pharm wk 6

Question 1

what to do in patient with thyroid nodules

Answer 1

Recognize which patients with thyroid nodules require fine needle biopsy for cytologic diagnosis versus observation

Question 2

thyrotoxicosis vs hyperthyroid vs thyroid storm

Answer 2

Thyrotoxicosis is any condition of excessive thyroid hormone and its effects

Hyperthyroidism is specifically due to excess thyroid hormone production

Thyroid storm if a life-threatening medical emergency caused by severe thyrotoxicosis

Question 3

causes of thyrotoxicosis

Answer 3

graves disease, toxic nodules, iodine excess, and TSH-producing pituitary adenomas, among others

Question 4

non pharmalogical choices for hyperthyroid

Answer 4

Important to consider surgery as an option given the limitations of medication and the potential for the formation of goitre

Hypothyroidism is a common and likely adverse effect thyroid surgery

Question 5

what is the form of radioactive iodine used

Answer 5

iodine 131

Question 6

what is iodine 131 used in

Answer 6

Used to ablate thyroid tissue in patients with Graves disease and toxic nodules

The thyroid rapidly concentrates iodine, so an oral dose has minimal effect on the rest of the body

Beta wave emission destroys surrounding tissue within a range of 0.6 – 2 mm

Question 7

adverse effects of using radioactive iodine (iodine 131 to kill tissue in graves and toxic nodules)

Answer 7

High risk of hypothyroidism

Possible worsening of Graves orbitopathy

Risk of radiation thyroiditis

Question 8

what does methimazole do ? what does it effect? what does it not effect?

Answer 8

Decreases the production of thyroid hormone

Interferes with iodination of tyrosine as well as with coupling

Does not affect stored thyroid hormone or thyroid hormone in circulation

Question 9

adverse effects of methimazole

Answer 9

Risk of skin rash, allergic reaction, and agranulocytosis

Can cause hepatotoxicity in rare instances

Contraindicated during the first trimester of pregnancy due to causing aplasia cutis

Question 10

what can methimazole cause in pregnancy

Answer 10

aplasia cutis

Contraindicated during the first trimester of pregnancy due to causing aplasia cutis

Question 11

what is an example of beta blockers

Answer 11

propanolol

Question 12

what is the thyroid hormone given in hypothryoid

Answer 12

levothyroxine

Question 13

what are the 2 antithyroid agents

Answer 13

methimazole and propylthiouracil

Question 14

PROPYLTHIOURACIL is similar to what

Answer 14

methimazole

Question 15

what do propylthiouracil do

Answer 15

Similar mechanism of action to methimazole

Has the additional action of inhibiting the conversion of T4 to T3 in the periphery

Affects production of thyroid hormone and existing thyroid hormone

Question 16

adverse effects of propylthiouracil

Answer 16

Similar adverse effects to methimazole

Risk of skin rash, allergic reaction, and agranulocytosis

Can cause severe hepatotoxicity that may be fatal in rare instances

Does not cause aplasia cutis

Question 17

METHIMAZOLE VS PROPYLTHIOURACIL

a. in most instances?
b. in breastfeeding and kids?
c. 1st trimester pregnancy?
d. thyroid storm treatment?

Answer 17

m
m
p
p

Methimazole is the preferred drug in most instances due to the lower risk of causing hepatotoxicity

Methimazole is the preferred drug while patients are breastfeeding and in children

Propylthiouracil is the preferred drug during the first trimester of pregnancy

Propylthiouracil can be used to treat thyroid storm as it affects thyroid conversion in the periphery

Question 18

what to use for thyroid storm

Answer 18

Propylthiouracil

Question 19

what to use in 1st trimester of pregnancy

Answer 19

Propylthiouracil

Question 20

what has a lower risk of hepatotexocithy ; METHIMAZOLE VS PROPYLTHIOURACIL

Answer 20

METHIMAZOLE

Question 21

what do beta blockers not effect

Answer 21

thyroid hormone production

Question 22

what do beta blockers effect

Answer 22

Used to ameliorate the symptoms of adrenergic excess caused by excess thyroid hormone (elevated heart rate, hypertension, etc.)

Question 23

propanolol (beta blocker) can decrease what

Answer 23

Propranolol can decrease the conversion of T4 to T3 in the periphery

Question 24

adverse effects of beta blockers/ propanolol

Answer 24

Bradycardia, dizziness, fatigue, headache, hypotension.

Avoid in patients with asthma or conditions associated with bradycardia; taper once thyrotoxicosis improves.

Question 25

who should not take propanolol/ beta blocker

Answer 25

patients with asthma or conditions associated with bradycardia; taper once thyrotoxicosis improves.

Question 26

what is common vs uncommon cause of hypothyroid

Answer 26

Rarely caused by iodine deficiency in North America Most commonly caused by Hashimoto’s thyroiditis

Question 27

what is the standard treatment for hypothryoid

Answer 27

levothyroxine

Question 28

what is levothyroxine

Answer 28

Replacement therapy – essentially treatment using orally administered T4

Question 29

how long does it take to get to a steady state with levothyroxine

Answer 29

Takes 6 weeks to attain a new steady state after dosage adjustments wait 6 weeks to adjust dose

Question 30

what is levothyroxine dosing based on

Answer 30

Generally based on lean body mass Elderly patients may need less For those at risk of angina start lower

Question 31

dosing of levothyroxine depends on

Answer 31

depending on endogenous thyroid function In patients with an intact thyroid or with mild or subclinical disease much smaller initial dosages may be needed (25 – 50 mcg) In patients with negligible thyroid function full replacement dosages may be needed

Question 32

interactions of levothyroxine

Answer 32

Absorption may be reduced by antacids and mineral supplementation Proton pump inhibitors and estrogens may interfere with absorption Variable effects with anticoagulant drugs Separate administration by 6 hours Levothyroxine is typically taken first thing in the morning before any other medications

Question 33

adverse effects of levothyroxine

Answer 33

Symptoms of hyperthyroidism if overtreated Possible exacerbation of angina Glycemic control may decline with initiation of levothyroxine, potentially necessitating dosage adjustment of antihyperglycemic agents

Question 34

what is desiccated thyroid

Answer 34

Tablets contain T4 and T3 in fixed amounts thyroid hormone pill made from animal thyroid gland

Question 35

adverse effects of desiccated thyroid

Answer 35

Similar to levothyroxine Risk of cardiovascular and neurological adverse effects increases with larger doses (due to T3) - palpitation, tachycardia, cardiac arrhythmias, angina pectoris - nervousness, tremors, headache, insomnia - sweating, heat intolerance, fever, weight loss

Question 36

what added risk does desiccated thyroid have compared to levothyroxine

Answer 36

CVD and neurological bc of the T3

Question 37

typical dose calculation for levothyroxine

Answer 37

1.6 x weight in kg but also take into account BMI, TSH level, symptoms, age, etc

Question 38

A patient returns for follow-up 6 weeks after receiving their first prescription for levothyroxine and their TSH value remains unchanged. The patient reports taking it every morning with the iron supplement they were also prescribed. Which of the following is the best course of action? A. Increase the dose of levothyroxine by 12.5 mcg B. Reduce the dose of levothyroxine by 12.5 mcg C. Switch the patient to an equivalent dose of desiccated thyroid D. Change the time the patient takes their iron supplement

Answer 38

D. Change the time the patient takes their iron supplement

Question 39

what affects levothyroxine absorption

Answer 39

antacids and mineral supplements take separately

Question 40

***DOSING FOR THYROID MED CASES***