Introduction

Although some will question the use of the term experiment on formal grounds, most experts will likely agree that the widespread marketing of a new drug is in fact a large experiment on a population. This is especially the case when it concerns a novel molecular entity with potentially a new set of clinical experiences. As the marketing of new drugs includes the discovery of adverse effects, the public's health would be best protected by a complementary set of techniques for the detection, verification, and quantification of safety issues. Yet the current approach to this is scattered and disappointing. We discuss why healthcare professionals are not aware of all safety problems of a drug at its introduction and why pharmacoepidemiology should complement the indispensable observational method of case reporting.

Sources and selection criteria

Our review is based on a search of PubMed using the terms adverse effect, adverse reaction, ADR, adverse event, adverse reaction monitoring, pharmacovigilance, cohort study, and case-control study. This yielded several thousand papers from which we excluded individual case reports and case series. From a list of cohort and case-control studies, we picked some recent examples of pharmacoepidemiological studies of adverse events with databases. We used the references from 50 of the most recent reviews, to gather the most important papers on this subject.

Credit: SUE SHARPLES

Limitations of clinical trials

Before drugs are marketed, they are extensively tested in animals and in clinical trials in humans. These tests tell much about the drug's efficacy but for several reasons relatively little about safety (box).

Good economical reasons preclude an endless quest for research before drugs are registered. Such …