Drug utilization study methodologies: national and international perspectives.

This paper in the series on pharmacoepidemiology describes the history, development, and present status of drug utilization activities. The various methodologies employed in drug utilization studies are evaluated and presented along with a listing of the principal drug databases available for drug utilization research. An analysis is presented comparing the validity of drug consumption rates based on individual patient usage or drug cost data as adopted in North America and the defined daily dose unit as developed in Europe. Drug utilization derives its importance in pharmacoepidemiology from the fact that it provides the methodological rigor for defining the denominator data needed in pharmacoepidemiological research.