Thyroid and Anti-Thyroid Agents

  1. What are the two active thyroid hormones?
    Thyroxine (T4) and Triiodothyronine (T3)
  2. What enzyme catalyzes the removal of one iodine from T4 to give T3?
  3. Where does the majority (80%) of T3 come from?
  4. What are 5 actions of TSH?
    • 1. increase blood flow
    • 2. I- uptake
    • 3. T3/T4 synthesis
    • 4. T3/T4 release
    • 5. hypertrophy (goiter)
  5. How do T3/T4 affect growth and development?
    increase protein synthesis
  6. What effect does T3/T4 have on the cardiovascular system?
    increase HR and CO (increase beta adrenoreceptors)
  7. What effect does T3/T4 have on the central nervous system?
    increases activity and awareness
  8. What are the metabolic effects of T3/T4?
    increase CHO metabolism and increase lipolysis
  9. What is the most common etiology of Hypothyroidism?
    Autoimmune thyroiditis (Hashimoto's disease)
  10. What is the name of primary thyroid deficiency in children?
  11. What is the name of primary thyroid deficiency in adults?
  12. What are two causes of cretinism?
    endemic (not enough iodine in diet) and athyrotic (genetic disorder)
  13. What are the four treatment options for hypothyroidism?
    • Thyroid powder
    • Levothyroxine sodium (T4)
    • Liothyronine sodium (T3)
    • Liotrix (T4:T3 / 4:1)
  14. What would you administer to treat an emergency case of hypothyroidism?
    liothyronine sodium (T3)
  15. When treating hypothyroidism, patients with what diease should you be cautious of?
    cardiovascular disease
  16. What side effects do hypothroidism treatments have on the CNS, cardiovascular system, and metabolic rate?
    • CNS: nervousness, insomnia, increase activity
    • CV: hypertension, cardiac dysrhythmias
    • Metabolic: increase BMR
  17. What are 3 thiourylenes?
    • Propylthiouracil (PTU)
    • Methimazole
    • Carbimazole (not used in US)
  18. What do thiourylenes treat?
  19. What is the mechanism of action for thiourylenes?
    block activity of peroxidase enzyme
  20. What are 5 side effects of thiourylenes?
    • rash
    • nausea
    • headahce
    • joint pain
    • agranulocytosis
  21. Which thiourylene has less compliance with patients?
    Propylthiouracil (PTU) due to its shorter half-life (2 hours)
  22. What are 5 treatment options for hyperthyroidism and/or its symptoms?
    • thiourylenes
    • radioactive iodine
    • thyroidectomy
    • iodide
    • beta-adrenorecptor antagonsists (propranolol)
  23. What are adverse effects to a thyroidectomoy?
    • hypothyroidism
    • hypoparathyroidism
  24. Why are antithyroid agents not the best option for treatment of hyperthyroidism?
    they can lose their effectiveness over time
  25. Which isotope of iodine is used in radioactive iodine treatment of hyperthyroidism?
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Thyroid and Anti-Thyroid Agents
Thyroid and Anti-Thyroid Agents - Kasson