noun. a decrease in how many specific neutrophils (white blood cells), generally stemming from an immune response to a narcotic or some kind of substance or the lethal effect such a chemical has on bone marrow, thereby causing neutrophils to fall. Agranulocytosis results whenever the number of white blood cells falls beneath 200 per millimeter or whenever the entire amount of these cells fall beneath 500 per millimeter. The health problem causes weakening of immune responses and renders people into a state of sensitivity toward illnesses that take advantage of such situations. Psychotropic chemicals, such as clozapine, and also antipsychotic drugs can elicit this disorder
AGRANULOCYTOSIS: "Agranulocytosis is sometimes caused as a result of taking antithyroid medications."