Neutropenia following acute chlorpromazine ingestion

A 5-year-old child is reported who, after an acute ingestion of chlorpromazine, developed an absolute neutropenia. The neutrophil count reached its nadir (210 cells/mm3) at 45 h postingestion. The child recovered and had a normal white blood cell count 17 d after ingestion. While neutropenia and agranulocytosis are not uncommon with chronic chlorpromazine therapy, neutropenia following an acute ingestion is unique but predictable in view of chlorpromazine's toxic effects on white cells. A white blood cell count on presentation of an acute chlorpromazine ingestion and at 24-48 h postingestion should allow detection of patients at risk for acute chlorpromazine-induced neutropenia.