Repro-Endo: Thyroid / Parathyroid Flashcards Preview

Pharmacology > Repro-Endo: Thyroid / Parathyroid > Flashcards

Flashcards in Repro-Endo: Thyroid / Parathyroid Deck (29)
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1

Levothyroxine / Triiodothyronine

  • T4 analog (Thyroxine replacement) / T3 analog
  • Binds to nuclear receptors
  • Increased Protein synthesis and Metabolic rate
  • Increased Beta-receptor Increased sensitivity to Catecholamines
  • Tx: Hypothyroidism / Myxedema
  • SE: Hyperthyroidism (Tachy, Heart failure, Sweating, Tremor, Arrhythmias, Diarrhea)

2

Methimazole, Propylthiouracil (PTU)

  • Thionamides
  • Inhibits Thyroid Peroxidase --> Blocking Synthesis
  • Propylthiouracil (PTU) also inhibits Peripheral conversion of T4 --> T3 by blocking 5'-deiodinase
  • PTU avoided as first line treatment
  • PTU used during First Trimester in pregnancy (Teratogenic effects)
  • Tx: Hyperthyroidism, 3 Ps of PTU
  • SE: Rash, Urticaria, Fever, Nausea, Agranulocytosis, Thrombocytopenia, Acute Hepatic necrosis, Vasculitis, Hepatotoxicity (Propylthiouracil) Possible Teratogen (Methimazole)

3

Iodine and Radioiodine

  • Inhibits Thyroid Hormone release
  • 131I concentrated in the Thyroid gland and emits Beta and Gamma XRT
  • Drug of choice for destroying Toxic Adenoma
  • NEVER USE w/ Pregnant women
  • Tx: Thyroid Storm and Before Thyroidectome (prevents Thyroid Storm), Hyperthyroidism, Adjunctive Tx for some Thyroid cancers
  • SE: Dysgeusia (metalic taste), Excessive salvation, Diarrhea, Rash

4

Bisphosphonates

(Alendronate)

  • Stabilizes bony matrix
  • Coats hydroxyapatite to prevent Osteoclasts from Resorbing bone
  • Tx: Postmenopausal Osteoporosis, Paget disease
  • SE: Heartburn, Erosive esophagitis, Stomach upset, Joint/Back pain, Osteonecrosis of the Jaw

5

Calcitonin

  • Lowers Serum Calcium
  • Mild analgesic properties for Bone pain
  • Intranasal / Subcutaneous
  • Tx: Hypercalcemic states
  • SE: Runny nose, and Nasal discomfort, Flushing

6

Calcitriol

  • Activated form of Vitamin D
  • Increases Calcium absorption from Intestines
  • Tx: Hypocalcemia, Vit. D replacement in Pts. w/ End-Stage Renal Disease
  • SE: Vit. D. Intoxication: Hypercalcemia, Polyuria, Weakness, Headache, Somnolence, and Constipation

7

Rx for Hypothyroidism?

Levothyroxine (T4)

8

Rx for Hyperthyroidism?

1st: Methimazole

2nd: PTU (Propylthiouracil)

Pregnancy: 1st Trimester = PTU, 2nd - 3rd = Methimazole

9

Rx for Thyroid Storm?

131I or Radioiodine

10

Rx for Postmenopausal Osteoporosis?

Bisphosphonates

(Alendronate)

11

Rx for Paget Disease to reduce bone turnover?

Bisphosphonates

(Alendronate)

12

Rx for Hypercalcemic states?

Calcitonin

MISHAP

  • Malignancy
  • Intoxication w/ Vit. D
  • Sarcoidosis
  • Hyperparathyroidism
  • Alkali (Mikl-alkali syndrome)
  • Paget Disease

13

Rx for Hypocalcemia?

Calcitriol

14

Rx for End-Stage Renal Disease?

Calcitriol

15

Thyroglobulin

  • Rx for Hypothyroidism
  • Potency of each preparation varies
  • Thyroglobulin is a protein produced by thyroid cells (both normal and cancerous cells). After removal of the thyroid gland, Thyroglobulin can be used as a "cancer marker."

16

Sodium Liothyronine

  • Tx for Hypothyroidism
  • Short acting w/ Rapid onset
  • A synthetic form of natural T3 hormone with same actions as natural product; thyroid hormone raises basal metabolic rate, increases utilization and mobilization of glycogen store, and promotes gluconeogenesis
  • Tx: Hypothyroidism, Nontoxic goiter, Myxedema, Myxedema coma

17

Lugol's Solution

(KI and I2)

  • a solution of elemental iodine and potassium iodide in water
  • It was also used at one time as a first line treatment for Hyperthyroidism, as the administration of pharmacologic amounts of iodine leads to temporary inhibition of iodine organification in the thyroid gland, a phenomenon called the Wolff-Chaikoff effect.

18

Mechanism of PTH?

  • PTH increases plasma Ca2+
  • Stimulates adenylyl cyclase in target tissues
  • Elevated cAMP inhances syn. of 1,25(OH)2D3
  • Increasing bone resorption by activating Osteoblast --> Osteoclast and Stimulating Ca2+ transport from bone to extracellular fluids
  • Increases the synthesis of 1,25(OH)2D3 at the lvl of the Kidney
  • Increases Renal tubular reabsorption of Ca2+

19

Mechanism of 1,25(OH)2D3

  • 1,25 dihydroxycholecalciferol
  • 7 dehydrocholesterol is converted to Cholecalciferol (D3) by UV light at the skin
  • D3 is converted to 25(OH)D3 in the Liver
  •  25(OH)D3 converted to 1,25(OH)2D3 (calcitriol) in the Kidney
  • PTH stimulates 1α-hydroxylase, is the Kidney's converting enzyme.
  • Increases plasma Ca2+
  • Increasing the synthesis of Ca2+ binding transport protein in the Mucosal cells of the gut --> Increaseing absorption
  • Increasing Ca2+ transport from Bone to Extracellular fluids (in large doses)

20

Mechanism of Calcitonin?

  • Decreases plasma Ca2+
  • Decreasing bone reabsorption by inhibiting activity of osteoclasts
  • Decreasing tubular reabsortpion of Ca2+

21

Rx for Hypoparathyrodism?

  • Hypocalcemia
  • Hyperphosphatemia
  • Tx: Dietary calcium and 1,25(OH)2D3 
  • PTH and Calcium gluconate mabe be used following surgical parathyroidectomy to prevent Hypocalemic tetany

22

Rx for Pseudohypoparathyrodism?

  • PTH lvls are Normal or Elevated
  • Serum Ca2+ is low
  • End organs are insensitive to PTH
  • Often abnormal Gs, the transducer that links PTH receptor to Adenylyl cyclase
  • Tx: 1,25(OH)2D3 can correct Hypocalcemia, but it does not always improve Bone disease

23

Rx for Rickets and Osteomalacia?

  • Inadequate miniralization of Bone matrix
  • Lack of exposure to sunlight, resulting in impaired vitamin D3 synthesis in the skin
  • Supplementing food and Vit. D2 has greatly reduced the incidence
  • Tx: Administer Vit. D2 or D3

24

Rx for Vit. D-dependent Rickets?

  • Autosomal recessive does not respond to Vit. D admin.
  • Defect belived to be in the 1α-hydroxylase enzyme w/in the Kidney
  • Tx: 1,25(OH)2D3

25

Rx for Drug-induced Osteopenia?

  • The anticonvulsant drugs, Phenytoin, Phenobarbital, and Corticosteroids, suppress intestinal Ca2+ absorption w/ Secondary Hyperparathyroidism (elevated PTH)
  • High doses of corticosteroids inhibit Osteoblast diff. and Collagen syn. --> decreased bone mass
  • Tx: 25(OH)D3, D2, or D3 improve symptoms of Anticonvulsant-induced Osteomalacia (Osteopenia)

26

Rx for Paget's Disease?

  • Overactive Osteoclast activity in bone resulting in Deminieralization of Osteoid tissue
  • Painful, Multiple bone compression fractures
  • Tx: Calcitonin via Nasal spray, Sodium Etidronate (bisphosphonate), also Alendronate and Risedronate, and even Ibandronate.

27

Rx for Postmenopausal Osteoporosis?

  • Abnormal, rapid loss of bone, predisposing postmenopausal women to Fracture
  • Tx: Estrogen replacement therapy w/ increased risk of Heart disease, Breast cancer, and Uterine cancer w/ HRT
    • SERM - Raloxifene is safer
  • Bisphosphonates: Alendronate, Risedronate, Ibandromate, or Zoledronic acid
  • Teriparatide (Human PTH1-34) is effective for treating osteoporosis --> stimulates new bone growth and reduces vertebral fracture risk by 65%, injected daily

28

Rx for Vitamin D intoxication?

  • Hypercalcemia leading to Ca2+ deposition in soft tissues
  • Tx: Stop Vit. D administration, Administer Glucocorticoids, such as Prednisone --> Block GI absorption of Ca2+

29

Rx Primary Hyperparathyroidism?

  • Commonly Adenoma
  • Severe Hypercalcemia, Hypophosphatemia, Prominent bone resoprtion, Soft Tissue calcification, Elevated 1,25(OH)2D3 and Nephrolithiasis
  • Tx: Surgical removal of Adenoma