Bezafibrate-induced anaphylactic shock: Unusual clinical presentation

We report a case of a patient who suffered generalized urticaria, chest tig htness, wheezing, nausea, vomiting, hypotension, and loss of consciousness. Two hours earlier she had taken Eulitop Retard((R)) following lunch. She h ad tolerated all the implicated food after the reaction. Allergy evaluation revealed intense positive responses to intradermal tests with bezafibrate active component and Eulitop Retard((R)) (skin tests in control subjects we re negative). Specific IgE tests (RAST) to Eulitop Retard((R)) were negativ e. An IgE mechanism is suggested to be responsible for this adverse reaction o n the basis of the positive skin tets. The delayed onset (two hours) of thi s anaphylactic shock is unusual. Although infrequent, it may be caused by t he specific pharmacokinetic characteristics of this drug, which is a slow r eleasing agent: mainly absorbed in the gut. The drug was taken just after l unch, and this concomitant food ingestion could also have produced a delay in gastric drainage and a retarded drug absorption. An IgE-mediated acceler ated type reaction could also explain this delay. Apparently the patient re acted after the first contact to the drug, and the absence of a sensitizati on period is not usual in this type of immune reponse. Finally, we recommen d the performance of prick and intradermal skin tests prior to any systemic challenge when allergic reactions to fibric acid derivatives are suspected .