treatment of thyroid diseases Flashcards
describe the process of regulation thyroid hormone
hypothalamus release TRH
TRH will stimulate pituitary to release TSH
TSH will release THYROID HORMONE
thyroid hormone will negatively inhibit TSH and TRH
what are the stuff we can inhibit in case of hyperthyroidism ?
peroxidase enzyme which is responsible coupling and iodination
inhibit the release of thyroid
inhibit the uptake of iodine
what drugs inhibit the peroxidase enzyme?
thioamides
what drugs inhibit the uptake of iodine?
potassium iodide
how do we inhibit the release of thyroid hormone?
lithium
what is the normal level of TSH?
0.4 - 4.0 mIU/L
what are some drugs that inhibit the release of TSH?
D2 receptor agonist
GHIH analogs –> octreotide
glucocorticoids
metformin
what are some dopamine agonists ?
dopamine
dobutamine
levodopa
cabergoline
bromocriptine
these inhibit prolactin and GH ( in acromegaly ) and TSH
what are some stuff that increases TSH secretion?
dopamine receptor antagonist ( D2 receptors )
what are some dopamine receptor antagonists?
metoclopramide
domperidone
what are the manifestation of hyperthyroidism ?
nervousness
emotional
disturbance
weight loss
heat intolerance
palpitations
proximal muscle weakness
increase frequency of bowel movements
irregular menses
what is grave disease?
autoimmune disease where antibodies that are similar to TSH bind to the TSH receptor and stimulate more production thyroid hormone and the release of it
what are the characteristics of graves disease?
thyroid enlargement
exophthalmos
what are the none pharmacological therapy for hyperthyroidism?
surgery
thyroidectomy
when do you consider surgery?
large thyroid gland
severe ophthalmopathy
lack of remission on antithyroid drug
what are the drugs used for preparation of thyroidectomy?
thionamides –> inhibit production of T3,T4
beta blockers/ propranolol –? relief symptoms and inhibit T3 production
supersaturated iodine–> reduces gland vascularity
lethium carbonate –> block thyroid release
dexamethasone/corticosteroid —-> reduces TSH levels and inhibit T4 to T3 conversion
what is wolff chaikoff effect?
when the body gets a large amount of iodine at once this will temporarily inhibit the thyroid synthesis due to inhibition of thyroid peroxidase
this will reduce the vascularity temporarily as well
what are the pharmacological treatments for hyperthyroidism?
antithyroid medications
iodides
adrenergic blockers
radioactive iodine
what are some antithyroid medications?
thionamides :
methimazole
propylthiouracil
what is the MOA of methimazole?
inhibit coupling of MIT AND DIT to form T3 AND T4
what is the MOA of propythiouracil ?
inhibit coupling
INHIBIT PERIPHERAL CONVERSION OF T4 to T3
more effective compared to methimazole because it works peripherally as well
which antithyroid drug is the choice for pregnant women?
propylthiouracil