Thyroid hormone replacement

Question 1

name TH hormones

Answer 1

levothyroxine

liothyronine

Question 2

TH hormones indications

Answer 2

• primary hypothyroid

- hypothyroid secondary to hypopituitary

Question 3

MOA TH hormones

Answer 3

• levo = t4

- lio = t3 (shorter half life and quicker onset and offset. only in emergency

Question 4

SE TH hormones

Answer 4

• usually if too high a dose so sx of hyperthryoid

Question 5

warnings for TH hormones

Answer 5

• increase HR and metabolism - can precipitate cardiac ishcaemia in people with coronary artery disease - start replacing cautiously.
• hypopituitary - start steroids BEFORE thyroid replacement to avoid addisonian crisis

Question 6

interactions of levothyroxine

Answer 6

• reduced by antacids, ca and iron. seperate by 4hrs.
• increase dose if cyp450 inducers
• due to levo increasing metabolism - insulin or oral hypoglycaemic requirements can increase
• enhances effects of warfarin