Carbimazole-induced agranulocytosis--a report of 2 recent cases

Carbimazole is a useful antithyroid drug with a rare potentially fatal complication of agranulocytosis. We report 2 cases presenting with this problem. One was treated supportively with barrier nursing and broad spectrum antibiotics, and the other needed use of a haemopoietic growth factor, granulocyte colony stimulating factor (G-CSF). As it is indeed possible for thyrotoxic patients who developed agranulocytosis with carbimazole to have the same complication with propylthiouracil, once agranulocytosis had resolved, both patients were treated with radioiodine to maintain euthyroidism. Carbimazole-induced agranulocytosis usually spontaneously resolves within 1 to 2 weeks of stopping the drug. The use of haemopoietic growth factors to stimulate the proliferation and differentiation of progenitor cells, accelerates neutrophil recovery, as in our first case discussed. We recognise that agranulocytosis from carbimazole is a rare, life-threatening complication. Instead of awaiting spontaneous recovery, the use of haemopoietic growth factors certainly seems a justifiable option, with a promise of a reduction in morbidity and mortality.