Iodine intake

Iodine activation and tyrosine iodination

coupling

freed

adjust

5/5' position of loop I and loop II, T4 deiodination → more active/weaker T3

Easy to absorb when taken orally

Parenteral administration in severe myxedema

Half-life>=1d

Can enter the placenta and breast milk, use with caution during breastfeeding and pregnancy

Liver and renal metabolism, renal excretion

Commonly used clinical levothyroxine sodium tablets

Maintain normal growth and development

Promote metabolism and thermogenesis

Improve the responsiveness of the body's sympathetic-adrenal system

TR is a nuclear receptor

Non-genetic effects (membrane)

Hypothyroidism

simple goiter

other

excess

treat

thiouracils

imidazoles

The thioamide group is a common structure & active group

Inhibits thyroid hormone synthesis: affects tyrosinase iodination coupling

Inhibits the conversion of T3 to T4 in peripheral tissues

Attenuates β-receptor-mediated glucose metabolism

Immunosuppressive effects: Reduce thyroid stimulating immunoglobulin/TSI levels

Medical treatment of hyperthyroidism

thyroid storm

Preparing for thyroid surgery

gastrointestinal reactions

allergic reaction

agranulocytosis

Goiter and hypothyroidism

Use with caution in lactation and pregnancy, and contraindicated in patients with nodular goiter, hyperthyroidism, and thyroid cancer.

Drugs that suppress thyroid function may increase their effects when used together with thioureas

Iodine delays the onset of action and should not be used together