Thyroid Agents COPY Flashcards

1
Q

Levothyroxine (Synthroid) MOA

A
  • synthetic form of T4 - produces the same effects in the body as endogenous thyroid hormones - used to treat hypothyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Levothyroxine (Synthroid) ADRs

A
  • CV: angina, BP increase, flushing, palpitations,
  • CN: anxiety, headache, insomnia

Generally minimal side effects if adequate level maintained

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

Levothyroxine contraindications

A
  • caution in pts with CV disease (relative contraindications - start with a lower dose) - avoid after recent MI, thyrotoxicosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Levothyroxine pt education

A
  • take in the morning, preferably before breakfast on an empty stomach to increase absorption
  • do not take with any other medications/supplements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Methimazole (Tapazole) MOA

A
  • inhibits the synthesis of thyroid hormones (mostly T4) by blocking the oxidation of iodine in the thyroid gland - used to treat the side effects of hyperthyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Methimazole (Tapazole) ADRs

A
  • urticaria (hives) - agranulocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Methimazole (Tapazole) Contraindications

A
  • Not safe in the 1st trimester of pregnancy (ok for use in 2nd and 3rd trimester)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Methimazole (Tapazole) patient education

A
  • recommend that the patient not get pregnant while on these drugs
  • 1-2 years of treatment typically required
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Propylthiouracil (PTU) MOA

A
  • inhibits the synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland - blocks conversion of T4 to T3 in the peripheral tissues - used to treat the side effects of hyperthyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

PTU ADRs

A
  • urticaria - agranulocytosis - hepatitis (very hard on the liver)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

PTU Contraindications

A
  • black box warning: hepatotoxicity - PTU is safe in the 1st trimester of pregnancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does propylthiouracil differ from methimazole?

A

PTU also inhibits T4 to T3 conversion in peripheral tissues

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

Drug of choice for pregnant women with graves disease in first trimester

A

Prophylthiouracil

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

Hyperthyroidism: Radioactive Iodine treatment indications

A

older adults, cardiac patients, moderate-severe symptoms, and those that fail treatment with antithyroid drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Explain the biofeedback mechanism of the HPO axis as it relates to thyroid hormones

A

The hypothalamus senses low circulating levels of thyroid hormone (Triiodothyronine (T3) and Thyroxine (T4)) and responds by releasing thyrotropin-releasing hormone (TRH). The TRH stimulates the anterior pituitary to produce thyroid-stimulating hormone (TSH). The TSH, in turn, stimulates the thyroid to produce thyroid hormone until levels in the blood return to normal. Thyroid hormone exerts negative feedback control over the hypothalamus as well as anterior pituitary, thus controlling the release of both TRH from hypothalamus and TSH from anterior pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Levothyroxine in pregnancy

A
  • Levothyroxine is safe in pregnancy
  • Increases in dose may be required