Which medication is the first-line treatment for hyperthyroidism?

Methimazole is considered the first-line treatment for hyperthyroidism, particularly in cases related to Graves' disease. This medication works by inhibiting the enzyme thyroid peroxidase, which is crucial for the synthesis of thyroid hormones. By blocking this enzyme, methimazole decreases the production of thyroxine (T4) and triiodothyronine (T3), leading to a reduction in the symptoms associated with hyperthyroidism.

The preference for methimazole over other treatments stems from several factors, including its potency and dosing convenience, as it is typically administered once daily due to its longer half-life. Additionally, methimazole has a more favorable side effect profile when compared to some alternative treatments, like propylthiouracil, which can cause more liver toxicity and requires more frequent dosing.

While other treatments, such as iodine solutions or levothyroxine, may play roles in managing thyroid-related conditions, they are not considered first-line for hyperthyroidism itself. Iodine solutions are sometimes used for acute management or preparation for surgery, whereas levothyroxine is utilized to replace thyroid hormone in hypothyroid situations rather than reduce thyroid hormone levels. Thus, methimazole's mechanism of action and safety profile solidify