Thyroid and AntiThyroid Agents Flashcards
What is Grave’s Disease?
Hyperthyroidism caused by stimulation of the TSH receptor by autoimmune antibodies.
Is T3 and T4 high or low in Grave’s Disease?
T3 and T4 are HIGH
Is TSH high or low in Grave’s Disease?
TSH is LOW
Propylthiouracil
1) Mechanism of Action
2) Use
3) Adverse Reactions
1)Thioamides/Thioureylenes-inhibits thyroid peroxidases which inhibits production of T3/T4 by decreasing oxidation of iodide, iodination of thyroglobulin, and coupling of MIT/DIT to form T3/T4
Also inhibits peripheral conversion of T4 to T3
2)Hyperthyroidism
3)Delayed HYPOthyroidism, Agranulocytosis (peroxidase in WBCs inhibited causing infections)
NO teratogenic effects
Methimazole
1) Mechanism of Action
2) Use
1) Thioamides/Thioureylenes-inhibits thyroid peroxidases which inhibits production of T3/T4 by decreasing oxidation of iodide, iodination of thyroglobulin, and coupling of MIT/DIT to form T3/T4
2) Hyperthyroidism
3) Delayed HYPOthyroidism, Agranulocytosis (peroxidase in WBCs inhibited causing infections)
* DO NOT USE in FIRST trimester of pregnancy!*
Potassium Iodide
1) Mechanism of Action
2) Use
1) Inhibits proteolysis and thus the release of T3/T4 from colloid
2) Hyperthyroidism, Prevent uptake of radioactive Iodide 131 after a nuclear accident
Radioactive Iodide 131
1) Mechanism of Action
2) Use
3) Adverse Reactions
1) Concentrates itself in the thyroid and causes localized radiation damage
2) Hyperthyroidism
3) Delayed hypothyroidism
* DO NOT USE in pregnant or nursing women*
Propranolol
1) Mechanism of Action
2) Use
1) Non-Selective Beta Adrenergic Antagonists/Blocker
2) Decrease Cardiovascular symptoms associated with hyperthyroidism
What is Hashimoto’s Disease?
Hypothyroidism caused by autoantibodies to thyroid cells causing thyroid destruction
Is T3 and T4 high or low in Hashimoto’s Disease?
T3 and T4 are LOW
Is TSH high or low in Hashimoto’s Disease?
TSH is HIGH
Name 4 causes of Primary HYPOthyroidism
1-Hashimoto’s MOST COMMON in US
2-Iodine Deficiency Most common in world
3-Destruction/Surgical Removal of the Thyroid
4-Congenital Least common
What environmental contaminant can cause drug-induced hypothyroidism?
Perchlorate-can be found in well water
Blocks Iodide uptake into thyroid follicular cells
Thyroxine/Synthetic T4
1) Use
2) Potency
3) Half Life
4) Adverse Reactions
1) HYPOthyroidism
2) 4x LESS potent than T3
3) Longer Half-life than T3 (about 7 days)
* *Converts to T3 in peripheral tissues**
4) Thyrotoxicosis (basically HYPERthyroidism symptoms), Cardiovascular stress
Triiodothyronine/Synthetic T3
1) Use
2) Potency
3) Half Life
4) Adverse Reactions
1) HYPOthyroidism
2) 4x MORE potent that T4
3) Shorter half life than T4 (about 1 day)
* More expensive*
4) Thyrotoxicosis (basically HYPERthyroidism symptoms), Cardiovascular stress
