Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 1: Patho/Pharm > Thyroid PHARM > Flashcards

Thyroid PHARM Flashcards

1
Q

Levothyroxine
MOA

A

Synthetic T4
Tetra-iodothyronine

Converted in periphery to T3
Tri-iodothyronine
biologically active
transcription factor
transcription of genes involved in

  1. BMR
  2. Heart
  3. Growth & Development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Levothyroxine
Half life and patient monitoring

A

Half life is 7 days
It takes 28 days (approximately 4-6 weeks) to reach therapeutic effect

Patient monitoring
4-6 week mark
annually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Levothyroxine
SE

A

Thyrotoxicosis if level is too high

Cardio:
tachycardia, racing heart
tachydysrhythmias, palpitations
increase metabolic demand of heart
angina pain

BMR:
hyperthermia (heat intolerance)
diaphoresis
hyperglycemia
Accelerated bone loss
Weight loss

CNS:
nervousness
anxiety
tremor
racing thoughts
insomnia

*More common in elderly

Hypothyroidism if level is too low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Levothyroxine
AE

A

Thyrotoxicosis
Heart: dysrhythmias, tachycardia, angina, ischemia
BMR: bone, muscle, glycogen reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Levothyroxine
Drug interactions

A

Drugs decrease absorption:
antacids
H2 antagonists
PPIs
sucrafalate
bile acid sequestrates

Drugs that increase metabolism:
AED
SSRIs

Antagonistic to these drugs:
Digoxin
Beta blockers
insulin and hypoglycaemic agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

PRN prescriptions
accompany levothyroxine

A

Vitamin D3
Calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Levothyroxine and pregnancy

A

Increase BMR during pregnancy
Requires increase dosage in first trimester
Baby does not produce thyroid hormone and dependent for normal growth and development

Dosage plateaus in second and third trimester

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Levothyroxine and neonatal hypothyroidism

A

Requires thyroid hormone for normal growth and development
within 4 weeks to prevent irreversible growth, development, and CNS effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Patient Education
Levotyroxine

A

Brands are not interchangable

Change of dose requires monitoring blood 4-6 weeks

TSH monitoring

Take on empty stomach, 1 hour before eating

Therapy is life long and required for survival

Report S&S dosage is too high: palpitations, chest pain, tremor, nervousness, insomnia, sweating, heat intolerance

Take calcium and vitamin D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Levothyroxine
Patient monitoring

A

Monitor every 6-8 weeks until TSH normalizes and then annually

Serum: TSH, T4

Children: monitor height (normal growth, development)

Symptoms: hyper or hypothyroidism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Indications
Levothyroxine

A

Hypothyroidism

Congenital hypothyroidism (neonate)

Myexedema coma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Examples
Synthetic Thyroid Hormone

A

T4: levothyroxine
T3: Liothyronine
T3/T4: Liotrix (mixture)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Methiomazole (MMI)
MOA

A
  1. Blocks peroxidase enzyme in the thyroid follicular cell: prevents oxidation of iodide to iodine (cannot be added to tyrosine)
  2. Blocks coupling of iodinated tyrosines (blocks synthesis of T3 and T4)

*3-12 weeks to take effect
Thyroid colloid cells have T3 and T4 stores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Indication and Duration of therapy
Methimazole (MMI)

A

Hyperthyroidism
First line therapy

Grave’s Disease

Pre-surgical prophylaxis: prevent thyroid storm

Thyrotoxicosis

Duration: 1-2 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Methimazole
Special populations and contraindications

A
  1. Pregnancy and breast feeding
    - not to be taken in first trimester
    - caution breast feeding
    - neonatal hypothyroidism and goitres
  2. Liver disease
    - AE: hepatitis and liver failure
  3. Blood dyscrasia
    - AE: agranulocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Methimazole
SE

A

Hypothyroidism
- dosage too high
- monitor S&S: brittle hair, nails, cold, fatigue, lethargy, weight gain, depression, mental slowing

Liver disease
- hepatitis and liver failure
- S&S: anorexia, n/v, dark urine, jaundice, RUQ pain

Agranulocytosis
- Requires D/C and treatment with PRN filgastrim
- S&S: infection, fever, sore throat

16
Q

Patient Education
Methiomazole

A

Women child bearing age
- teratogenic first trimester
- contraception and child planning

Monitor S&S liver disease

Monitor S&S infection

Monitor S&S hypothyroidism

17
Q

Blood Monitoring
Methimazole

A

Baseline:
CBC (SE: agranulocytosis)
LFTs (SE: liver disease)
TSH, T3, T4 (dosing)
HCG (SE: teratogenic first trimester)

Follow up:
CBC
LFTs
S&S hypothyroidism

18
Q

Methimazole
Pregnancy and Breastfeeding

A

Free
Crosses placenta
Not safe in first trimester
*does not enter breast milk

19
Q

Propylthiouracil (PTU)
MOA

A

Blocks the conversion of T4 (tetraiodothyronine) to T3 (triiodothyronine) in the periphery

T3 is the bioactive thyroid hormone

20
Q

Propylthiouracile (PTU)
Indications

A

Second line therapy

Hyperthyroidism
Pregnancy
First line therapy , first trimester

Thyroid Storm
First line therapy - direct action, prevent conversion to bioactive form

21
Q

Propylthiouracil (PTU)
AE

A

Liver failure without warning
much more common and severe

*used in the first trimester of pregnancy (does not cross placenta or into breast milk)

22
Q

Propylthiouracil (PTU)
SE

A

Hypothyroidism:
Lethargy, low BMR, low HR, low BP, cold intolerance, weight gain, brittle hair and nails, etc.

Liver failure

23
Q

Patient education
Propylthiouracil (PTU)

A

Monitor S&S liver disease; anorexia, nausea, vomiting, fullness, abdominal pain, jaundice, dark urine, pale stools

Monitor S&S hypothyroidism: low HR, BP, fatigue, lethargy, depression, cold intolerance

24
Q

Radioactive Iodine (I-131)
Indication

A

Hyperthyroidism
Failure thionamides
Failure surgical resection

Prophylaxis surgical resection

Thyroid storm

25
Q

Radioactive Iodine (I-131)
Contraindications

A

Pregnancy

Breastfeeding

Children
- lifelong thyroid therapy

26
Q

Radioactive Iodine I-131
MOA

A

Taken up by thyroid follicular cells
radioactive iodine decays
beta particles (harmful) damage follicular cells
gamma particles (harmless)

27
Q

Radioactive Iodine I-131
SE/AE

A
  1. Delayed hypothyroidism
    life long thyroid hormone dependence
    more common children
    *contraindication pregnancy, breastfeeding
  2. Effects take weeks or months
    - require thionamide therapy while waiting
  3. Iodism
    - GI corrosion, perforation, bleeds
    - bleeding gums
    - brassy taste
28
Q

Thyroidectomy
Indications

A

Hyperthyroidism

Thyroid carcinoma

Goitres

29
Q

Thyroidectomy
Complications

A

Infection

Hypothyroidism

Hypoparathyroidism

Damage to laryngeal nerve

Thyroid storm

30
Q

Non-Radioactive Iodine (Lugol)
MOA

A

High concentration of iodine inhibits thyroid gland
- decreases iodine uptake
- decrease T3, T4 synthesis (iodination, coupling, release)

31
Q

Non-Radioactive Iodine (Lugol)
Indications

A

Prophylaxis pre-surgery to prevent thyroid storm

Thyroid storm
10ggt Q8 hours

*tolerance develops with long term use
Peak 10-15 days

32
Q

Pregnancy
Hyperthyroidism treatments

A

Contraindicated
- Methimazole first trimester (neonatal hypothyroidism, goitre)
- radioactive iodine

Approved
- propylthiouracil (PTU) first trimester
- MMI second and third trimester

33
Q

Pregnancy
Hypothyroidism treatment

A

All women screened in first trimester for hypothyroidism
- congenital growth, development, CNS defects

Increase thyroid hormone demands in first trimester by 30-50%
- baby doesn’t make thyroid hormone until 2nd and 3rd trimester

Increased monitoring
- dosage plateau in 2nd and 3rd trimester

34
Q

Paediatrics
Hyperthyroidism treatment

A

Contraindicated
- radioactive iodine - thyroid hormone dependence
- propylthiouracil - liver failure

Approved
- surgery
- MMI weight based dosing

35
Q

Paediatric hypothyroidism

A

Treat right away
prevents growth, development, CNS (learning, memory, IQ)
must be treated within 4 week window of being born to prevent permanent deficits

Year 1: Patho/Pharm (39 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions