Spontaneous Reporting - United States

Spontaneous Reporting - United States

INTRODUCTION

The US Food and Drug Administration (FDA) is responsible not only for approving drugs for market-ing but also for monitoring their safety after market-ing (Ahmad, 2003; Ahmad, Goetsch and Marks, 2005). Drug approvals are based on data obtained from clinical trials that are oftentimes limited in size and duration and that have excluded patients with other therapies or comorbidities from study (Rogers, 1987). After marketing, new information relating to drug safety usually becomes available as product use becomes more widespread, and on occasion this may alter the benefit-risk profile of a drug (Friedman et al., 1999; Wysowski and Swartz, 2005).

In the United States, pharmacovigilance is regarded as those aspects of drug safety monitoring and assessment that are related to or dependent upon voluntarily reported cases of adverse drug reac-tions (ADRs) or that relate to other activities, the primary purpose of which is the generation of a signal or hypothesis of a potential adverse drug effect association. This perspective considers phar-macoepidemiology as being more closely related to population-based, systematic investigations that may range in complexity from purely descriptive to rigorous hypothesis-testing studies. There is admittedly a gray zone whereby the two approaches blend together.

There are many ways by which drug safety signals arise. The most common is through voluntary or spon-taneous case reporting to regional or national phar-macovigilance centers, such as the FDA. Case reports and case series from the literature also contribute to signal development. Other potential sources of safety concerns include pre-clinical animal testing, pre-marketing clinical trials, experience with other drugs in the same class and experience from other national centers around the world. The clinical phar-macology of the drug itself, its pharmacokinetics (absorption, distribution, metabolism and excretion) and pharmacodynamics, may raise other concerns related to organ-specific toxicity or drug–drug inter-actions.