An algorithm for the design of epidemiologic studies applied to drug surveillance

Spontaneous reporting of adverse drug reactions (ADRs), although commonly used, is of limited efficacy for the establishment of causation, and must be complemented by more rigorous epidemiologic studies. This article presents a decision algorithm that could be used as a tool in the selection of the most appropriate study design to investigate the causal relationship between a given ADR and a drug. It is based on the incidence of the ADR, on the objective of the study--determination of all the adverse effects of a given drug, or all the drugs increasing the risk of occurrence of a given adverse event--and on the funds available to the researcher.