The major and minor side effects of the antithyroid drugs are listed in Fig. 17.49. All patients treated with carbimazole, methimazole (carbimazole is rapidly converted to methimazole in the body), and propylthiouracil should be warned of the risks of leucopenia leading to agranulocytosis ΓÇô presenting as a sore throat or ulcerated mouth. For medicolegal reasons, this warning should be conveyed to patients in writing, and should be noted in the patients' notes and in the letter to their general practitioner. Patients should be warned to discontinue the drug if these signs occur and to go to their doctor for a total and differential white blood cell count. When the drugs are discontinued, the blood picture rapidly returns to normal, providing that action is taken early.
