thyroid drugs Flashcards
most thyroid hormone is in which form?
T4
what is the predominant for of thyroid hormone in the blood?
thyroxine binding globulin (TBG)
in the absence of thyroid hormone, is gene txn repressed or upregulated?
txn is repressed
what is the active ligand of thyroid hormone?
T3
where does conversion of T4–>T3 occur?
for activation of active form of hormone to occur, must be deiodinated intracellularly
high concentrations of what regulate thyroid hormone synthesis?
- T3 & T4
2. high concentrations of iodine
high concentrations of iodine _____thyroid synthesis, low concentrations of iodine _______thyroid synthesis
high concentrations of iodine inhibit thyroid synthesis, low concentrations of iodine promote thyroid synthesis
thyroid hormones ______beta receptors, _____alpha receptors
increase beta receptors,
decrease alpha receptors
thyroid effect on GI?
increase secretions and motility
does thyroid stimulation or repression result in prevention of accumulation of glycosaminoglycans in interstitial space (prevents edema)
thyroid upregulation
heat intolerance is assc’d with hyper or hypo thyroidism?
hyperthyroidism
skeletal muscle catabolism is assc’d with hyper or hypo thyroidism?
hyperthyroidism
myxedema is assc’d with hyper or hypo thyroidism?
hypothyroidism
how can respiratory occur in hyperthyroidism?
high RR + muscle catabolism
what is the thyroid hormone replacemnt tx of choice?
levothyroxine (T4)
AE: restlessness, insomnia, accelerated bone maturation
AE of administration of thyroid preparations to children
AE: nervousness, heat intolerance, palpitations, tachycardia, weight loss
AE of administration of thyroid preparations to adults
AE: A fib, osteoporosis
AE of administration of thyroid preparations to elderly
which thyroid preparation has a short half life, but is more potent?
liothyronine (T3)
low TSH, high T3 & T4
Grave’s disease
which drug has a black box warning for causing fatal hepatitis?
Propylthiouracil (PTU)
if you have to use a thioamide on a pregnant lady, which is the better choice? why?
PTU
more is bound to plasma proteins–>less likely to cross placental barrier
which thioamide to use in the case of thyroid storm?
PTU
has faster absorption than methimazole
AE: Metallic taste, sore gums/teeth, “like you have a cold” with HA, sneezing, cough; skin lesions; hypersensitivity, angioedema, laryngeal edema;
Lugol’s Solution/ Potassium Iodide
which drug inhib proteolysis of Tgb ?
Lugol’s Solution/ Potassium Iodide
the most common AE of hypothyroidism is assc’d with?
radioactive iodine
what antithyroid agent is assc’d with aplastic anemia
perchlorate
what are the key drugs that are used for cardioprotection with thyroid storm?
propranolol, diltiazem, barbituates, bile acid sequestrants
what can you use to control tachycardia in asthmatic?
Diltiazem (CCB)