Term
| How is warfarin affected by thyroid disorders? |
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Definition
- Clotting factors increased in hypothyroidism/decreased clearance
- Clotting factors decreased in hyperthyroidism/increased clearance
- Treatment of hyperthyroidism, BMR slows down, clotting factors increase b/c not cleared as fast -- warfarin requirements increased.
- When hypothyroidism is treated, BMR increases, clotting factors cleared faster, warfarin more effective and requirements decreased. |
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Term
| How is hyperthyroidism treated? |
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Definition
- PTU/MMI
- Thyroidectomy via radioactive iodine or surgery
- Propranolol slows conversion of T4 to T3 |
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Term
Which drugs are Thioureylenes/Thioamides?
How are they used? |
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Definition
Propylthiouracil/PTU - can cause liver damage, preferred in pregnancy
Methimazole/MMI - used most often due to QD dosing
Monitor TFT, LFTs, CBC
Take w/ food, report jaundice
Interact w/ warfarin, can cause Agranulocytosis
50% remission rate |
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Term
| How are iodide drugs used? |
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Definition
SSKI, Lugol's solution
Saturates transport system, inhibiting organification of iodine.
Use before surgery or after RAI
Side effects rare, some numbness or rash
Monitor TFTs, K+. Take with meals, mix w/ water or juice. Stop if rash occurs. |
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Term
| What are advantages and disadvantages of oral iodide? |
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Definition
Advantages: rapid, good for after surgery, abates thyroid storm
Disadvantages: Not for long term, can't use RAI for several weeks after, delays onset of MMI or PTU |
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Term
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Definition
60% euthyroid within 6 months to 1 year
40% require additional RAI
AEs: pain, dysphagia, cannot use in pregnancy
Advantage: no surgery, selective for thyroid
Disadv: thyroid toxicosis, can't use in pregnancy or lactating |
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Term
| What is the standard of care for thyroid brand supplements? |
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Definition
| Once started on a brand, stay with that brand. Otherwise it doesn't matter. |
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Term
| How is levothyroxine used? |
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Definition
Starting dose 50 mcg (25 if CAD), titrate to 100-150 mcg. 3-4 week onset.
AE: s/s of hyperthyroidism.
Separate from cations, take on an empty stomach.
Interacts w/ cations & sequestrants, soy, 3A4 inducers, warfarin |
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Term
| How is Liothyronine used? |
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Definition
T3 - faster onset (2-3) days.
Same onset and reactions as other thyroid drugs.
MORE cardiac side effects, difficult to monitor |
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Term
| What other drugs are used to treat hypothyroidism? |
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Definition
Liotrix - T4:T3 in a 4:1 ratio
Armour thyroid - dessicated pig thyroid gland. Can be antigenic |
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