Extra Thyroid Flashcards
what is important to remember about ADRs for levothyroxine?
resemblance of hyperthyroidism, will increase clearance and decrease half life of T3 and T4
how is levothyroxine metabolized?
hepatic metabolism to active T3 when given oral T4 (different than compared to normal cell conversion)
what are the 4 goals of hypothyroidism tx?
alleviate patient symptoms
normalized TSH secretion
normalize T4 levels
avoid overtreatment (toxic)
what is hypothyroidism?
deficiency in thyroid hormones
what are symptoms and physical signs of hypothyroidism?
symptoms: weight gain (10-20 lbs), cold intolerance, fatigue, muscle cramps, depression
physical signs: rough/dry skin, swelling of face/hands/feet, hoarse voice, muscle weakness, dec HR
explain the process of thyroid hormone synthesis and release?
Hypothalamus releases NT on pit, which releases TSH on thyroid gland. Gland releases T4 and T3 (T4 is converted to T3 in the liver and muscle). T3 acts on target tissues. Both T4 and T3 provide neg feedback on pit and hypothalamus
what is the unit of desiccated thyroid hormones?
GRAINS
1 grain = 65 mg
what are some symptoms and physical signs of hyperthyroidism?
symptoms: weight loss with increased appetite, heat intolerance, heart palps, hyperactivity, polyuria
physical signs: inc hr, tremor, goiter, moist/warm skin, inc reflexes
describe use of hyperthyroidism meds in pregnancy
PTU is preferred during 1st trimester (can continue or switch to methimazole for remainder)
Methimazole CANNOT be used during 1st trimester
how many times per day is PTU given? compare this to methimazole?
PTU is given 3 times per day whereas methimazole is 1-2 times per day (10x more potent)
which hyperthyroidism drug inactivates conversion of T4 to T3 in the periphery?
PTU
what is DOA for methimazole vs PTU?
meth- 36-72 hrs
PTU- 12 hrs
what two baseline tests do you get on a pt before administering hyperthyroid meds?
CBC (ADR: agranulocytosis) and LFT (ADR: hepatotoxicity)
what is the best BB to use in thyrotoxicosis?
propranolol
