ABSTRACT
Pharmacovigilance involves the detection of unexpected, and often undesirable, adverse effects of drugs. Pharmacoepidemiology, often considered a sub-domain in pharmacovigilance, attempts to quantify the frequency of these adverse effects, and to identify sub-populations for which there are variations in the magnitude of effects. Until recently, adverse drug effects were of limited concern as it was difficult enough to treat the disease. Reports of adverse drug effects began at the end of the nineteenth century when it was found that the use of chloroform led to an increased risk of cardiac arrest. Table 22.1 lists examples of serious and unexpected adverse effects of drugs that have subsequently been discovered (Meyboom 1998).
