RESUMO
BACKGROUND: The methimazole has long been used for treating Graves' disease to decrease thyroid hormone production and obtain a thyroid normofunction, but this drug has also immunosuppressive and immunomodulation effects. OBJECTIVE: To analyze in patients with Graves' disease treated with methimazole and allergic rhinitis, the clinical evolution of the allergic rhinitis with the immunosuppressive and immunomodulation effects of the methimazole. PATIENTS AND METHODS: A comparative and observational study was done in the Mexico's General Hospital, in twenty-six patients with Graves' disease treated with methimazole 10 mg, thyroid profile was done, and when subjects obtained a thyroid normofunction continued with the same doses of methimazole and received also 12.5 mcg/day of levothyroxine. All the patients were diagnosed with allergic rhinitis, and they were divided into two groups (11 females and 2 males each). Both groups continued with the same treatment of methimazole and levothyroxine, but group II was given also antihistamines H1 of second-generation (loratadine) daily, and specific immunotherapy during six months. We described and compared the clinical evolution of the allergic rhinitis of the two groups with the treatment. RESULTS: In the group I, changes in the clinical evolution of the allergic rhinitis after six months were not observed. In the group II, by week 10 the symptoms of the allergic rhinitis were controlled in 80% of the patients, and by week 14 all the patients of this group were asymptomatic. CONCLUSIONS: In patients with allergic rhinitis and Graves' diseases with methimazole-thyroid normofunction we observed that there is not influence of methimazole on clinical evolution of the allergic rhinitis.