A major step towards rational use of medicines was taken in 1977, when WHO established the 1^st Model List of Essential Medicines to assist countries in formulating their own national lists. The present definition of rational use was agreed at an international conference in Kenya in 1985. In 1989, the International Network for the Rational Use of Drugs (INRUD) was formed to conduct multi-disciplinary intervention research projects to promote more rational use of medicines (email: inrud@msh.org website: http://www.msh.org/inrud). Following this, the WHO/INRUD indicators to investigate drug use in primary health care facilities were developed and many intervention studies conducted, A review of all the published intervention studies with adequate study design was presented at the 1^st International Conference for Improving the Use of Medicines (ICIUM) in Thailand in 1997. Box 3 shows a summary of the magnitude of prescribing improvement by type of intervention, The effect varied with intervention type, printed materials alone having little impact compared to the greater effects associated with supervision, audit, group process and community case management. Furthermore, the effects of training were variable and often unsustained, possibly due to differences in training quality and the presence or absence of follow-up and supervision.

BOX 3 Review of 30 studies in developing countries size of drug use improvements with different interventions