antithyroids Flashcards

1
Q

levothyroxine: class

A
  • T4
  • thyroid H
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2
Q

levothyroxine: indication

A
  • thyroid H replacement
  • hypothyroidism
  • cretinism
  • myxedema coma
  • simple goiter
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3
Q

levothyroxine: MOA

A
  • Replacement of or supplementation to endogenous thyroid hormones.
  • Principal effect is increasing metabolic rate of body tissues:
    • Promote gluconeogenesis,
    • Increase utilization and mobilization of glycogen stores,
    • Stimulate protein synthesis,
    • Promote cell growth and differentiation,
    • Aid in the development of the brain and CNS.
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4
Q

levothyroxine: ADR

A
  • thyrotoxicosis:
    • S/S: tachycardia, angina, tremor, nervousness, insomnia, hyperthermia, heat intolerance, sweating
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5
Q

levothyroxine: nursing implications

A
  • contraindicated: recent MI, hyperthyroidism
  • inform pt about thyrotoxicosis and the S/S
  • if taking a H2 receptor antagonist, PPI, iron, antacid, calcium supplements, take them 4 hours apart from levothyroxine
  • obtain tests of free T3 and T4
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6
Q

methimazole: class

A
  • antithyroid
  • thionamide
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7
Q

thionamide: MOA

A
  • block synthesis of thyroid hormone
    • but does not destroy exhisting stores of thyroid hormone, so may take 3-12 weeks to get to a therapeutic state
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8
Q

methimazole: indications

A
  • hyperthyroidism:
    • Graves dz
    • given with radiation therapy
    • can be given to suppress thyroid H production after thyroid surgery
    • given if pt in thyrotoxic crisis
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9
Q

methimazole: SEs

A
  • rash
  • drowsiness
  • headache
  • hypothyroidism
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10
Q

methimazole: ADRs

A
  • agranulocytosis: dramatic reduction in granulocytes
    • sore throat, fever
  • neonatal: hypothyroidism, goiter, cretinsim
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11
Q

methimazole: nursing implications

A
  • contraindicated: 1st trimester of pregnancy
  • take daily at same time each day
  • monitor weight
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12
Q

propylthiouracil (PTU): class

A
  • antithyroid
  • thionamide
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13
Q

PTU vs. methimazole

A
  • PTU can cause severe liver injury
  • PTU has a shorter half life
  • PTU crosses the placenta less readily
  • PTU blocks conversion of T4 to T3 in the periphery
  • PTU is more toxic
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14
Q

PTU: indications

A
  • hyperthyroidism in:
    • pregnant pts during the 1st trimester
    • pts experiencing a thyroid storm (since it can work in the periphery)
    • pts who are intolerant of methimazole
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15
Q

PTU: SE

A
  • rash
  • drowsiness
  • headache
  • hypothyroidism
  • arthralgia
  • paresthesia
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16
Q

PTU: ADRs

A
  • liver injury
  • agranulocytosis
17
Q

PTU: nursing implications

A
  • only use during first trimester of pregnant otherwise mom and baby can be at inc risk of liver injury
  • take daily at same time every day
  • monitor weight
18
Q

radioactive iodide (I-131): class

A
  • antithyroid
19
Q

radioactive iodide: indications

A
  • hyperthyroidism: used to destroy thyroid tissue to produce clinical remission w/o complete destruction of the thyroid gland
    • full effects in 2-3 mos
  • thyroid cancer
20
Q

radioactive iodide: MOA

A
  • emits beta particles to penetrate any type of physical barrier
  • do not travel outside thyroid
21
Q

radioactive iodide: advantages

A
  • low cost
  • pt spared risk, discomfort, expense of thyroid surgery
  • death is rare
  • no tissue other than thyroid is injured
22
Q

radioactive iodide: disadvantages

A
  • effect is delayed
  • assoc with risk of delayed hypothyroidism from excessive dosage and occurs in 90% of pts w/in 1st year
  • do not use in children, pregnant women, breast feeing mothers
    • can cause a fetus to develop an immature thyroid is exposed after 1st trimester
23
Q

radioactive iodide: nursing implications

A
  • women must have a negative pregnancy test
24
Q

potassium iodide: class

A
  • nonreactive iodine
    • AKA Lugol’s Solution
25
Q

potassium iodide: MOA

A
  • iodide has a paradoxical effect on thyroid when given in high conc
    • prevents iodine uptake by thyroid
    • inhibit thyroid hormone synthesis by suppressing both iodination of tyrosine and coupling iodinated tyrosine residues
    • high conc of iodine inhibit release of thyroid hormone into the blood
      • all work to dec levels of T3 and 4
26
Q

potassium iodide: indication

A
  • hyperthyroidism
    • in individuals to suppress thyroid fcn in prep for thyroidectomy
  • thyrotoxic crisis
27
Q

potassium iodide: ADRs

A
  • iodism
    • S/S: brassy taste, burning sensation in outh, soreness in teeth/gums, frontal headache, nasal inflammation, salivation
  • overdose can injure GI tract–vomiting, diarrhea, pain
28
Q

potassium iodide: nursing implications

A
  • obtain thyroid fcn test
  • dilute strong soln with fruit juice to inc palatability