Agranulocytosis secondary to methimazole therapy: report of two cases.

Seventy-three cases of thyrotoxicosis were treated at Lloyd Noland Hospital with methimazole, propylthiouracil or both. Two cases of agranulocytosis occurred (2.7%) secondary to methimazole. Both responded to hospitalization, reverse isolation, and antibiotic coverage with complete recovery of the peripheral blood picture. The toxicity of methimazole is noted. The need for careful monitoring of blood counts during therapy and immediate discontinuance of the drug at the first clinical sign of granulocytopenia is stressed.