🔴 Mechanism of Action 🔴

🔺 Antithyroid Drugs :-

🔸1. Thioamides (antithyroid drugs) Inhibit hormone synthesis.

Thioamides bind to thyroid peroxidase and prevent the oxidation of iodide and iodotyrosyl residues , thereby ;

i) Inhibit iodination of tyrosine residues in thyroglobulin.

ii) Inhibit coupling of iodotyrosine residues to form T3 and T4.

🔸2.Inhibit iodide trapping (ionic inhibitors)
These ionic inhibitors inhibits iodide trapping by Sodium Iodide Symporter (NIS) into the thyroid gland.

Perchlorate is 10 times more potent than thiocynate in blocking NIS , while nitrate is very weak. So, these ions are toxic and not clinically used.

🔸3. Inhibit hormone synthesis (Iodine and Iodides)

Excess of iodide inhibits it's own transport into thyroid cells by interfering with expression of NIS on the cell membrane .

Reduction in T3 & T4 synthesis by this mechanism called Wolf- Chaikoff effect.

🔸4.Destroy thyroid tissue by Radioactive Iodine.

131 I (iodine) emits gamma rays as well as beta particals shows destructive effect on thyroid cells.

👉 Note :- The image of synthesis ,storage and secretion of thyroid hormone is given below , by using this image you can easily understand mechanism of Thyroid inhibitors.

🔴ADRS OF HYDROXYCHOROQUINE🔴

➡️blurred vision changes, which may be permanent in some cases
➡️heart disease, including heart failure and issues with your heart rhythm; some cases have been fatal
➡️ringing in your ears or hearing loss
➡️angioedema (rapid swelling of your skin)
➡️severe bronchospasm
➡️sore throat
➡️severe hypoglycemia
➡️unusual bleeding or bruising
➡️blue-black skin color
➡️muscle weakness
➡️hair loss or changes in hair color
➡️abnormal mood changes
➡️mental health effects, including suicidal thoughts