Immunoallergic adverse effects of fluindione

Bleeding is the main adverse effect of all vitamin K antagonists. Fluindione, an indanedione derivative, can also have serious immunoallergic adverse effects. Several hypersensitivity reactions affecting various organ systems have been reported in detail in patients taking fluindione, mainly cutaneous, hepatic or renal disorders, often associated with fever. Cases of isolated kidney and liver damage have also been reported. Fluindione has been linked to cases of acute generalised exanthematic pustulosis. An immunoallergic mechanism is suspected, based on several factors, including the involvement of several organs, the types of damage, the chronological sequence of events, outcome after fluindione withdrawal, and cases of positive rechallenge. About a hundred reports of non-haemorrhagic adverse effects attributed to fluindione were recorded in the French pharmacovigilance database during the course of a single year (July 2008 to June 2009). In practice, when anticoagulant therapy with a vitamin K antagonist is needed, it is better to use warfarin, the best-assessed oral anticoagulant. If fluindione is nonetheless prescribed, the patient must not only be taught how to manage vitamin K antagonist therapy but also how to recognise signs of hypersensitivity.