Anemia aplásica inducida por metimazol: presentación de caso

Introduction: Antithyroid drugs are one of the therapeutic alternatives in the treatment of Graves’ disease. However, it can generate severe but infrequent adverse effects at the hematological level, such as aplastic anemia, which has been associated with high doses of these drugs, although with reversal of this hematological condition when the drug is withdrawn. Case description: A 38-year-old woman with a history of Graves’ disease treated with methimazole, who consult for symptoms such as anterior epistaxis, petechiae, asthenia, and hyporexia. Pancytopenia is documented in the blood count, with a subsequent finding of bone marrow aplasia in bone marrow biopsy, without response to withdrawal of Methimazole and transfusion support. The patient subsequently died. Conclusion: The methimazole-associated bone marrow aplasia is uncommon and it´s associated with high doses of methimazole, in most cases withdrawal of methimazole leads to clinical and cellular recovery. However, in some patients hematological involvement persists with significant clinical repercussions up to fatal outcomes. Therefore, this case seeks to highlight the importance of monitoring for this adverse effect before starting this medication.