still prescribed for 15 000 Swiss heroin misusers but has been an expensive option for a minority of severely dependent misusers who have not responded to existing treatments.

Given this limited role, the controversy surrounding heroin prescription in Switzerland and elsewhere has been out of all proportion to its likely role as a treatment option. A recent debate about heroin prescription in Australia, for example, dominated public discussion of drug policy for nearly a month before the government decided against proceeding with the trial. The debate also had other untoward effects: supporters of the trial argued that something radical was needed, thereby encouraging the view that Australia was in the midst of a national heroin crisis. Their opponents agreed but countered that this was evidence that the national policy of harm minimisation, which sanctions methadone maintenance and needle and syringe exchange, had failed.

These issues have not been resolved by the Swiss trial. There are clearly still questions that remain unanswered. The most important is what is the comparative usefulness and cost effectiveness of injectable heroin and oral methadone maintenance? A convincing answer to this question would substantially improve our understanding of the role of this controversial treatment.