Anti-thyroid agents are a group of medications used to treat hyperthyroidism (such as Graves' disease), including thionamides (such as methimazole and propylthiouracil) and iodides. These drugs primarily act on thyroid tissue, reducing the levels of thyroid hormones in the blood by inhibiting their synthesis (thionamides) or interfering with their release (iodides). They affect the biosynthetic pathway of thyroid hormones by influencing thyroid peroxidase activity or inhibiting iodine uptake. The response to these drugs may vary among individuals due to genetic variations, such as certain gene mutations that may affect the metabolism or efficacy of the medication, necessitating personalized treatment plans.