title: The relation of initial methimazole dose to the incidence of methimazole-induced agranulocytosis in patients with Graves' disease.
abstract: The relation between the incidence of methimazole (methylmercaptoimidazole; MMI)-induced agranulocytosis and initial MMI dose was evaluated in a group of 514 patients with Graves' disease who were treated between 1995 and 2005. One hundred and forty-six (28.40%) patients had received an initial dose of 30 mg MMI and 277 (53.89%) patients had been treated with 15 mg MMI. Nine patients (1.75%) developed agranulocytosis due to MMI treatment. Six (4.11%) of 146 patients who received an initial dose of 30 mg MMI, two (4.54%) of 44 patients given an initial dose of 20 mg MMI, and one (0.36%) of 277 patients given an initial dose of 15 mg MMI developed agranulocytosis. There was a statistically significant difference in agranulocytosis incidence between patients receiving an initial dose of 30 mg MMI and those who received an initial dose of 15 mg. Although 8 (4.10%) of 195 patients in the high-dose group (20 mg or higher) developed agranulocytosis, only 1 (0.31%) of 319 patients in the low-dose group (15 mg or lower) did. In conclusion, the incidence of agranulocytosis with low-dose MMI therapy was ten times lower than that of the high-dose regimen.
authors.affiliation: Division of Diabetes, Metabolism and Endocrinology, Department of Medicine, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Tsuboi
authors.forename: Hajime
authors.initials: H
authors.lastname: Ueshiba
authors.forename: Masako
authors.initials: M
authors.lastname: Shimojo
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Natsuko
authors.initials: N
authors.lastname: Watanabe
authors.forename: Kaoru
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Rena
authors.initials: R
authors.lastname: Yuasa
authors.forename: Gen
authors.initials: G
authors.lastname: Yoshino
mesh_terms: D000293:Adolescent; D000328:Adult; D000380:Agranulocytosis / Q000139:chemically induced* / Q000453:epidemiology; D013956:Antithyroid Agents / Q000008:administration & dosage / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006111:Graves Disease / Q000188:drug therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D008713:Methimazole / Q000008:administration & dosage* / Q000009:adverse effects*; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D013956:Antithyroid Agents; D008713:Methimazole