Acute agranulocytosis after prolonged high-dose usage of intravenous dipyrone--a different mechanism of dipyrone toxicity?

Two seriously injured trauma patients presenting with intense and progressive neutropenia are described. Bone marrow examination in both cases showed virtually absent granulopoiesis but normal erythropoiesis and megakaryopoiesis, allowing the diagnosis of acute agranulocytosis. Discontinuation of only one drug (dipyrone) with no further treatment was required for normalization of blood parameters. The association of dipyrone with neutropenia is still debatable. The recent medical literature on dipyrone generation of agranulocytosis is reviewed.