Endocrine: 9. Maloney : Thyroid Pharm

Front 1

47-year-old female presents at her family practice physician complaining of fatigue and chronic constipation. She states that she is always cold and has gained 10 lbs in the last 4 months, even though she has not had much of an appetite. Physical exam revealed dry skin, non-pitting edema in her lower extremities, a somewhat puffy face, and a slightly enlarged thyroid. A test was positive for thyroid peroxidase antibodies. What would you most likely see on her lab test? 3

Back 1

fatigue, always cold . gained weight, not much appetite, edema, puffy face [Metabolism not so good, hyaluronic acid accumulates in skin (edema), goiter]

This bitch is hypothyroid

so Low T3/T4, Elevated TSH

Front 2

How does Hashimoto's thyroiditis work? what 2 things are elevated

Back 2

altered T cell–mediated immunity causes destruction of thyroid tissue and impaired gland function. (Patients have high serum concentrations of antibodies to thyroid peroxidase and thyroglobulin.)

Front 3

What are possible treatment options for primary hypothyroidism (eg. from Hashimoto’s thyroiditis)?

A) T3
B) T4
C) TSH
D) TRH
E) Dopamine Agonist

Back 3

A) T3
B) T4

Front 4

What are possible treatment options for secondary hypothyroidism (eg from pituitary dysfunction)?

A) T3
B) T4
C) TSH
D) TRH
E) Dopamine Agonist

Back 4

A) T3
B) T4

we have no drug that is analogous to TSH

Front 5

for any form of hypothyroidism what is the treatment?

Back 5

Thyroid hormone! (T3/4)

this means for primary, or secondary, or tertiary

Front 6

what type of drug is Levothyroxine?

Back 6

T4

Front 7

what type of drug is Liothyronine

Back 7

T3

Front 8

clinical use of synthetic thyroid hormone?

Back 8

T3-Liothyronine
T4-Levothyroxine?

Hypothyroidism
TSH suppression therapy in patients with thyroid cancer
Occasionally those with nontoxic goiter

Front 9

Why would you use levothyroxine in a euthyroid patient with a nontoxic goiter?

Back 9

Decrease the release of TSH from the pituitary and decrease the growth and size of the goiter

Front 10

Which is preferred for hormone thyroid replacement therapy? Why? 2

Back 10

levothyroxine (T4) is preferred over liothyronine (T3) for hormone replacement therapy

Why:

T4 is converted into T3

T4 has a longer half life than T3

Front 11

When might you want to use liothyronine (T3)

Back 11

if a pt has a myxedema coma and want a faster onset

Front 12

A 37-year-old female presents to your clinic for unintentional weight loss. Over the past 3 months, she has lost approximately 15 lb without changing her diet or activity level. Otherwise, she feels great. She has an excellent appetite, no gastrointestinal complaints except for occasional loose stools, a good energy level, and no complaints of fatigue. She denies heat or cold intolerance. Her heart rate is 108 bpm, blood pressure 142/82 mm Hg, and she is afebrile. When she looks at you, she seems to stare, and her eyes are somewhat protuberant. You note a large, smooth, nontender thyroid gland, and her skin is warm and dry. There is a fine resting tremor. She most likely has:

Back 12

Weight loss-metabolism is too good
increased BPM- increased catecholamine sensitivity (NE/EPI)
eyes are protuberant- inflitrative ophthalmopathy

Grave's Disease

Front 13

Diffuse simple goiter--->

Grave's disease--->

Hashimoto's Thyroiditis--->

Myxedema--->

Cretinism-->

Riedel thyroiditis-->

what is each?

Back 13

Diffuse simple goiter---> Iodine deficiency (Euthyroid or hypothyroid)

Grave's disease---> Autoantibodies to TSH receptor

Hashimoto's Thyroiditis-->Autoimmune destruction

Myxedema--->Hypothyroidism in adult

Cretinism-->hypothyroid in child

Riedel thyroiditis-->thyroid atrophies (fibrosis)

Front 14

Propranolol would be useful in treating which symptoms of graves disease? 3

Back 14

Tachycardia

HTN

Tremor (block B2 on skeletal muscle)

Front 15

How else can you treat her hyperthyroidism?

Inhibit thyroid hormone synthesis

Inhibit thyroid hormone release

Inhibit the thyroid hormone receptor

Destroy thyroid tissue

Back 15

Inhibit thyroid hormone synthesis

Inhibit thyroid hormone release

Destroy thyroid tissue

(note: we do not have drugs that
Inhibit the thyroid hormone receptor)

Front 16

What do thioamide drugs do?

Iodide salts?

Radioactive iodine?

Back 16

What do thioamide drugs do? inhibit synt

Iodide salts? inhibit synth/release

Radioactive iodine? destroy tissue

for hyperthyroid

Front 17

What type of drug is Methimazole

Back 17

Thioamides

inhibit synt of TH (blocks thyroid peroxidase)

Front 18

What type of drug is Propylthiouracil

Back 18

Thioamides

inhibit synt of TH (blocks thyroid peroxidase)

Propylthiouracil also partially inhibits the peripheral deiodination of T4 to T3

Front 19

What enzyme catalyzes the reaction between iodide, H2O2 and TG to form MIT and DIT, and the coupling reaction between MIT and DIT to form T3 and T4?

Back 19

Thyroid peroxidase

Front 20

What enzyme is involved in the conversion of T4 to T3 in peripheral tissue?

Back 20

Thyroid hormone deiodinase

Front 21

• MOA for thioamides?

Back 21

o Inhibits thyroid peroxidase (TPO)-catalyzed reactions thereby blocking iodine organification (production of MIT, DIT) and iodotyrosine coupling (production of T3, T4).
o Propylthiouracil also partially inhibits the peripheral deiodination of T4 to T3

Front 22

• How quickly will methimazole reduce serum levels of thyroid hormone (i.e. be effective in treating hyperthyroidism)?

Back 22

o A few weeks

Front 23

• Clinical use of Thioamides?

Back 23

HYPERTHYROIDISM

o Control disorder while waiting for spontaneous remission of Grave’s disease
 Leave thyroid intact
 12-18 months of treatment
 High chance of relapse
o To control disorder (i.e. make euthyroid) before radioactive iodine or surgical treatment

Front 24

• Which thioamide would be most useful in a patient who presents with symptoms of a thyroid storm? (Methimazole or Propylthiouracil)

Back 24

o Either
o Advantage of propylthiouracil- inhibits T4 to T3, so could be faster
o Advantage of Methimazole- longer half life, so don’t have to administer as often, fewer side effects

Front 25

• Adverse effects of thioamides?

Back 25

o Maculopapular pruritic rash
o Arthralgias
o Fever
o Nausea
o Rare but potentially fatal
Agranulocytosis
Hepatotoxicy

remember: these inhibit synt of TH (blocks thyroid peroxidase)--ex: propylthiouracil

Front 26

• In a pregnant female with hyperthyroidism, what drug would you likely give? Why?

Back 26

o Propylthiouracil is more strongly bound to plasma proteins. Therefore it crosses the placenta less readily and thioamide of choice for pregnancy.
- This is questionable though

Front 27

• What is the difference in using high levels of iodide salts and radioactive iodide to treat hyperthyroidism?

Back 27

o Iodide salts—the effect is reversible and transient. Improvement is seen w/in 2-7 days but limited to several weeks
o Radioactive iodide—the effect is permanent. Usually takes several weeks to restore thyroid hormone levels to ‘normal’

Front 28

• Clinical use of Iodide salts? 2

Back 28

o Thyroid Storm (inhibit release of thyroid hormone, rapid improvement>2-7 days)
o Preoperative (Decrease vascularity, size and fragility of the hyperplastic thyroid)

Front 29

• Should iodide salts be used before and/or after radioactive iodine?

Back 29

ONLY AFTER

if given before it will compete with radioactive I (not as good of an effect)...you want it all to concentrate in the cell

Front 30

What is the biggest side effect of radioactive iodide?

Back 30

hypothyroidism

Front 31

• How does I 131 work?

Back 31

o Kills the tissue in the Thyroid

Front 32

• How do iodine salts work?

Back 32

o Prevent synthesis and release of TH

Wolf effect...too much I overfloods the cell