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NURS 572 Pharm 57
Pharm Ch 57 thyroid drugs
Question | Answer |
---|---|
physiology of thyroid gland | uses enzyme peroxidase to trap inoranic iodine, which then combines with tyrosine to for T3 and T4 |
T3 | triiodothyronine |
T4 | tetraiodothyronine |
functions of thyroid hormone | increase metab, generate heat, stimulate heaert (HR, FoC, CO), promote growth/development (esp brain, NS, sk mus) |
endocrine control of thyroid | hypothal --- ant pit ---thyroid --- T3/T4 |
hypothyroid diseases | in non-pregnant adults --> myxedema. can be in pregnant women, infants. |
hyperthyroid diseases | Graves (TSIs autoimmune hyper-thyroid secretion), Plummer's disease (toxic nodular goiter), thyrotoxicosis |
What is Hashimoto's hypthyroiditis | usually auto-immune when iodine is not deficient. puffy, pale, alopecia, cool/dry skin, slowed metab, cold intolerance |
what is cretinism | hypothyroidism in children --> mental/physical retardation |
Grave's Disease | TSIs bind thyroid --> oversecretion T3/T4 --> wakeful, warm/moist skin, tachy, heat intol, inc appetite with dec weight, poss exophtalmos/goiter |
thyroid storm/thyrotoxicosis | extreme hyperthyroidism with extreme manifestations |
Plummers disease | adenoma --> hyperthyroidism --- same manifestations without exophthalmos |
drugs for hypothyroidism | levothyroxine T4, iodothyronine T3 |
what is preferred drug for hypothyroidism | levothyroxine |
what are ADRs of levothyroxine | Warfarin potentiated --> increased metabolism of clotting factors. Sympathomimetic --> potentiate cardiac effects |
What 3 drugs will increase metabolism of levothyroxine | phenytoin, riampin, carbemazepine |
What thyroid drug is rarely used due to $$$ and shorter duration | liothyronine T3, which has same interactions as T4 |
how do we treat myxedema | quick admin of IV T3/T4, then oral. concurrent corticosteroids. |
name 2 drugs to treat hyperthyroidism | PTU propylthiouracil, methimazole |
do drugs that tx hyperthyroidism destroy pre-formed thyroid? | no, these drugs only affect the synthesis of NEW hormone |
propylthiouracil MOA | blocks several steps in the oxidation of iodide and coupling of tyrosine. ALSO inhibits peroxidase enzymes. ALSO decreases peripheral conversion of T4-->T3 |
propylthiouracil ADRs | rare agranulocytosis (CBC/diff). dose related hypothyroidsim |
methimazole MOA | same as propylthiouracil (shuts down hormone synthesis) EXCEPT no action in peripheral conversion of T4-->T3 |