title: Successful Re-administration of Low-dose of Methimazole (MMI) in Graves' Disease Patients Who Experienced Allergic Cutaneous Reactions to MMI at Initial Treatment and Had Received Long-term Propylthiouracil (PTU).
abstract: Objective When patients with Graves' disease show severe allergic cutaneous reactions, physicians often suggest that they undergo radioiodine therapy instead of receiving propylthiouracil (PTU), another antithyroid drug, because anti-neutrophil cytoplasmic antibody (ANCA) -related vasculitis can occur with PTU, especially with long-term use. However, some patients refuse radioiodine therapy and chose PTU. Sometimes PTU treatment may be prolonged. Since the frequency of adverse effects of methimazole (MMI) is dose-related, there is a possibility that we can re-administer a low dose without adverse effects to patients well-controlled with PTU who once experienced an allergic reaction to MMI. Methods I prospectively re-administered a low dose of MMI to patients who previously experienced an allergic reaction to MMI at initial treatment. The dose of re-administered MMI ranged from 5 mg twice a week to 5 mg daily. Patients Nine patients with Graves' disease who developed urticaria at initial treatment with MMI and had been treated with PTU for 6 to 21 years were recruited. Results Eight of the 9 patients were successfully controlled with MMI without allergic cutaneous reactions. Only one patient felt itchiness 2 days after switching to MMI. However, skin change was not observed. Conclusion If the patients show allergic cutaneous reactions as a side effect of MMI at the initial treatment for Graves' disease, then there is a strong possibility that such patients can tolerate a low dose of MMI without adverse effects after the disease activity has subsided.
authors.affiliation: Kubota Thyroid Clinic, Japan.
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Kubota
mesh_terms: D000328:Adult; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic; D013956:Antithyroid Agents / Q000008:administration & dosage* / Q000009:adverse effects* / Q000627:therapeutic use; D004334:Drug Administration Schedule; D003875:Drug Eruptions / Q000209:etiology*; D005260:Female; D006111:Graves Disease / Q000188:drug therapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008713:Methimazole / Q000008:administration & dosage* / Q000009:adverse effects*; D008875:Middle Aged; D011441:Propylthiouracil / Q000009:adverse effects / Q000627:therapeutic use*; D014657:Vasculitis / Q000139:chemically induced / Q000276:immunology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D013956:Antithyroid Agents; D007457:Iodine Radioisotopes; D008713:Methimazole; D011441:Propylthiouracil