Endocrine: Thyroid Flashcards
•Drugs to treat HYPOTHYROIDISM
a. Levothyroxine
b. Liothyronine, desiccated thyroid
c. Methimazole
d. Propylthiouracil (PTU)
e. Potassium iodide
f. Radioactive Iodine
a. Levothyroxine
b. Liothyronine, desiccated thyroid
•Drugs to treat HYPERTHYROIDISM
a. Levothyroxine
b. Liothyronine, desiccated thyroid
c. Methimazole
d. Propylthiouracil (PTU)
e. Potassium iodide
f. Radioactive Iodine
c. Methimazole
d. Propylthiouracil (PTU)
Thyroxine (T4)
• Longer half life ~ ? days
• Pro-hormone (?potency)
Thyroxine (T4)
• Longer half life ~ 7 days
• Pro-hormone (low potency)
? Potent (3-4 times more potent than T4)
T3
GOLD STANDARD:?
Thyroid Stimulating Hormone (TSH)
Other options:
T4
T3
Thyroid Stimulating Hormone (TSH)
◦ Thyroid Stimulating Hormone (TSH)
◦ Normal Range
◦ ? to ? milliunits/L per ATI
◦ Thyroid Stimulating Hormone (TSH)
◦ Normal Range
◦ 0.3 to 5 milliunits/L per ATI
Thyroid preparations are given to replace what the
thyroid gland cannot produce to achieve normal
thyroid levels (euthyroid to TSH?).
euthyroid
•USED TO TREAT: • Myxedema Coma a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
•MECHANISM OF ACTION: • Simply synthetic T4 (thyroxine) • Body will store and convert to T3 in ratios a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
◦ FIRST: Start low, go slow ◦ Overdose- “Hyperthyroidism a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
b. Liothyronine, desi
ADVERSE EFFECTS ◦ H eat intolerance ◦ E xcitement (insomnia) ◦ A ngina ◦ R estless ◦ T achycardia/Tremor a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
a. Levothyroxine
ADVERSE EFFECTS
HEART
◦ H eat intolerance ◦ E xcitement (insomnia) ◦ A ngina ◦ R estless ◦ T achycardia/Tremor
ADVERSE EFFECTS Continued ◦ Boxed Warning: FDA recommends not to use as treatment for obesity/weight loss ◦ Can see toxicity- concern with dysrhythmias like atrial fibrillation (and other organ issues too!) a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
Levothyroxine
ADMINISTRATION
◦ Start with a ? dose and increase based on TSH
◦ Check a pulse before giving (hold if >?)
◦ This drug requires an ? stomach (acidic pH)
◦ Give first thing in the ?
ADMINISTRATION
◦ Start with a low dose and increase based on TSH
◦ Check a pulse before giving (hold if >100)
◦ This drug requires an empty stomach (acidic pH)
◦ Give first thing in the morning
Do not give with cations (zinc, iron, calcium, magnesium), these can bind to ? This means supplements and foods-such as milk, yogurt, etc. a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
Levothyroxine
Do not administer with bile acid
sequestrants (cholestyramine) separate by ?
hours- these will also bind to the drug
Do not administer with bile acid
sequestrants (cholestyramine) separate by 4
hours- these will also bind to the drug
Do not administer with bile acid sequestrants (cholestyramine) a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
Danger with other sympathomimetic drugs
a. Levothyroxine
b. Liothyronine, desiccated thyroid
c. Methimazole
a. Levothyroxine
Can increase the effects of warfarin
a. Levothyroxine
b. Liothyronine, desiccated thyroid
c. Methimazole
a. Levothyroxine
Educate patients that it will take several weeks to notice improvement (we generally
check levels around ? weeks after starting)
Educate patients that it will take several weeks to notice improvement (we generally
check levels around 4-6 weeks after starting)
Used when someone has an issue converting to T4 to T3
• Used when someone is not sufficiently controlled with T4
a. Levothyroxine
b. Liothyronine, desiccated thyroid
c. Methimazole
Liothyronine
Used for hypothyroidism
• Some patients prefer a more “Natural” Route
• Not recommended by Leading Associations
a. Levothyroxine
b. Liothyronine, desiccated thyroid
c. Methimazole
desiccated thyroid
Synthetic T3
b. Liothyronine, desiccated thyroid
Liothyronine
Ground down animal thyroid (pig)
◦ Ratio of 4.2:1 of T4 to T3 (does not match human ratio)
b. Liothyronine, desiccated thyroid
desiccated thyroid
H eat intolerance E xcitement (insomnia) A ngina R estless T achycardia/Tremor a. Levothyroxine b. Liothyronine, desiccated thyroid c. Methimazole
a. Levothyroxine
b. Liothyronine, desiccated thyroid
Graves’ disease
HYPERTHYROIDISM or HYPOTHYROIDISM
HYPERTHYROIDISM
Thyroid storm (induced by stress or infection) ◦ Severe and potentially life threatening
HYPERTHYROIDISM or HYPOTHYROIDISM
HYPERTHYROIDISM
USED TO TREAT • Hyperthyroidism • Graves Disease • Thyroid Storm c. Methimazole + Propylthiouracil (PTU) e. Potassium iodide f. Radioactive Iodine
c. Methimazole + Propylthiouracil (PTU)
◦ Prevents coupling of iodinated tyrosine’s in the
thyroid
c. Methimazole + Propylthiouracil (PTU)
Methimazole
◦ Prevents coupling of iodinated tyrosine’s , but also prevents peripheral conversion of T4 to T3 c. Methimazole + Propylthiouracil (PTU)
Propylthiouracil (PTU)
ADVERSE EFFECTS: ◦ Liver and Bone Marrow Suppression c. Methimazole + Propylthiouracil (PTU) e. Potassium iodide f. Radioactive Iodine
c. Methimazole + Propylthiouracil (PTU
- BOXED WARNING- hepatotoxicity
◦ monitor for s/s, routine LFT monitor doesn’t seem to help
◦ has resulted in multiple liver transplants and death
c. Methimazole + Propylthiouracil (PTU)
e. Potassium iodide
f. Radioactive Iodine
Propylthiouracil (PTU)
Avoid eating foods high in iodine (seafood, soy sauce, tofu, and iodized salt) c. Methimazole + Propylthiouracil (PTU) e. Potassium iodide f. Radioactive Iodine
c. Methimazole + Propylthiouracil (PTU)
Monitor for Liver & Bone Marrow Suppression:
◦ leukopenia (manifested as fever, sore throat, lesions)
◦ Don’t forget other bone marrow lineages
c. Methimazole + Propylthiouracil (PTU)
e. Potassium iodide
f. Radioactive Iodine
c. Methimazole + Propylthiouracil (PTU)
works by destroying the thyroid gland
c. Methimazole + Propylthiouracil (PTU)
e. Potassium iodide
f. Radioactive Iodine
f. Radioactive Iodine
USED TO TREAT Thyroid Tumor ◦ Goiter e. Potassium iodide f. Radioactive Iodine
f. Radioactive Iodine
Sometimes used as marker for procedures
(Diagnostic Agent)
e. Potassium iodide
f. Radioactive Iodine
f. Radioactive Iodine
USED TO TREAT
Following radioactive iodine exposure, potassium
iodide blocks the uptake of radioactive iodine by the
thyroid, reducing the risk of thyroid cancer and thyroid
destruction
e. Potassium iodide
f. Radioactive Iodine
e. Potassium iodide
◦ Nuclear Medicine testing- if target is other than
the thyroid
e. Potassium iodide
f. Radioactive Iodine
e. Potassium iodide