New horizons in post-marketing surveillance.

Post-marketing surveillance is the process of monitoring and evaluating the safety of marketed medicines using a variety of methods. However, many doctors believe that post-marketing surveillance has a more limited meaning, ie an observational study of a new medicine sponsored by a pharmaceutical company. Although such studies were performed extensively in the United Kingdom during the 1980s, few have been published. Their purpose was to study large populations of users in ordinary practice with the aim of identifying hazards that had been missed, because clinical trials were too small, too short or did not always reflect real life. To some extent these studies have now fallen into disrepute, both on scientific grounds and because they have often been thought to be a thinly-disguised promotional exercise. The purpose of this article is to examine some of the previous problems with post-marketing surveillance and to propose new directions for the future.