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Flashcards in 30. Thyroid Disorders Deck (32):
1

A patient is admitted and was taking levothyroxine 100 mcg daily at home. She is NPO and provider would like the levothyroxine continued IV. What is the most appropriate dose for the pharmacist to dispense?

A. 112 mcg
B. 50 mcg
C. 200 mcg
D. 100 mg
E. 75 mcg
 

E. The recommended IV to PO ratio in the most recent guidelines is 0.75 to 1.

IV:PO ratio is 0.75:1, IV form not stable and should be given once prepared

2

Which of the following statements concerning treatment of hyperthyroidism during pregnancy is correct?

A. Methimazole is used in the first trimester of pregnancy.
B. PTU is used in the 2nd and 3rd trimesters.
C. Hyperthyroidism should not be treated during pregnancy.
D. The treatment of choice for hyperthyroidism in pregnancy is radioactive iodine.
E. Women can commonly get hyperthyroidism during the reproductive years; most cases are in females in their 30's and 40's.
 

E. PTU is used in the first trimester of pregnancy, but methimazole is used in the 2nd and 3rd trimesters due to the higher risk of liver toxicity from PTU.

Thionamides: inhibit synthesis of thyroid hormones by blocking oxidation of iodine in the thyroid gland; PTU also inhibits peripheral conversion of T4 to T3

Boxed warning: severe liver injury and liver failure (with PTU)

SE: GI upset, hepatitis, agranulocytosis (rare), pregnancy (D)

Propylthiouracil (PTU) is preferred under 2 scenarios: thyroid storm and 1st trimester of pregnancy. Otherwise use methimazole (Tapazole) in 2nd and 3rd trimester because less hepatoxicity compared to PTU

Take with food to minimize GI upset

3

Select the correct statements concerning levothyroxine: (Select ALL that apply.)

A. It contains T3.
B. It is the preferred agent for treating hypothyroidism.
C. It is derived from dessicated porcine gland.
D. It contains T4
E. It will lower the TSH
 

B, D, E. Levothyroxine is synthetic T4, not T3. The body converts T4 to T3. It is the preferred agent and matches human T4.

Tx: Levothyroxine (Synthroid, Levoxyl) is top drug

For adults <50 years of age: 1.6mcg/kg/day (IBW) – full replacement dose

Elderly, mild disease, or co-morbidities: 25-50mcg/day – partial replacement dose. We are concerned about cardiovascular problems and drug interactions

If known CVD: 12.5-25mcg/day

Boxed warning: not to be used for weight loss

SE: none, Pregnancy (A), lots of DDI (polyvalent cation, iron, orlistat, svelamer, other-separate by 4 hours; lanthanum separate by 2 hours), beta-blockers, amiodarone, steroid, PTU can decrease conversion of T4 to T3

Monitor: TSH (rarely free T4) and symptoms every 4-6 weeks until normal, then 4-6 months later, then yearly. Monitor as patient ages, may need to decrease dose; over dosing lead to Afib and fractures

IV:PO ratio is 0.75:1, IV form not stable and should be given once prepared

Take levothyroxine with water 60 minutes before breakfast or at bedtime, 3 hours after the last meal. Separate from bisphosphonates

4

A patient gave the pharmacist a prescription for Cytomel 25 micrograms once daily #30. Which of the following is an appropriate generic substitution for Cytomel?

A. Methimazole
B. Levothyroxine
C. Liothyronine
D. Thyroid USP
E. Propylthiouracil
 

C. The generic name of Cytomel is liothyronine.

methimazole (Tapazole)

levothyroxine (Synthroid, Levoxyl)

thyroid USP (Armour Thyroid, Nature-Throid)

5

Alison has been prescribed propylthiouracil. What common side effect might she experience?

A. Bradycardia
B. GI upset
C. Hypotension
D. Diarrhea
E. Hyperglycemia
 

B. Both methimazole and PTU can cause rash, and GI side effects (nausea, vomiting). With both drugs, the liver must be monitored; PTU has a boxed warning for hepatotoxicity.

Thionamides: inhibit synthesis of thyroid hormones by blocking oxidation of iodine in the thyroid gland; PTU also inhibits peripheral conversion of T4 to T3

Boxed warning: severe liver injury and liver failure (with PTU)

SE: GI upset, hepatitis, agranulocytosis (rare), pregnancy (D)

Propylthiouracil (PTU) is preferred under 2 scenarios: thyroid storm and 1st trimester of pregnancy. Otherwise use methimazole (Tapazole) in 2nd and 3rd trimester because less hepatoxicity compared to PTU

Take with food to minimize GI upset

6

Chief Complaint:  "I have a fever and I can't sleep"
History of Present Illness:  JS is a 35 y/o male being treated for a severe MRSA skin infection.  He presents to the clinic complaining of fever, nausea, increased insomnia, and "feeling like I'm going crazy".  He appears very agitated and presents with hand tremor and moist skin.  He recently picked up a second job, working 60 hours a week, and attributes his worsening insomnia to stress.
Past Medical History: Insomnia (x 3 years), atrial fibrillation, MRSA skin infection diagnosed 10 days ago   
Medications: Melatonin 5 mg QHS, warfarin 5mg daily, Zyvox 600 mg PO BID, MVI daily    
Pertinent Social History: Alcohol 2-3x/week to help him sleep    
Vitals: 
Height: 5'10"  Weight: 141 lbs 
BP: 140/96 mmHg  HR: 105 BPM  RR: 22 BPM  Temp: 104ºF  Pain: 2/10    
Labs: 
Na (mEq/L) = 141 (135 - 145)                       
K (mEq/L) = 4.2 (3.5 - 5)                             
Cl (mEq/L) = 100 (95 - 103)                         
HCO3 (mEq/L) = 28 (24 - 30)                       
BUN (mg/dL) = 18 (7 - 20)                           
SCr (mg/dL) = 0.9 (0.6 - 1.3)                 
Glucose (mg/dL) = 110 (100 - 125) 
Mg (mEq/L) = 1.9 (1.3 - 2.1) 
PO4 (mg/dL) = 4.3 (2.3 - 4.7) 
Ca (mg/dL) = 9.5 (8.5 - 10.5) 
TSH (mIU/L) = 0.1 (0.3-3.0)  
INR = 2.9 (2-3)   
Question:
What is JS experiencing? 

A. New onset hypothyroidism
B. Thyroid storm
C. Panic attack
D. Myxedema coma
E. Hypertensive crisis
 

B. Based on the patient’s lab values and clinical symptoms, he is experiencing thyroid storm. Thyroid storm is a life-threatening medical emergency characterized by decompensated hyperthyroidism that can be precipitated by infection, trauma, surgery, radio-active iodine treatment or non-adherence to antithyroid medication.

Thyroid Storm

Medical emergency!

S/sx: fever >103'F, tachycardia, tachypnea, profound sweating, dehydration, delirium, psychosis, coma

Tx: PTU (900-1200mg PO divided Q4-6H), iodide therapy (SSKI, Lugol's solution Q8H), beta-blocker (to control tachycardia, palpitations, propranolol 40-80mg Q6H), steroids, aggressive cooling with APAP and cooling blankets, supportive care.

7

Connie uses warfarin for atrial fibrillation. Connie has just left the hospital with several new medications: levothyroxine, diltiazem and amiodarone. Select the correct statement/s: (Select ALL that apply.)

A. The levothyroxine can make the INR become supratherapeutic.
B. The diltiazem can make the levothyroxine subtherapeutic.
C. The patient will be at increased risk for forming a deep vein thrombosis.
D. The amiodarone can make the INR become supratherapeutic.
E. The diltiazem can make the warfarin subtherapeutic.
 

A, D. Levothyroxine can increase the INR and a patient stable on warfarin will require monitoring of the INR when levothyroxine is added. Amiodarone causes a large increase in the INR and the clinician should decrease the warfarin dose when amiodarone is added to a patient with a stable INR. Both drugs put the patient at increased risk for bleeding, not clotting.

Remember that levothyroxine increase metabolism and hence warfarin gets metabolized to active form faster leading to increased INR.

Amiodarone is a CYP inhibitor and so more warfarin.

8

Alison has been prescribed propylthiouracil, which should be reserved for patients who cannot use other options due to the risk of this adverse reaction:

A. Fatal skin rash
B. Liver damage
C. Trouble breathing/laryngoedema
D. Renal failure
E. Cardiotoxicity
 

B. PTU has a boxed warning for severe liver injury, which can come on suddenly, even after long-term use.

9

Chief Complaint:  "I have no energy"
History of Present Illness:  KB is a 32 y/o female who comes into the outpatient clinic complaining of low energy, recent weight gain of 15 pounds, foggy memory, and feeling cold even though it is sunny outside. She is diagnosed with hypothyroidism and started on levothyroxine. 
Past Medical History: Allergic rhinitis, GERD, Hypothyroidism 
Current Medications: Cetirizine 10 mg PRN, Mylanta 20 mL Q6H, Tylenol 325 mg Q4-6H PRN, Omega-3 fatty acid 1 gram daily, MVI daily    
Vitals: 
Height: 5'7"  Weight: 138 lbs 
BP: 129/80 mmHg  HR: 85 BPM  RR: 20 BPM  Temp: 98.6ºF  Pain: 1/10    
3/10/14 Labs: 
Na (mEq/L) = 141 (135 - 145)                       
K (mEq/L) = 4.2 (3.5 - 5)                             
Cl (mEq/L) = 100 (95 - 103)                         
HCO3 (mEq/L) = 28 (24 - 30)                       
BUN (mg/dL) = 18 (7 - 20)                           
SCr (mg/dL) = 0.9 (0.6 - 1.3)                 
Glucose (mg/dL) = 110 (100 - 125) 
Mg (mEq/L) = 1.9 (1.3 - 2.1) 
PO4 (mg/dL) = 4.4 (2.3 - 4.7) 
Ca (mg/dL) = 9.5 (8.5 - 10.5) 
TSH (mIU/L) = 32 (0.3-3.0) 
Free T4 (mg/dL) = 0.3 (0.9-2.3) 
hCG-    
Plan:
Hypothyroidism.  Start levothyroxine 75 mcg daily.  Follow-up visit on 4/14/14.
4/14/14 Labs: 
Na (mEq/L) = 143 (135 - 145)                       
K (mEq/L) = 4.1 (3.5 - 5)                             
Cl (mEq/L) = 102 (95 - 103)                         
HCO3 (mEq/L) = 26 (24 - 30)                       
BUN (mg/dL) = 15 (7 - 20)                           
SCr (mg/dL) = 0.8 (0.6 - 1.3)                
Glucose (mg/dL) = 15 (100 - 125) 
Mg (mEq/L) = 1.8 (1.3 - 2.1) 
PO4 (mg/dL) = 4.1 (2.3 - 4.7) 
Ca (mg/dL) = 9.7 (8.5 - 10.5) 
TSH (mIU/L) = 4.7 (0.3-3.0) 
hCG+    
Question:
On KB's 4/14/14 visit, what changes should be made to her drug regimen?

A. The levothyroxine dose should be increased
B. The levothyroxine dose should be decreased
C. The levothyroxine should be changed to Thyrolar
D. Thyroid replacement therapy should be discontinued
E. No changes should be made

A. KB's serum TSH is not yet in the reference range. TSH and clinical symptoms should be checked every 4-6 weeks until they are normal. KB also has a positive pregnancy test on this visit. Pregnant women need higher levothyroxine doses throughout their pregnancies.

Can also calculate full replacement dose 1.6mg/kg/day x IBW = 1.6 x 61.59 = 98.5mcg/day

Tx: Levothyroxine (Synthroid, Levoxyl) is top drug

For adults <50 years of age: 1.6mcg/kg/day (IBW) – full replacement dose

Elderly, mild disease, or co-morbidities: 25-50mcg/day – partial replacement dose. We are concerned about cardiovascular problems and drug interactions

If known CVD: 12.5-25mcg/day

Boxed warning: not to be used for weight loss

SE: none, Pregnancy (A), lots of DDI (polyvalent cation, iron, orlistat, svelamer, other-separate by 4 hours; lanthanum separate by 2 hours), beta-blockers, amiodarone, steroid, PTU can decrease conversion of T4 to T3

Monitor: TSH (rarely free T4) and symptoms every 4-6 weeks until normal, then 4-6 months later, then yearly. Monitor as patient ages, may need to decrease dose; over dosing lead to Afib and fractures

IV:PO ratio is 0.75:1, IV form not stable and should be given once prepared

Take levothyroxine with water 60 minutes before breakfast or at bedtime, 3 hours after the last meal. Separate from bisphosphonates

10

Which of the following statements concerning thyroid function are correct? (Select ALL that apply.)

A. In a normally functioning system, thyroid-stimulating hormone (TSH) stimulates the secretion of thyroxine (T4) and, minimally, triiodothyronine (T3).
B. Total daily T3 production results from the peripheral conversion of T4 to T3 (roughly 80%).
C. T3 is 3-4 times as potent as T4.
D. T4 is 3-4 times as potent as T3.
E. Elevations in T4 inhibit the secretion of TSH, and a negative feedback loop is created.
 

A, B, C, E. T3 is much more potent than T4. T4 inhibits the secretion of TSH via negative feedback.

11

A patient has been prescribed Synthroid. She wishes to use a generic. Choose the correct statement/s concerning generic options for levothyroxine brand formulations: (Select ALL that apply.)

A. The correct source to check for therapeutic (AB-rated) equivalents is the red book.
B. All generics of levothyroxine are AB related to each of the available brand formulations.
C. If a patient changes manufacturers, it is prudent to monitor for symptoms of hypo or hyperthyroidism as the dosage may vary slightly.
D. Patients should be told to use brand name only.
E. Levothyroxine has a narrow therapeutic index.
 

C, E. The correct source to check for therapeutic (AB-rated) equivalents is the orange book. Levothyroxine comes in many dosages and various brands. One manufacturer's dosage may not be AB-rated to the same dosage produced by a different manufacturer. If a dosage or manufacturer is changed, symptoms should be monitored. Patients should be told to try to stay with the same formulation. The pharmacist should dispense only alternatives that are AB-rated to the formulation the patient has been using.

12

Select the correct pathway that describes thyroid function:

A. Thyroid-stimulating hormone (TSH) stimulates the secretion of thyroxine (T4).
B. Thyroid-stimulating hormone (TSH) accounts for the majority of triiodothyronine (T3) production.
C. T3 is converted to T4.
D. Thyroid-stimulating hormone (TSH) is stimulated by elevations of T4.
E. In patients with hypothyroidism, T4 cannot be converted into T3.
 

A. In a normally functioning system, thyroid-stimulating hormone (TSH) stimulates the secretion of thyroxine (T4) and, minimally, triiodothyronine (T3). Total daily T3 production results from the peripheral conversion of T4 to T3 (roughly 80%).

13

Cheri believes she may be pregnant. She goes to see her doctor who orders various tests, including TSH and FT4. Cheri is found to have a high TSH, low FT4 and is hCG+. She is prescribed a prenatal vitamin and levothyroxine. Choose the correct statements concerning the levothyroxine pregnancy category.

A. Levothyroxine is pregnancy category A
B. Levothyroxine is pregnancy category B
C. Levothyroxine is pregnancy category C
D. Levothyroxine is pregnancy category D
E. Levothyroxine is pregnancy category X
 

A. When preparing for pregnancy or at the initial visit the physician will check thyroid function. If the woman is hypothyroid and it is not corrected with thyroid hormone replacement, the child will suffer neurological damage. If a person becomes pregnant while using levothyroxine, they must continue to use it and the dose will be increased. Levothyroxine is pregnancy category A.

14

A 40 year-old, female patient has been prescribed levothyroxine 50 mcg once daily. Choose the correct counseling statement:

A. Take this medicine with breakfast.
B. Take this medicine with lunch.
C. Take this medicine an hour before breakfast, on an empty stomach.
D. Take this medicine with dinner.
E. Take this medicine at bedtime, with a light snack.
 

C. Levothyroxine is taken in the morning, preferably on an empty stomach, an hour before breakfast. This optimizes the amount of drug absorbed. However, if the patient has been taking it with breakfast, do not change it. They may have had the level adjusted to the way they are using the medicine. Levothyroxine will cause insomnia if taken later in the day.

Tx: Levothyroxine (Synthroid, Levoxyl) is top drug

For adults <50 years of age: 1.6mcg/kg/day (IBW) – full replacement dose

Elderly, mild disease, or co-morbidities: 25-50mcg/day – partial replacement dose. We are concerned about cardiovascular problems and drug interactions

If known CVD: 12.5-25mcg/day

Boxed warning: not to be used for weight loss

SE: none, Pregnancy (A), lots of DDI (polyvalent cation, iron, orlistat, svelamer, other-separate by 4 hours; lanthanum separate by 2 hours), beta-blockers, amiodarone, steroid, PTU can decrease conversion of T4 to T3

Monitor: TSH (rarely free T4) and symptoms every 4-6 weeks until normal, then 4-6 months later, then yearly. Monitor as patient ages, may need to decrease dose; over dosing lead to Afib and fractures

IV:PO ratio is 0.75:1, IV form not stable and should be given once prepared

Take levothyroxine with water 60 minutes before breakfast or at bedtime, 3 hours after the last meal. Separate from bisphosphonates

15

What is the most common cause of hypothyroidism?

A. Lithium
B. Amiodarone
C. Hashimoto's disease
D. Graves' disease
E. Radiation therapy
 

C. The most common cause of hypothyroidism is Hashimoto's disease, an autoimmune condition in which a patient's antibodies attack their own thyroid gland. Drugs can also cause hypothyroidism, most notably lithium and amiodarone-both of which require monitoring of thyroid function tests.

Graves' disease is most common cause (autoimmune) of hyperthyroidism. Remember Graves' is hyperthyroid because it can lead to thyroid storm which is fatal and patients may end up in the "grave".  This means the Hashimoto must be hypothyroidism.

16

Alison is a 33 year-old female who has been diagnosed with hyperthyroidism. She is waiting for an appointment to see an endocrinologist. In the meantime, she has been given a prescription for propylthiouracil and propranolol. Choose the correct statement/s: (Select ALL that apply.)

A. The propylthiouracil increases the production of T3.
B. The propranolol will help reduce hyperthyroid symptoms.
C. The propylthiouracil increases the production of T4.
D. The propylthiouracil inhibits thyroid hormone synthesis.
E. The propranolol increases the production of TSH.
 

B, D. Beta blockers, such as propranolol, can block the tachycardia and trembling. PTU and methimazole inhibit thyroid hormone synthesis.

17

A patient has been diagnosed with hyperthyroidism. The following signs and symptoms would be expected to be present: (Select ALL that apply.)

A. High TSH
B. Low FT4
C. Agitation, irritability and tachycardia
D. Diarrhea
E. Depression
 

C, D. TSH, FT4 and clinical symptoms are used to diagnose thyroid disorders. If the patient is hyperthyroid, the TSH will be low and the FT4 will be high. The opposite is true in hypothyroidism (high TSH and low FT4).

18

Chief Complaint:  "I have a fever and I can't sleep"
History of Present Illness:  JS is a 35 y/o male being treated for a severe MRSA skin infection.  He presents to the clinic complaining of fever, nausea, increased insomnia, and "feeling like I'm going crazy".  He appears very agitated and presents with hand tremor and moist skin.  He recently picked up a second job, working 60 hours a week, and attributes his worsening insomnia to stress.
Past Medical History: Insomnia (x 3 years), atrial fibrillation, MRSA skin infection diagnosed 10 days ago   
Medications: Melatonin 5 mg QHS, warfarin 5mg daily, Zyvox 600 mg PO BID, MVI daily    
Pertinent Social History: Alcohol 2-3x/week to help him sleep    
Vitals: 
Height: 5'10"  Weight: 141 lbs 
BP: 140/96 mmHg  HR: 105 BPM  RR: 22 BPM  Temp: 104ºF  Pain: 2/10    
Labs: 
Na (mEq/L) = 141 (135 - 145)                       
K (mEq/L) = 4.2 (3.5 - 5)                             
Cl (mEq/L) = 100 (95 - 103)                         
HCO3 (mEq/L) = 28 (24 - 30)                       
BUN (mg/dL) = 18 (7 - 20)                           
SCr (mg/dL) = 0.9 (0.6 - 1.3)                 
Glucose (mg/dL) = 110 (100 - 125) 
Mg (mEq/L) = 1.9 (1.3 - 2.1) 
PO4 (mg/dL) = 4.3 (2.3 - 4.7) 
Ca (mg/dL) = 9.5 (8.5 - 10.5) 
TSH (mIU/L) = 0.1 (0.3-3.0)  
INR = 2.9 (2-3)   
Question:
JS is sent to the hospital for treatment.  An order for propylthiouracil is written. What other medications should be initiated? 

A. Potassium chloride, acetaminophen, propranolol and dexamethasone
B. SSKI, propranolol, dexamethasone and acetaminophen
C. Levothyroxine, SSKI, magnesium and aspirin
D. Liotrix, acetaminophen, Lugol’s solution and dexamethasone
E. Potassium chloride, ThyroShield, and metoprolol
 

B. In addition to PTU, patients with thyroid storm should be treated with SSKI or Lugol's solution, a beta blocker, a corticosteroid, and acetaminophen.

Thyroid Storm

Medical emergency!

S/sx: fever >103'F, tachycardia, tachypnea, profound sweating, dehydration, delirium, psychosis, coma

Tx: PTU (900-1200mg PO divided Q4-6H), iodide therapy (SSKI, Lugol's solution Q8H), beta-blocker (to control tachycardia, palpitations, propranolol 40-80mg Q6H), steroids, aggressive cooling with APAP and cooling blankets, supportive care.

19

Jane is a 78 year-old female with heart failure and history of MI. She has just been diagnosed with hypothyroidism. Jane is five feet tall and weighs 103 pounds. She is going to begin levothyroxine therapy. What is an appropriate starting dose in this patient?

A. 12.5-25 mcg/day
B. 25-50 mcg/day
C. 50-75 mcg/day
D. 75-100 mcg/day
E. 100-150 mcg/day
 

A. Patients with known CAD are started at 12.5-25 mcg/day. The patient returns in 4-6 weeks and the dose is adjusted until the TSH is normalized and symptoms have resolved. The average maintenance dose of levothyroxine for most adult patients is 100-150 mcg/day. Older patients often require less.

Tx: Levothyroxine (Synthroid, Levoxyl) is top drug

For adults <50 years of age: 1.6mcg/kg/day (IBW) – full replacement dose

Elderly, mild disease, or co-morbidities: 25-50mcg/day (or 0.5mcg/kg/day) – partial replacement dose. We are concerned about cardiovascular problems and drug interactions

If known CVD: 12.5-25mcg/day

20

Which of the following statements concerning treatment of hyperthyroidism are correct? (Select ALL that apply.)

A. Radioactive iodine (RAI-131) is the treatment of choice in Grave's disease.
B. Beta blockers are often used initially to control symptoms such as palpitations and racing heart beat.
C. Methimazole is preferred in thyroid storm.
D. Initially, higher doses of drugs are used to control symptoms; afterwards the dose of the drugs is typically decreased to prevent over-treatment, and consequently, hypothyroidism.
E. Both propylthiouracil and methimazole cause GI upset, including nausea, and can damage the liver.
 

A, B, D, E. Propylthiouracil is preferred in thyroid storm.

21

What is the most common cause of hyperthyroidism?

A. Lithium
B. Amiodarone
C. Hashimoto's disease
D. Graves' disease
E. Radiation therapy
 

D. The most common cause is Graves' disease, which tends to occur in females in the 30's and 40's. Graves' disease is an autoimmune disorder (like Hashimoto's) but instead of destroying the gland, the antibodies stimulate the thyroid to produce too much T4.

Graves' disease is most common cause (autoimmune) of hyperthyroidism. Remember Graves' is hyperthyroid because it can lead to thyroid storm which is fatal and patients may end up in the "grave".  This means the Hashimoto must be hypothyroidism.

22

Chief Complaint:  "I have a fever and I can't sleep"
History of Present Illness:  JS is a 35 y/o male being treated for a severe MRSA skin infection.  He presents to the clinic complaining of fever, nausea, increased insomnia, and "feeling like I'm going crazy".  He appears very agitated and presents with hand tremor and moist skin.  He recently picked up a second job, working 60 hours a week, and attributes his worsening insomnia to stress.
Past Medical History: Insomnia (x 3 years), atrial fibrillation, MRSA skin infection diagnosed 10 days ago   
Medications: Melatonin 5 mg QHS, warfarin 5mg daily, Zyvox 600 mg PO BID, MVI daily    
Pertinent Social History: Alcohol 2-3x/week to help him sleep    
Vitals: 
Height: 5'10"  Weight: 141 lbs 
BP: 140/96 mmHg  HR: 105 BPM  RR: 22 BPM  Temp: 104ºF  Pain: 2/10    
Labs: 
Na (mEq/L) = 141 (135 - 145)                       
K (mEq/L) = 4.2 (3.5 - 5)                             
Cl (mEq/L) = 100 (95 - 103)                         
HCO3 (mEq/L) = 28 (24 - 30)                       
BUN (mg/dL) = 18 (7 - 20)                           
SCr (mg/dL) = 0.9 (0.6 - 1.3)                 
Glucose (mg/dL) = 110 (100 - 125) 
Mg (mEq/L) = 1.9 (1.3 - 2.1) 
PO4 (mg/dL) = 4.3 (2.3 - 4.7) 
Ca (mg/dL) = 9.5 (8.5 - 10.5) 
TSH (mIU/L) = 0.1 (0.3-3.0)  
INR = 2.9 (2-3)   
Question:
JS is sent to the hospital for treatment.  An order for propylthiouracil (PTU) is written. Which of the following is correct regarding drug interactions with PTU and JS's current medications?

A. PTU may increase the anticoagulant effect of warfarin.
B. PTU may decrease the anticoagulant effect of warfarin.
C. PTU is contraindicated with Zyvox.
D. PTU should be separated from melatonin.
E. There are no drug interactions present in the regimen.
 

B. PTU may decrease the anticoagulant effect of warfarin (increase risk of clotting).

Patient was a high metabolism state and now you're giving PTU to stop thyroid hormones and decrease metabolism. So less warfarin metabolized to active form leading to less free warfarin and decreased INR.

23

Which of the following statements is correct regarding levothyroxine tablet colors?

A. The 25 mcg tablet is orange and the 50 mcg tablet is yellow
B. The 100 mcg tablet is rose and the 88 mcg tablet is orange
C. The 50 mcg tablet is white and the 75 mcg tablet is violet
D. The 25 mcg tablet is green and the 100 mcg tablet is violet
E. The 50 mcg tablet is blue and the 100 mcg tablet is white
 

C.

Orangutans Will Vomit On You Right Before They Become Large Proud Giants

Orange (25), White (50), Violet (75), Olive (88), Yellow (100), Rose (112), Brown (125), Turquoise(137), Blue (150), Lilac (175), Pink (200), Green (300)

24

Which of the following drugs can cause hyperthyroidism? (Select ALL that apply.)

A. Amiodarone
B. Prednisone
C. Iodide
D. Lithium
E. Thyroid hormone taken in excess
 

A, C, E. Lithium causes only hypothyroidism. Amiodarone and interferons can cause either hypothyroidism or hyperthyroidism.

25

A patient with heartburn has been using OTC anti-gas and antacid products for many years. She has recently been diagnosed with hypothyroidism. Which of the following OTC medications will not interact with her thyroid medicine?

A. Magnesium hydroxide
B. Calcium carbonate
C. Aluminum hydroxide
D. Famotidine
E. Pepcid Complete
 

D. Medications that can decrease the absorption of thyroid hormone products include antacids (aluminum and magnesium hydroxide, calcium carbonate), the bile acid sequestrants cholestyramine, colestipol, cation exchange resins (sodium polystyrene sulfonate, SPS), ferrous sulfate, orlistat and sucralfate. Famotidine can be used, but Pepcid Complete cannot; it contains famotidine and antacids (calcium carbonate and magnesium hydroxide).

SE: none, Pregnancy (A), lots of DDI (polyvalent cation, iron, orlistat, svelamer, other-separate by 4 hours; lanthanum separate by 2 hours), beta-blockers, amiodarone, steroid, PTU can decrease conversion of T4 to T3

26

A patient gave the pharmacist a prescription for Tapazole 5 mg TID #90. Which of the following is an appropriate generic substitution for Tapazole?

A. Methimazole
B. Levothyroxine
C. Liothyronine
D. Thyroid USP
E. Propylthiouracil
 

A. The generic name of Tapazole is methimazole.

Levothyroxine (Synthroid, Levoxyl) - T4

Liothyronine (Cytomel, Triostat) - T3

Thyroid USP (Armour Thyroid, Nature-Throid) - T3/T4

27

Propylthiouracil can have this effect on blood cells:

A. Low white blood cells (leukopenia)
B. High white blood cells (leukocytosis)
C. Increased platelets (thrombocytosis)
D. Decreased red blood cells
E. Decreased platelets
 

A. Both PTU and methimazole have a risk of decreasing white blood cells, including a risk of agranulocytosis. Patients should watch for signs of infection.

Thionamides: inhibit synthesis of thyroid hormones by blocking oxidation of iodine in the thyroid gland; PTU also inhibits peripheral conversion of T4 to T3

Boxed warning: severe liver injury and liver failure (with PTU)

SE: GI upset, hepatitis, agranulocytosis (rare), pregnancy (D)

Propylthiouracil (PTU) is preferred under 2 scenarios: thyroid storm and 1st trimester of pregnancy. Otherwise use methimazole (Tapazole) in 2nd and 3rd trimester because less hepatoxicity compared to PTU

Take with food to minimize GI upset

28

The thyroid gland is the only organ which has the ability to absorb:

A. Triiodothyronine (T3)
B. Thyroxine (T4)
C. Iodine
D. TSH
E. Levothyroxine
 

C. The thyroid gland is one of the largest organs within the body’s endocrine system and is the only organ which contains cells that have the ability to absorb iodine.

29

Chief Complaint:  "I have no energy"
History of Present Illness:  KB is a 32 y/o female who comes into the outpatient clinic complaining of low energy, recent weight gain of 15 pounds, foggy memory, and feeling cold even though it is sunny outside. She is diagnosed with hypothyroidism and started on levothyroxine. 
Past Medical History: Allergic rhinitis, GERD, Hypothyroidism 
Current Medications: Cetirizine 10 mg PRN, Mylanta 20 mL Q6H, Tylenol 325 mg Q4-6H PRN, Omega-3 fatty acid 1 gram daily, MVI daily    
Vitals: 
Height: 5'7"  Weight: 138 lbs 
BP: 129/80 mmHg  HR: 85 BPM  RR: 20 BPM  Temp: 98.6ºF  Pain: 1/10    
3/10/14 Labs: 
Na (mEq/L) = 141 (135 - 145)                       
K (mEq/L) = 4.2 (3.5 - 5)                             
Cl (mEq/L) = 100 (95 - 103)                         
HCO3 (mEq/L) = 28 (24 - 30)                       
BUN (mg/dL) = 18 (7 - 20)                           
SCr (mg/dL) = 0.9 (0.6 - 1.3)                 
Glucose (mg/dL) = 110 (100 - 125) 
Mg (mEq/L) = 1.9 (1.3 - 2.1) 
PO4 (mg/dL) = 4.4 (2.3 - 4.7) 
Ca (mg/dL) = 9.5 (8.5 - 10.5) 
TSH (mIU/L) = 32 (0.3-3.0) 
Free T4 (mg/dL) = 0.3 (0.9-2.3) 
hCG-    
Plan:
Hypothyroidism.  Start levothyroxine 75 mcg daily.  Follow-up visit on 4/14/14.
4/14/14 Labs: 
Na (mEq/L) = 143 (135 - 145)                       
K (mEq/L) = 4.1 (3.5 - 5)                             
Cl (mEq/L) = 102 (95 - 103)                         
HCO3 (mEq/L) = 26 (24 - 30)                       
BUN (mg/dL) = 15 (7 - 20)                           
SCr (mg/dL) = 0.8 (0.6 - 1.3)                
Glucose (mg/dL) = 15 (100 - 125) 
Mg (mEq/L) = 1.8 (1.3 - 2.1) 
PO4 (mg/dL) = 4.1 (2.3 - 4.7) 
Ca (mg/dL) = 9.7 (8.5 - 10.5) 
TSH (mIU/L) = 4.7 (0.3-3.0) 
hCG+    
Question:
Was KB’s initial levothyroxine dose a full replacement dose based on her ideal body weight?

A. Yes, it was a full replacement dose.
B. No, the dose should have been 50 mcg daily
C. No, the dose should have been 100 mcg daily
D. No, the dose should have been 112 mcg daily
E. No, the dose should have been 125 mcg daily
 

C. KB is a healthy adult and should start with a full replacement dose. KB’s IBW is 61.6 kg (45.5 + 2.3x7). A full replacement dose is 1.6 mcg/kg/day x 61.6 kg = 98.56 mcg. Therefore the patient should have initially received levothyroxine 100 mcg daily. Partial replacement doses are used in the elderly, milder hypothyroidism and those with comorbidities.

For adults <50 years of age: 1.6mcg/kg/day (IBW) – full replacement dose

Elderly, mild disease, or co-morbidities: 25-50mcg/day (or 0.5mcg/kg/day) – partial replacement dose. We are concerned about cardiovascular problems and drug interactions

If known CVD: 12.5-25mcg/day

30

Jessie, a 43 year-old patient, has been diagnosed with hypothyroidism. Which of the following are signs/symptoms of hypothyroidism that Jessie may have experienced? (Select ALL that apply.)

A. An increase in weight
B. Low TSH
C. Diarrhea and oily skin
D. Depression
E. Feeling more tired than usual
 

A, D, E. Fatigue, weight gain, dry skin and constipation are common. Patients may feel depressed and suffer from memory impairment. They may have difficulty tolerating cold weather, the menstrual periods may be heavier, and hoarseness in their voice and coarseness in their hair (as well as hair loss) may occur. Untreated, long-term hypothyroidism puts patient at elevated risk of cardiovascular disease.

31

A patient gave the pharmacist a prescription for Armour Thyroid 60 mg once daily #30. Which of the following is a correct statement/s concerning Armour Thyroid? (Select ALL that apply.)

A. It contains both T3 and T4.
B. It is not the preferred agent for treating hypothyroidism.
C. It is not synthetic; it is derived from pork thyroid gland.
D. Some patients prefer it.
E. It will raise the TSH.
 

A, B, C, D. Some patients feel better using Armour Thyroid. Levothyroxine is the preferred agent, and there is no proof that Armour Thyroid works better, but some clinicians give it to patients on request or if they do not feel well enough on levothyroxine. Some feel that certain patients might not convert enough T4 to T3, but this is not proven. Armour Thyroid USP is manufactured according to good manufacturing practices (GMPs).

32

Chief Complaint:  "I have no energy"
History of Present Illness:  KB is a 32 y/o female who comes into the outpatient clinic complaining of low energy, recent weight gain of 15 pounds, foggy memory, and feeling cold even though it is sunny outside. She is diagnosed with hypothyroidism and started on levothyroxine. 
Past Medical History: Allergic rhinitis, GERD, Hypothyroidism 
Current Medications: Cetirizine 10 mg PRN, Mylanta 20 mL Q6H, Tylenol 325 mg Q4-6H PRN, Omega-3 fatty acid 1 gram daily, MVI daily    
Vitals: 
Height: 5'7"  Weight: 138 lbs 
BP: 129/80 mmHg  HR: 85 BPM  RR: 20 BPM  Temp: 98.6ºF  Pain: 1/10    
3/10/14 Labs: 
Na (mEq/L) = 141 (135 - 145)                       
K (mEq/L) = 4.2 (3.5 - 5)                             
Cl (mEq/L) = 100 (95 - 103)                         
HCO3 (mEq/L) = 28 (24 - 30)                       
BUN (mg/dL) = 18 (7 - 20)                           
SCr (mg/dL) = 0.9 (0.6 - 1.3)                 
Glucose (mg/dL) = 110 (100 - 125) 
Mg (mEq/L) = 1.9 (1.3 - 2.1) 
PO4 (mg/dL) = 4.4 (2.3 - 4.7) 
Ca (mg/dL) = 9.5 (8.5 - 10.5) 
TSH (mIU/L) = 32 (0.3-3.0) 
Free T4 (mg/dL) = 0.3 (0.9-2.3) 
hCG-    
Plan:
Hypothyroidism.  Start levothyroxine 75 mcg daily.  Follow-up visit on 4/14/14.
4/14/14 Labs: 
Na (mEq/L) = 143 (135 - 145)                       
K (mEq/L) = 4.1 (3.5 - 5)                             
Cl (mEq/L) = 102 (95 - 103)                         
HCO3 (mEq/L) = 26 (24 - 30)                       
BUN (mg/dL) = 15 (7 - 20)                           
SCr (mg/dL) = 0.8 (0.6 - 1.3)                
Glucose (mg/dL) = 15 (100 - 125) 
Mg (mEq/L) = 1.8 (1.3 - 2.1) 
PO4 (mg/dL) = 4.1 (2.3 - 4.7) 
Ca (mg/dL) = 9.7 (8.5 - 10.5) 
TSH (mIU/L) = 4.7 (0.3-3.0) 
hCG+    
Question:
Which drugs in KB’s medication profile will have a significant interaction with levothyroxine?

A. Mylanta and Tylenol
B. Cetirizine and MVI
C. Omega-3 fatty acid and Cetirizine
D. MVI and Mylanta
E. Mylanta and Omega-3 fatty acid
 

D. Aluminum (antacids), calcium, cholestyramine, iron, magnesium, multivitamins (containing ADEK, folate, iron), orlistat (Xenical, Alli), sevelamer, sodium polystyrene (Kayexalate), and sucralfate all decrease thyroid hormone absorption. Doses should be separated by 4 hours.

Decks in Pharmacy Class (61):