[Treatment of clozapine-induced agranulocytosis using granulocyte colony-stimulating factor]

A 20-year-old woman had for the preceding 11 weeks been receiving clozapine (225 mg/d) for an endogenous psychosis when she developed a urinary tract infection with fever. The blood count showed 2100 white cells/microliter without any neutrophils, the count having been normal 5 days previously. Physical examination was normal except for a fever of 39 degrees C and parodontitis. The red cell count was 3.9 mill/microliters, platelet count 443,000/microliters. Bone marrow biopsy revealed almost complete stop of proliferation and maturation in granulocytopoiesis so that granulocyte colony-stimulating factor (300 micrograms daily subcutaneously) had to be administered in addition to supportive measures. The granulocyte count at first fell to 1400 cells/microliter, but nine days after starting the drug myeloblasts, promyelocytes and myelocytes reappeared in peripheral blood for the first time. On the tenth day, administration of the growth factor was discontinued. An overshoot granulocytopoiesis occurred in bone marrow on the 13th day; on the 22nd day after treatment had been started the patient had a normal blood picture and was discharged.