[Drug vigilance].

The goal of drug vigilance is to identify, analyse and anticipate adverse reactions resulting from the use of a drug. It is of utmost importance to ensure that a drug remains safely used, and to update its prescription when necessary. Vigilance is based on professional judgments by specialists who flag putative side effects to the network. To ascertain causality between drug use and possible side-effects, the available evidence is discussed within the vigilance network, closely involving the health professional who originally identified a possible effect, and with reference to the French drug vigilance database, as well as the existing relevant literature. The possibility of a side-effect triggers an alarm, and generates an investigation, which must often he completed by an epidemiological analysis when the risk associated with the drug is low. Drug vigilance is crucial to public health. It currently collects data both from the relevant units in pharmaceutical companies and the public drug vigilance networks.