The Double-Edged Sword of Methimazole: Managing Graves' Disease with a Twist

This case study highlights a rare but serious risk of methimazole-induced thrombocytopenia in a 40-year-old female with Graves' disease (GD). After starting methimazole therapy, the patient developed severe thrombocytopenia, evidenced by a platelet count drop to 9,000/µL, alongside improving hyperthyroidism symptoms. Despite initial treatment with platelet transfusion and steroids, the temporal link to methimazole and exclusion of other causes led to a diagnosis of methimazole-exacerbated immune thrombocytopenia. The study emphasizes the need for clinicians to be vigilant for drug-induced thrombocytopenia in hyperthyroid patients, especially when new bleeding symptoms arise, and suggests considering alternative GD treatments like radioactive iodine therapy or surgery.