There has been increasing interest in recent years in understanding the mechanisms and processes at work when people change the way they take their drugs.

Assessing and understanding these ‘route transitions’ and developing appropriate and effective interventions that promote safer drug use is likely to be an important area of harm reduction in the future.

The materials here have been written to give policy makers, funding organisations, drug service providers and drug users an introduction to the ‘route transitions’ literature, the ‘route transition interventions’ (RTIs) that have been developed; the framework we developed with Population Services International for conducting formative research to understand local patterns of drug transitions; and some guidance on how to produce effective and appropriate interventions to promote healthy route transitions.