Prescribing errors cause substantial potentially avoidable patient harm. There is increasing evidence that the implementation of clinical decision support systems to support prescribing may reduce the risk of such errors. Efforts have thus far concentrated on the implementation of these systems within local health communities. However, considerable potential benefit exists in sharing the content of these prescribing decision support systems across geographical boundaries, including the sharing of experiences and expertise and cost reduction, which could in turn potentially increase accessibility to low resource settings. Technical, commercial and regulatory issues would however first need to be overcome in order to facilitate such a development. In this paper, the authors reflect on some of the opportunities and challenges inherent in trying to develop an internationally agreed and shared computerised decision support system aiming to enhance prescribing safety.