Thyroid Hormones

Question 1

Food, antacids, calcium products and iron

Answer 1

Decrease absorption of T4 only (not T3)

Question 2

Absorption of T3 and T4

Answer 2

Orally

Question 3

Percentage of T4converted TO rT3

Answer 3

40 percent

Question 4

Thyroid hormone preparations

Answer 4

Levothyroxine T4
Liothyronine T3
Used in hypothyroidism and TSH suppression therapy and nontoxic goitre

Question 5

Higher dose of LT4 (25 to 40 percent)

Answer 5

Hypothyroid pregnant because fetal development

Question 6

IV therapy with myxedema

Answer 6

Because drug absorbed poorly with other routes

Question 7

Levothroxine

Answer 7

300 -400mg initially then 50 - 100mg daily

Question 8

Antithyroid agents

Answer 8

Inhibit hormone synthesis
Inhibit Iodide trapping
Inhibit hormone release
Destroy thyroid tissue
Beta blockers for peripheral manifestations

Question 9

Thioamides

Answer 9

Propyl thiouracil yes peripheral conversion
Carbimazole - prodrug (converted to methimazole) no peripheral conversion

Question 10

Clinical response takes long to appear in

Answer 10

Thyroid hormone prep

Question 11

Used as ttt in Thyroid storm because peripheral conversion

Answer 11

PTU

Question 12

In pregancy

Answer 12

Methimazole - 2nd and 3rd
PTU - 1st trimester

Question 13

Most serious but rare SE of thyroid hormones

Answer 13

Agranulocytosis

Question 14

Loss of hair in

Answer 14

Thioamide toxicity

Question 15

Taken orally

Answer 15

Iodide

Question 16

Mechanism of action of radioactive iodine

Answer 16

Rapidly absorbed and concentrated by thyroid
Plus emits cytotoxic beta rays

Question 17

The reason for benefit of KI dying even with continuous administration

Answer 17

Compensatory increase in TSH

Question 18

Has both hypo and hypert as SE

Answer 18

Radioactive iodin