Methimazole-induced agranulocytosis treated with recombinant human granulocyte colony-stimulating factor (G-CSF)

A 35-year-old female hematology technician with Graves' disease developed agranulocytosis a few days after starting therapy with Tapazole (methimazole). Because of a recent report of use of recombinant human granulocyte colony-stimulating factor (G-CSF) in patients with propylthiouracil-induced agranulocytosis, 5 micrograms/kg/day G-CSF was administered and her granulocyte count returned to normal after three doses, on the sixth day after the last dose of methimazole. We conclude that in patients with drug-induced agranulocytosis, the use of G-CSF, in addition to discontinuation of the offending drug, hastens recovery and reduces morbidity.