<P> Postmarketing surveillance (PMS) (also post market surveillance) is the practice of monitoring the safety of a pharmaceutical drug or medical device after it has been released on the market and is an important part of the science of pharmacovigilance . Since drugs and medical devices are approved on the basis of clinical trials, which involve relatively small numbers of people who have been selected for this purpose--meaning that they normally do not have other medical conditions which may exist in the general population--postmarketing surveillance can further refine, or confirm or deny, the safety of a drug or device after it is used in the general population by large numbers of people who have a wide variety of medical conditions . </P> <P> Postmarketing surveillance uses a number of approaches to monitor drug and device safety, including spontaneous reporting databases, prescription event monitoring, electronic health records, patient registries, and record linkage between health databases . These data are reviewed to highlight potential safety concerns in a process known as data mining . </P> <P> Health Canada is the regulatory body which approves drugs, and it has a division called "Marketed Health Products Directorate" (MHPD) which coordinates Canadian postmarketing surveillance . </P>

Methods of post marketing surveillance in clinical research