thyroxine (T4, Synthroid)
Thyroid hormone- synthetic
- act as agonist of thyroid hormone receptor (same effects as natural hormone)– inc. BMR, inc. HR and CO, stimulate protein synthesis
- used in treatment of hypothyroidism
- can be given oral, IM or IV
- children and pregnant women require higher dosing
- *potency of 1, half-life of 7 days, less expensive
- converted to T3 in peripheral tissues
- S/fx: thyrotoxicosis (nervousness, insomnia, increased BMR), stressful on CV system
- use cautiously in pts with CV disease and pregnant women
triiodothyronine (T3, Cytomel)
Thyroid hormone- synthetic
- act as agonist of thyroid hormone receptor (same effects as natural hormone)– inc. BMR, inc. HR and CO, stimulate protein synthesis
- used in treatment of hypothyroidism
- can be given oral, IM or IV
- children and pregnant women require higher dosing
- *potency of 4, half-life of 1 day, more expensive
- S/fx: thyrotoxicosis (nervousness, insomnia, increased BMR), stressful on CV system
- use cautiously in pts with CV disease and pregnant women
T4 + T3 (Thyrolar)
Thyroid Hormone
- act as agonist of thyroid hormone receptor (same effects as natural hormone)– inc. BMR, inc. HR and CO, stimulate protein synthesis
- used in treatment of hypothyroidism
- can be given oral, IM or IV
- children and pregnant women require higher dosing
- T4 is converted to T3 in peripheral tissues
- S/fx: thyrotoxicosis (nervousness, insomnia, increased BMR), stressful on CV system
- use cautiously in pts with CV disease and pregnant women
propylthiouracil (PTU)
Thioamide (thioureylene)- Oral tx for hyperthyroid
- inhibits thyroid peroxidase thus decreasing the oxidation of iodide, the iodination of thyroglobulin, and the coupling of MIT and DIT to form T3 and T4
- also inhibits the peripheral conversion of T4 to T3
- initial time course of action takes weeks b/c thyroid hormone stores must be depleted first
- S/Fx: skin rash, delayed hypothyroidism, agranulocytosis (not common but dangerous)
- works faster then MMI, but less potent and shorter DOA
- used in pregnant women during first trimester
- can be used in lactating mothers
- initially high doses that are tapered down
- need to observe for 12-18 months
methimazole (MMI)
Thioamide (thioureylene)- Oral tx of hyperthyroid
- inhibits thyroid peroxidase thus decreasing the oxidation of iodide, the iodination of thyroglobulin, and the coupling of MIT and DIT to form T3 and T4
- initial time course of action takes weeks b/c thyroid hormone stores must be depleted first
- S/Fx: skin rash, delayed hypothyroidism, agranulocytosis (not common but dangerous)
- more potent and longer DOA then PTU
- usually tried first but cannot use in first trimester of pregnant mothers-can be used in lactating mothers
- initially high doses that are tapered down
- need to observe for 12-18 months
potassium iodide
- oral tx of hyperthyroid
- inhibits release of T3 and T4
- time course of action is fast (days) but effects are transient (2-8 weeks)
- not rarely used alone
- S/Fx: readily reversed by discontinuing use, rashes, swollen salivary glands
- also used to prevent uptake of iodine 131 after nuclear accident
radioactive iodine
- oral treatment of hyperthyroidism
- concentrates in thyroid and causes localized radiation damage
- S/Fx: delayed hypothyroidism, radiation exposure
- time course of action is slow (weeks)
- do not use in pregnant women or nursing mothers
- can cause exacerbation of hyperthyroidism as thyroid is destroyed (causes massive release of hormone)
propranolol
Beta-adrenergic antagonist
- used to alleviate symptoms associated with inc. CV activity
- thyroid hormones inc. sensitivity of CV receptors to catecholamines
reverse T3
-biologically inactive thyroid hormone
thyroid follicular cell
- thyroid cells that surround amorphous colloid center
- endocytosis of thyroglobulin from colloid
- T3 and T4 is hydrolyzed from larger complex and free T3 and T4 diffuses into blood stream
thyroglobulin
- large complex of MIT, DIT that combines with iodine to form bound T3 and T4
- stored in colloid of thyroid
- hydrolyzed to form free T3 and T4
MIT/DIT
-bound within larger thyroglobulin complex and forms T3 and T4 when iodine binds to it
TBG (thyroxine binding globulin)
- large protein that binds T3 and T4 and helps transport through blood stream
- only free T3 and T4 are active
thyroid peroxidase
-within membrane that separates follicular cells and colloid of thyroid, oxidizes iodide to form iodine which is required to form T3 and T4 on thyroglobulin complex
primary hypothyroidism
- due to dysfunction of thyroid gland itself
- low T3, T4; high TRH and TSH
- AKA Hashimoto’s disease
secondary hypothyroidism
-due to dysfunction of the pituitary glad, and inability to stimulate thyroid to release hormone
tertiary hypothyroidism
-due to dysfunction of hypothalamus causing hypothyroid
myxedema
-severe hypothyroidism
myxedema coma
- extreme expression of severe long-standing hypothyroidism
- rare but life-threatening
thyrotoxicosis
- over dose of thyroid hormones
- nervousness, insomnia, increased BMR
Grave’s Disease
- stimulation of TSH receptor on thyroid gland by autoimmune antibodies
- high serum T3 and T4 (total and free)
- low TSH
- causes formation of goiter
- Symptoms: flushed, warm/moist skin, weak/tremulous muscles, tachycardia, inc. BMR, inc. appetite, exophthalmos, menstrual irregularities
- treatment: dec. synthesis and/or release of thyroid hormones
perchlorate
-environmental toxin that can inhibit the uptake of iodide by the thyroid follicular cells causing hypothyroidism
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Intro to Antimicrobials16
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Cell Wall Synthesis Inhibitors40
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Protein Synthesis Inhibitors24
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Antimetabolites7
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Antifungals11
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Antivirals16
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Insulin/Oral Anti-diabetic Agents26
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Thyroid/Anti-Thyroid Agents22
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Adrenocortical Steroids18
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Progestins, Estrogens, Androgens42
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Pharmacogenetics17
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Pituitary, Hypothalamic, Calcium Meds27
