Idiosyncratic drug reactions: the reactive metabolite syndromes

Idiosyncratic drug reactions are unpredictable reactions that can result in significant morbidity and mortality. Severe reactions are often characteri sed by fever and internal organ involvement. Despite progress in the identi fication of reactive metabolites believed to be the cause of idiosyncratic reactions, the basic mechanisms remain elusive, Furthermore, because of the lack of consensus regarding definition of these syndromes, reporting, and therefore epidemiological data, are often unreliable. Research is needed to explore further the pathophysiology of these reactions, so that better dia gnostic tests and treatment methods can be developed.