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Nurs 5229 Clinical Pharmacotherapeutics > Thyroid > Flashcards

Flashcards in Thyroid Deck (51)
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1
Q

Thyroid is a

A

2-lobed gland

2
Q

Thryoid follicular cells oxidize iodide in process of

A
producing
triiodothyronine (T3) and thyroxine (T4)
3
Q

Pituitary gland secretes

A

thyroid-stimulating hormone (TSH) which

controls rate and release of T3 and T4

4
Q

Hypothalamus secretes

A

thyrotropin- releasing hormone which

regulates the release of TSH

5
Q

Low levels of serum thyroid hormones cause

A

increased secretion of

TSH, and subsequently T3, T4

6
Q

Most of T3 and T4 is

A

bound, free T3 and T4 regulate metabolism

7
Q

Hypothyroidism is a deficiency of

A

T4 usually. or a deficiency of iodine

8
Q

Autoimmune or Hashimoto’s thyroiditis

A
  • Infiltration of thyroid by lymphocytes
  • Leads to fibrosis and decreased function of the gland
  • May present with goiter, be euthyroid or hypothyroid
  • Anti-thyroid antibodies serum titers are high
9
Q

Primary hypothyroidism labs

A

High TSH (usually
≥ 10mlU/L
Low T4

10
Q

Secondary

(central) hypothyroidism labs

A

Low T4
Do not see inverse
appropriate
elevation in TSH

11
Q

Subclinical (early
hypothyroidism,
pre-clinical
hypothyroidism) labs

A

Normal T4

Elevation TSH

12
Q

Transient hypothyroidism labs

A

phas of subacute thyroidits

13
Q

Hypothyroidism S/S

A

• Symptoms
• Fatigue, constipation, weight gain, changes in menses
• Elderly: more subtle signs; ataxia, parasthesia, carpal tunnel,
psychiatric changes
• P.E.
• Thyromegaly, bradycardia, peripheral edema

14
Q

Hypothyroidism LAB tests to do

A
  • TSH (most widely used screening test), free T4

* Total cholesterol and LDL elevated

15
Q

Hypothyroidism goal of treatment

A

• Restore patient to euthyroid state

16
Q

Hypothyroidism products

A
  • Natural thyroid extract
  • T3 replacement (liothyronine)
  • Liotrix (T3 and T4 combination product)
  • Levothyroxine (T4), most common
17
Q

Hypothyroidism when to initiate therapy

A

• TSH ≥ 10mlU/L
• TSH levels 5 -10 μIU/mL with goiter or positive antithyroid peroxidase
antibodies (or both).

18
Q

Synthetic Levothyroxine

(Synthroid) Fast Facts

A
  • Preparation of choice for thyroid replacement and suppression
  • Stable compound
  • Uniform content
  • Low cost
  • Lack of allergenic foreign protein
  • Easy lab measurement of serum levels

• Generic form has comparable efficacy to brand and is more
cost-effective, but don’t alternate (DO NOT ALTERNATE)

19
Q

Levothyroxine is easily

A

Easily absorbed from GI tract but erratic absorption

20
Q

Levothyroxine is what exactly

A

Synthetic T4

21
Q

Levothyroxine how does it work

A

T4 is converted to T3 so replaces both
• Peak T4 serum level in 2-4 hours
• Peak T3 slower because of time needed for conversion

22
Q

Levothyroxine has a

A

Long half-life allows once-daily dosing

23
Q

Levothyroxine elimination

A

Elimination: bile/feces

24
Q

Levothyroxine requires

A

Requires 1 month to reach steady state

25
Q

Consideration for Dosage of Levothyroxine

A

Patient’s age, duration of hypothyroidism, comorbidities

26
Q

Thyroid hormones (levothyroxine) are safe in

A

Pregnancy: safe; increased metabolic rate during pregnancy may
necessitate higher dosing from baseline

27
Q

You should recheck TSH in

A

6 to 8 weeks. Then in 6 months if stable. Can push this longer the more stable they are.

28
Q

Goal TSH

A

0.4-4.0*

29
Q

Levothyroixine should be taken

A

on an empty stomach

30
Q

Levothyroxine in younger adults

A

adult patients or those with mild disease,

can start with full replacement (75-100mcg/d)

31
Q

Levothyroxine related to hormone level, monitor

A

Related to hormone level: monitor TSH every 3-6 months

after dose established and after changes, then annually

32
Q

Levothyroxine children ADR

A

restlessness, insomnia, accelerated bone

maturation and growth

33
Q

Levothyroxine Adults ADR

A

increased nervousness, heat intolerance,
episodes of palpitations, tachycardia, chest pain, flushing
or unexplained weight loss

34
Q

Levothyroxine Elderly ADR

A

chronic overtreatment increases the risk of atrial

fibrillation and accelerated osteoporosis

35
Q

Levothyroixine drug interactions

A

Bile-acid sequestrants, iron salts, and antacids decrease
absorption; estrogens may decrease response.
• Drugs may decrease action of warfarin, digoxin, and beta
blockers.

36
Q

Hyperthyroidism is a

A

Excess amount of thyroid hormone

37
Q

Grave’s Disease

A
  • Stimulation of thyroid gland by TSH receptor autoantibodies
  • Usual negative-feedback mechansim bypassed
  • Increased levels of thyroid hormones
38
Q

Plummer’s Disease

A

• Toxic nodular goiter: hyperactive thyroid nodule

39
Q

Thyrotosicosis Factitia

A

• Patient intentionally takes high doses of T4

40
Q

Hyperthyroidism symptoms

A

Symptoms
• Palpitations, sweating, heat intolerance, weight loss
• P.E.
• Elevated BP, tachycardia, bruit over thyroid, exophthalmus
(Grave’s disease)

41
Q

hyperthyroid diagnsotic testing

A
  • Low or suppressed TSH, high free T4

* Nuclear thyroid scan is diagnostic

42
Q

Treatment of Hyperthyroidism Antithyroid drugs

A

• Used in younger patients because of cancer concerns from

radioactive iodine

43
Q

• Radioactive iodine ablation

A
  • Adults over 40, increasingly used in younger patients also

* Contraindicated in pregnancy

44
Q

treatment options for hyperthyroidism

A

Antithyroid drugs
• Used in younger patients because of cancer concerns from
radioactive iodine
• Radioactive iodine ablation
• Adults over 40, increasingly used in younger patients also
• Contraindicated in pregnancy
• Surgery

45
Q

Antithyroid Drugs MOA

A

Reduce thyroid activity and hormone effects
• Mechanism of action
• Interfere with production of thyroid hormones
• Modify the tissue response to thyroid hormones
• Glandular destruction with radiation or surgery

46
Q

Goitrogens

A

Agents that suppress secretion of of T3 and T4 to
subnormal levels
• Inversely increase TSH which in turn produces
glandular enlargement
• Antithyroid compounds used clinically include:
• Thioamides
• Iodides
• Radioactive Iodine

47
Q

Thiourelynes - 2 main drugs

A

2 main drugs: methimazole and propylthiouracil

48
Q

Thiourelynes - MOA

A

Major action: prevent hormone synthesis by
inhibiting the thyroid peridoxase-catalyzed reaction
to block iodine organification

49
Q

Thiourelynes have

A

Short half-lives

50
Q

Thiourelynes metabolized

A

• Metabolized in the liver

51
Q

Thiourelynes high

A

relapse rates exist but are less likely if treated

for 18 to 24 months