Research methods in drug surveillance

Adverse drug reactions must be monitored, beginning with the development of a new drug, and continuing throughout its complete life cycle. During these various stages, different methods are necessary. This paper describes the advantages and disadvantages of common methods of collecting data on adverse drug reactions after a drug has been approved. We then concentrate on two drug surveillance projects, the Prescription Event Monitoring (PEM) of the Drug Surveillance Research Unit and the AMSP Project ("Arzneimittelsicherheit in der Psychiatrie", Drug Safety in Psychiatry). AMSP is compared to cohort studies and spontaneous reporting systems on the one hand, and the specialised PEM project, on the other. The possible influence of various sources of bias is critically analysed.