Thyroid Drugs Staudinger

Question 1

What are the thyroid agents?

Answer 1

• Levothyroxine (T4)
• Liothyronine (T3)
• Liotrix (4:1 T4:T3)
• Thyroid desiccated

Question 2

What are the anti thyroid agents?

Answer 2

• radioactive iodine sodium
• methimazole
• potassium iodide
• propylthiouracil (PTU)

Question 3

Why is propranolol best in thyrotoxicosis?

Answer 3

• it can reverse some of the reduced systemic vascular resistance and inhibit peripheral conversion of T4 to the more biologically active T3

Question 4

How do thiocyante and perchlorate impact thyroid function?

Answer 4

• common environmental pollutant that disrupts normal thyroid function
• reduces uputake of iodine
• competitive inhibition of uptake at sodium iodide symporter

Question 5

What conversion does propranolol inhibit in peripheral tissues?

Answer 5

• prevents conversion of T4 to T3 in peripiheral tissues
• best tx for thyrotoxicosis

Question 6

How does Amioidarone cause thyrotoxicosis?

Answer 6

• thyroid tissue destruction occurs
• patients started on this need baeline TSH, T3 and T4
  
  • repeat every 6-12 months
• amiodarone has 50x higher amount of iodine in it needed for adults resulting in inc. in thyroid hms

Question 7

When is Methimazole used and how does it work?

Answer 7

• anti thyroid ued to treat hyperthyroidism, it blocks iodide organification, inhibits thyroperoxidase
• agranulocytosis, leukopenia, thrombocytopenia, aplastic anemia, liver inflammation

Question 8

Potassium Iodide uses?

Answer 8

• tx for hyperthyroidism, iiodine deficiency, can be used with methimizole to prepare for removal of thyroid
• also used to protect from radiation exposure as itshrinks the thyroid gland and decreases hm production
  
  • doesn’t cause irregular hb

Question 9

PTU uses?

Answer 9

Graves disease, toxic multinodular goiter, intolerant of methimazole, preparing for thyroidectomy

Question 10

PTU MOA?

Answer 10

• inhibits synthesis of thyroid hormones in hyperthyroidism
• inhibitis thyroxine to triiodothyronine in peripiheral tissues
  
  • doessn’t inactivate preexisting T3 or T4

Question 11

Levothyroxine use, AE’s from excessive dosing?

Answer 11

• Manufactured form of T4 that gets converted to T3
• used for hypothyroidism
• excess dose:
  
  • weight loss
  • can’t tolerate heat
  • sweat
  • anxiety
  • basically hyeprthyroidism sx

Question 12

What drugs impair levothyroxine absorption?

Answer 12

• antacids
• iron
• anti ulcer sucralfate
• cholestyramine
• orlistat
• ppi

Question 13

What is Radioactive Iodine used for, AE’s, contraindication?

Answer 13

• Therapy for thyroid cancer
• radiation destroys the gland and kills cells via taking up the iodine
• little effect on the body and contraindicated in pregnancy