Thyroid

Question 1

Medications that can affect TSH secretion

Answer 1

Decrease TSH
-dopamine, high dose glucocorticoids, octreotide (GOD)

Increase TSH
-dopamine antagonists, amiodarone (ADD)

GOD ADDs to your life, start low to high

Question 2

Interpreting Thyroid Function Tests

Answer 2

Question 3

Hypothyroidism SX

Answer 3

• weight GAIN
• low energy
• depression
• COLD intolerance
• constipation
• bradycardia
• dry skin

most common: hashimoto’s

Question 4

Drug-induced Hypothyroidism

Answer 4

• Amiodarone
• Carbamazepine
• Interferons
• Lithium
• Tyrosine kinase inhibitors (sunitinib, sorafenib)

CAL IT!

Question 5

Hypothyroidism TX options

Answer 5

• T4 replacement: levothyroxine (synthetic, man made)
• T3 replacement: liothyronine (Cytomel)
• T3/T4 combination: Armour Thyroid (FROM PIGS, DONT USE IF PORK ALLERGY)

Question 6

Levothyroxine (Synthroid): dose, CI, warning, how to take

Answer 6

Drug of choice

-1.6 ug/kg/day (elderly need 20-25% less, >50 yo)
-cardiac diseases: 12.5-25 ug daily

-Warning: NOT for obesity or weight loss, toxicity

-CI: adrenal insufficiency, glucocorticoid therapy initiation

-with water, same time each day, 30-60 min before bfast or 3 hr after din, don’t crush/chew

-brand name recommended (or same generic preparation)

Question 7

Levothyroxine Titration

Answer 7

• In increments of 12.5-25 ug
• Titrate every 4-6 weeks until TSH is normal, then 4-6 months, then yearly

Question 8

Check Free T4 for: selected patients

Answer 8

• poor absorption
• Pregnancy
• central hypothyroidism (defect in pituitary production of TSH)

T4 for PPP

Question 9

Liothyronine (Cytomel)

Answer 9

• 25 mcg PO daily
• Titrate in 12.5-25 mcg increments
• Maintenance: 25-75 mcg PO daily
• Titrate Q 1-2 weeks

Question 10

Armour Thyroid (desiccated thyroid)

Answer 10

**1 grain = 60 mg = 100 mcg levothyroxine++

• Initial: 15-30 mg PO daily (15 mg in CAD patients)
• Titrate by 15 mg q2-3 weeks
• Maintenance: 60-120 mg/day

SE: increase rate of hypersensitivity

Question 11

Medications to separate by 4 hours

Answer 11

• Medications containing polyvalent cations (iron, calcium, aluminum)
• Bile-acid sequestrants
• Sucralfate
• Orlistat
• Sevelamer
• Sodium polystyrene sulfonate

MOB triple SSS

Question 12

Medications to separate by 3 hours

Answer 12

Patiromer

pat is 3

Question 13

Medications to separate by 2 hours

Answer 13

Lanthanum

Question 14

Effect of hypothyroidism on medications

Answer 14

Digoxin: decrease doses achieve therapeutic levels

Warfarin: increase doses needed due to slowed catabolism of clotting

BUT IF YOU FIX IT OPPOSITE

Question 15

Hyperthyroidism SX

Answer 15

• weight LOSS
• tachycardia, palp
• insomnia
• nervous, anxiety
• HEAT intolerance
• diarrhea
• tremor, weak muscles
• onyvholysis (nails), bulging eyes, goiter**

most common cause is grave’s

Question 16

Hyperthyroidism TX

Answer 16

Thioamide: PTU and MMI

Radioactive iodine

Surgery

Question 17

Propylthiouracil (PTU), Methimazole (MMI) MOAs

Answer 17

-Block synthesis of thyroid hormone (BOTH)

-PTU (ONLY) blocks peripheral conversion of T4 to T3

Question 18

PTU and MMI dosing

Answer 18

MMI
-Initial: 15-40 mg/day PO 1-2x/day
-Main: 5-15 mg/day

PTU
-Initial: 50-150 mg PO TID
-Main: 50 mg PO BID-TID

Question 19

PTU/MMI AE

Answer 19

Rash
Pancreatitis
*Agranulocytosis
Arthralgias and lupus-like syndrome
*Vasculitis
*GI effects
*Hepatotoxicity: children are more susceptible to hepatotoxic reactions from PTU than are adults

GAAV the RPH

Question 20

PTU/MMI Monitoring

Answer 20

-FT4 and total T3 should be obtained 2–6 weeks after initiation
-Once euthyroid, dose of MMI can be decreased by 30%–50%, testing repeated in 4–6 wk
-Then test every 2-3 mo, if longterm >18mo then every 6 mo
-If med is primary therapy, should be continued for 12–18 mo, then d/c if TSH and TRAb levels are normal at that time
-AST/ALT/Alk Phos/WBC/ANC labs

CBC and LFTs

Question 21

Adjunctive therapies: Beta Blockers

Answer 21

-Blocks T4 to T3

*Atenolol: 25-50 mg a day
*Propranolol: 20-40 mg a day

SE: hypotension, bradycardia, av block (BP HR EKG)

Question 22

Adjunctive therapies: Iodides

Answer 22

• dilute in full glass of liquid
• take with food or milk

SE: HS rxn, salivary gland swelling, metallic taste or mouth/throat irritation, sore gums/teeth, diarrhea

SMD HP (contra: preg)

CI: iodine HS, pregnancy/BF

10 days prior to surgery OR 3-7 days after radiotherapy

Question 23

Myxedema Coma TX

Answer 23

T4 200-400 ug IV a
AND
hydrocortisone 100 mg IV q8h
AND
supportive, treat underlying disorder

Question 24

Thyroid Storm TX

Answer 24

-103+ fever, sweat, tachy, A fib, dehydration, delirium

PTU preferred, 500-1000 mg load then 250 mg q4h
+ BB + iodine + steroid

Question 25

Pregnancy

Answer 25

HYPO -increased levothyroxine requirement during and months post partum HYPER -PTU during first tri -MMI for rest of pregnancy

Question 26

TSH Normal Ranges

Answer 26

0.27-4.2

Question 27

T4 and free T4 Normal Ranges

Answer 27

T4: 4.5-10.9 Free T4: 0.93-1.7

Question 28

T3 Total

Answer 28

0.8-2

Question 29

Colors of Levothyroxine/Synthroid/Levoxyl

Answer 29

Orangutans will vomit on you right before they become large proud giants -Orange: 25 mcg -White: 50 -Violet: 75 -Olive: 88 -Yellow: 100 -Rose: 112 -Brown: 125 -Teal: 137 -Blue: 150 -Lilac: 175 -Pink: 200 -Green: 300