thyroid drugs Flashcards
1. Describe the synthesis and release of thyroid hormone and describe the relationship between T3 and T4 in terms of production, potency, protein binding, and metabolism. 2. Describe the rationale for the approaches used in the pharmacological treatment of hyperthyroidism. 3. List the prototype oral drugs used to treat hyperthyroidism, describe their mechanism of action and list their major side effects and clinical uses. 4. Explain the source and function of circulating iodide and its dual a
Levothyroxine
Thyroid replacement
liothyronine
Thyroid replacement
liotrix
Thyroid replacement
thyroglobulin
Thyroid replacement
DOC for hypothyroidism
levothyroxine
levothyroxine mimics
T4
liothyronine
T3
issue with generic levothyroxines
different generics are absorbed at different rates
rapid onset, short DOA Thyroid replacement
liothyroxine
can cause myxedema coma
liothyroxine
can be cardiotoxic
liothyroxine
mixture of T3 and T4
liotrix
purified hog thyroid extract
thyroglobulin
instable, variable product that can cause antigenic issues
thyroglobulin
most potent Thyroid replacement
liothyroxine
general SE of Thyroid replacement drugs
hyperthyroidism
CV side effects
population needed to be cautious with with Thyroid replacement drugs
elderly, esp with CV disease
MOA of Propylthiouracil
interferes with deionization of T4 into Active T3
organification
creating I2 out of ionized Iodine
coupling
DIT to T4 step
hormone created by the thyroid
T4
active thyroid hormone
T3
MOA of thioamides in general
prevents synthesis of active T3 by blocking organification, coupling or deiodination
SE of thioamides in general
skin rash, headache, nausea, leukopenia, agranulocytosis
MOA of iodides
decreases the size and vascularity of the hyperplastic thyroid gland. blocks organification and release of T4
drug to use before thyroid removal
iodide
contraindications to iodides
use before I 131
increased iodine stores will
delay thionamide onset
withdrawal of iodide therapy can
precipitate thyrotixicosis
iodide drugs (3)
lugol’s solution, KI Sodium ipodate
used to asess thyroid responsiviness
Radioactive iodide
destroys iodide tissues
I 131
suppresses clinical sx of hyperthyroidism
propranolol
use of propranolol in thyroid dx
shortterm until definitive therapy
steps of Thyroid hormone biosynthesis
trapping, organification, incorporation, coupling, proteolysis and release
intermediate thyroid hormone products
thyroglobiln MIT DIT T4 T3
T4 converted to T3 where?
bloodstream
amino acid used in thyroid hormone sythesis
thyrosine
effect of THs and catcholamines
potientate each other
