[What phase IV should be like for an anxiolytic agent].

The phase IV of an anxiolytic preparation comprises all studies done after marketing. Specialized complementary studies allow to better define psychopharmacological profile: reaction to provoked stress, anxiolytic and sedative components, correlation blood levels - clinical effects, studies in elderly patients, mixed anxiety-depression syndromes. Surveillance studies are aimed to detect as soon as possible rare and serious adverse reactions. According to the situation the following studies are undertaken: system of data collection and processing for spontaneous reports, prospective follow-up studies of a large group of patients to detect only serious events, intensive follow-up to detect any potentially interesting event. Studies of interactions: systematic studies (alcohol, hypnotics) or sporadic spontaneous reports. Large multicentric uncontrolled studies may have an interest if they are done with an heuristic purpose, in order to use descriptive statistical tools, to generate hypotheses which should be independently confirmed afterwards.