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STEP Pharm II > Drugs Hypothalamic/Pituitary/etc. > Flashcards

Drugs Hypothalamic/Pituitary/etc. Flashcards

1
Q

What is IGF-2 used for?

A

gestational growth (note that GH is only present after birth)

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2
Q

What are some drug analogs of GH?

A

Somatropin (brand names Serstim, Genotropin, Humatrope, Nutropin, and Saizen)

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3
Q

What are some drug analogs of IGF-1 (aka somatomedin C)?

A

Mecasermin (Increlex)NOTE: IGF-1 is made mostly in the liver.This drug is not to be confused withmecasermin rinfabate(trade name Iplex), which is a combination of recombinant human IGF-1 (rhIGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3). IGFBP-3 serves to prolong the action of IGF-1 in the human body.

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4
Q

What is a GH antagonist?

A

Pegvisomant (Somavert)

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5
Q

What are some somatostatin (somatotroph antagonist) analogs?

A

Octreotide (Sandostatin)Lanreotide (Somatuline LA)- better choice because its longer-acting BUT costs way more

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6
Q

What are some dopamine agonists (aka prolactin antagonists)?

A

Cabergoline (dostinex)- higher affinity for D2 receptors, longer half-lifebromocriptine (Parlodel)- not well tolerated but FDA approved

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7
Q

How is GH released?

A

GH is released in a pulsatile manner, thus, measuring GH levels is meaningless. Note that hypoglycemia is one factor that stimulates GH release while hyperglycemia would inhibit itGH represents almost 50% of all anterior hormones released

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8
Q

What are the actions of GH again?

A

The main effects of GH are either through direct action of via action of IGF-1 and consist of increased protein synthesis and linear growth, as well as increased lipolysisNOTE: GH opposes the effects of insulin, and thus hypoglycemia is a symptom of children with deficient GH

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9
Q

T or F. A child deficient of GH during gestation will be small for its gestational age

A

F. GH is not needed for prenatal growth

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10
Q

Would a GH deficient adult be skinny or fat?

A

Fat because of GH’s actions of mediating lipolysis

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11
Q

What is Sermorelin acetate?

A

GHRH analog that has been discontinued

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12
Q

How should GH deficiency in childhood be treated?

A

hGH therapy in children is most effective in the first 2 yrs of life and therapy should continue until growth stops.

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13
Q

What are the AEs of hGH therapy in children?

A

Few AEs but some children develop ntracrnail HTN, papilledema, visual changes, HA, and N/V

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14
Q

What malignancy has been associated with hGH use in children?

A

Leukemia (thus hGH should NOT be used within 1-2 yrs following treatment of pediatric leukemia tumors)

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15
Q

AEs of hGH in adults?

A

This leads to wanted effects such asincreased muscle mass and bone and decreased fat, but may lead toperipheral edema, carpal tunnel syndrome, myalgias, and arthralgias

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16
Q

How is IGF-1 deficiency (or a lack of GH receptor)treated?

A

This is a rare disorder that is treated with Mecasermin (Increlex), hIGF-1 only or Mecasermin rinfabate (iPlex), a complex of hIGF-1 and hIGFBP-3 (necessary to produce a longer half-life because children with severe IGF-1 deficiency usually have IGFBP deficiency also)The benefit of iPlex is that there is not the hypoglycemia associated with Increlex but it is more expensive.

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17
Q

How is GH excess treated?

A

Somatostatin analogs are the best treatment when pitutiary surgery is impossible and the most widely used is octreotide (Sandostatin) given as 3 daily injectionsor a long-acting slow release form called Sandostatin-LAR which is injected once every 4 weeksNOTE: Lanreotide (somatuline LA) is now available in the US

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18
Q

AEs of somatostatin analogs?

A

Mostly Gi disturbances including diarrhea, nausea, and abdominal pain

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19
Q

What is the effect of Pegvisomant?

A

It is a GH receptor antagonist that decreases IGF-1used for tx of acromegalyNOTE: PEG is covelantly bound to decrease renal clearnace and extend half-life

20
Q

When do prolactin levels rise in a person?

A

Prolactin rises during pregnancy, remains elevated until birth, and falls thereafter unless the mother breast-feeds.

21
Q

What commonly causes hyperprolactinemia and how would it present?

A

Hyperprolactinemia is most often caused by pituitary adenomas or inhibition of dopamine. This may present as galactorrhea, amenorrhea, and infertility in women and loss of libido, impotence, and infertility in men

22
Q

How is hyperprolactinemia treated?

A

Usually treated by surgery, radiation, or the use of dopamine-receptor agonists (Cabergoline or bromocriptine) that suppress prolactin production through D2 receptors

23
Q

What are some thyrotropin-releasing hormone analogs and their functions?

A

-Protirelin (stimulates TSH release from the pituitary to test thyroid function not Tx)-Thyrotropin alpha hTRH (Thyrogen) (used is diagnostics for thyroglobulin levels)

24
Q

What are the thyroid hormone analogs?

A

Levothyroxine (L-T4) (Synthroid, Levoxyl,Levothroid)Liothyronine sodium (L-T3) (Cytomel tablets, Triostat injectables)Liotrix (mixture of L-T4 and L-T3) (Thyrolar)

25
Q

What are some antithyroid synthesis drugs?

A

Propylthiouracil (PTU)Methimazole (Tapazole)Carbimazole (Neo-mercazole)

26
Q

How does iodine deficiency change the ratio of T4:T3 produced in the thyroid gland?

A

It changes from 4:1 to 1:3

27
Q

Adequate amounts of thyroid hormone are essential for normal fetal brain development. How does the baby get thyroid early in pregnancy?

A

The fetus relies on thyroid from maternal circulation in the first trimester

28
Q

How are thyroid hormones cycled through the body?

A

T3 and T4 are both metabolized in the liver through glucuronide conjugation and sulfate conjugation pathways that allow excretion of these hormones through the bile. Once in the GI, these hormones are subject to enterohepatic cycling because glucuronidases secreted by microorganisms in the lower intestine hydrolyze the glucuronide conjugates and release the free hormones to be reabsorbed.

29
Q

T or F. Thyroxine binding globulin binds T3 more tightly than T4

A

F. It binds T4 more tightly than T3 and in a 1:1 fashion

30
Q

What are some other carriers of thyroid hormones?

A

Transthyretin (TTR) binds 2:1 and also transports T4 in CSFAlbumin binds both T4 and T3

31
Q

When the pituitary reacts to levels of thyroid hormones in the blood, what is it reacting to?

A

Only the amount of ‘free’ or unbound hormone

32
Q

How does thyroid hormone act on target tissue?

A

They (both T4 and T3) bind to nuclear receptors on target tissues, specifically TRa1 receptor proteins, as well as TRB1 and TRB2, that bind to specific DNA sequences called thyroid hormone response elements to increase or decrease DNA transcription (note that while T4 binds to these receptors, only T3 can stimulate transcription).T3 also binds avidly to mitochondrial membranes and activates the mitochondrial adenine nucleotide transporter

33
Q

What are the cardiac effects of thyroid hormone?

A

The CV effects of thyroid can be thought of as a response to increased peripheral oxygen consumption and are designed to get more blood to the periphery. This occurs via increasing HR (tachycardia), stroke volume, inducing cardiac hypertrophy, decreasing peripheral vascular resistance, and increased pulse pressureThis about how hyperthyroidism and hypothyroidism might present on a cardiac exam then

34
Q

What is Grave’s disease? Tx?

A

Condition where autoantibodies directed against TSH receptors on the thyroid gland stimulate increased hormone production and usually requires surgery, radiaoctive iodine, and drugs to treat

35
Q

One drug included for the treated of hyperthyroidism is PTU. How does it work?

A

Propylthiouracil binds to thyroid peroxidase and thereby inhibits the conversion of iodide to iodine. Thyroid peroxidase normally converts iodide to iodine (via hydrogen peroxide as a cofactor) and also catalyzes the incorporation of the resulting iodide molecule onto both the 3 and/or 5 positions of the phenol rings of tyrosines found in thyroglobulin.PTU also acts by inhibiting the enzyme 5’-deiodinase, which converts T4 to T3 in the periphery

36
Q

Another drug for hyperthyroidism is methimazole. How does it work?

A

Methimazole binds to thyroid peroxidase and thereby inhibits the conversion of iodide to iodine.NOTE: Carbimazole is a pro-drug for methimazole

37
Q

Which is more potent, PTU or methimazole?

A

Methimazole is 10x more potent

38
Q

AEs of PTU?

A

The most common side effects are related to the skin, and include rash, itching, hives, abnormal hair loss, and skin pigmentation.-agranulocytosis or thrombocytopenia (common in the first 3 months of treatment)-fulminant liver failure (may occur at any point in treatment)

39
Q

Which hyperthyroid drug is preferred in pregnancy?

A

Propylthiouracil is classified asDrug Class D in pregnancy. Class D signifies there is positive evidence of human fetal risk. Maternal benefit may outweigh fetal risk in life-threatening situations.PTU is preferred overmethimazole(which is also a class D) only in the first trimester of pregnancy and in woman who may become pregnant because of the increased risk of teratogenicity of methimazole during critical organogenesis. In the second and third trimester, this risk is diminished andmethimazoleis preferred to avoid the risk of liver complications from PTU in the mother

40
Q

What happens if PTU crosses the placenta?

A

The primary effect on the fetus from transplacental passage of PTU is the production of a mild hypothyroidism when the drug is used close to term. This usually resolves within a few days without treatment. The hypothyroid state may be observed as a goiter in the newborn, and is the result of increased levels of fetal pituitary thyrotropin.The incidence of fetal goiter after PTU treatment in reported cases is approximately 12%

41
Q

How is Propranolol used to treat hyperthyroidism? Whenis it preferred?

A

Prevents conversion of T4 to T3 and is preferred in some patients such as Graves disease and thyroid storm patients because T3 has potent effects on the heart

42
Q

What are some possible AEs of Iodinated contrast media (which are approved for improved contrast CT scans, cardiac caths, etc.)?

A

Can cause incident hyperthyrodisim in euthyroid pts. OR thyroid storm in hyperthyroid pts.

43
Q

How does large amounts of iodine affect the thyroid gland?

A

It inhibits all aspects of iodine metabolism by the thyroid gland, thus blocking release of thyroid hormone

44
Q

What are some of the treatment uses of iodine?

A

Can be used to treat thyroid storm in some patients and helps to decrease size, vascularity, and fragility of a hyperplastic gland. Thus, iodine is not designed to be a long-term treatment option but is a valuable adjuvant therapy, especially for pre-operative treatment.

45
Q

T or F. Iodine should not be used prior to radioactive iodide treatment

A

T.

46
Q

How is radioactive (Na131I) iodine used?

A

PO drug that concentrates in the thyroid gland, where B-radiation will destroy all or part of the parenchymal cells in several weeks causing hypothyroidism, but not surrounding thyroid tissue.NOTE: There is no evidence of radiation-induced dmaage of other tissues

47
Q

What patients can use radioactive iodine?

A

Adults 35+, but not in women of child-bearing age

STEP Pharm II (42 decks)

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