Piperacillin/tazobactam induced immune-mediated anaemia and thrombocytopenia

Piperacillin/tazobactam (PTZ) is known to cause cytopenia but case reports on PTZ causing combined haemolytic anaemia and thrombocytopenia are scarce. We report on a 56-year-old male who developed severe, immune-mediated thrombocytopenia and anaemia during two treatment episodes with PTZ. After the first exposure, his blood count rapidly returned to normal after discontinuation of PTZ. One year later, in the context of an unintentional re-challenge with PTZ, the level of red blood cells and platelets dropped again causing acute haemolytic anaemia and immune thrombocytopenia. Recovery was delayed after discontinuation of PTZ. PTZ should be considered as a potential cause of immune-mediated bicytopenia.