Pharmacology of Thyroid Hormone
29 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary use of levothyroxine sodium?

  • Induction of remission in Graves' disease
  • Management of goiter
  • Treatment of hyperthyroidism
  • Thyroid hormone replacement in hypothyroidism (correct)

    • Which of the following is NOT a thioamide drug?

  • Methimazole
  • Propylthiouracil
  • Carbimazole
  • Levothyroxine (correct)

    • What is the recommended initial dose for elderly patients receiving thyroid hormone therapy?

  • High initial dose
  • Standard adult dose
  • No dose adjustments needed
  • Low initial dose with slow increase (correct)

    • What condition may result from excessive thyroid hormone levels?

    <p>Thyrotoxicosis</p> Signup and view all the answers

    Which medication is considered safe for use during pregnancy and lactation?

    <p>Propylthiouracil</p> Signup and view all the answers

    Which of these is a common adverse effect of thioamide drugs?

    <p>Agranulocytosis</p> Signup and view all the answers

    What is one of the primary uses of β-adrenoceptor antagonists like Propranolol?

    <p>To reduce cardiovascular stimulation associated with hyperthyroidism</p> Signup and view all the answers

    What is the half-life of T4 (levothyroxine) compared to T3 (liothyronine)?

    <p>T4 has a half-life of one week, T3 has 2 days</p> Signup and view all the answers

    Which of the following is a type of iodide salt used in thyroid crisis?

    <p>Lugol solution</p> Signup and view all the answers

    Which treatment option is commonly used for hyperthyroidism?

    <p>Surgical removal of the thyroid gland</p> Signup and view all the answers

    What is the mechanism of action for radioactive iodine (I-131) in treating thyroid conditions?

    <p>It emits β-particles that destroy thyroid tissue.</p> Signup and view all the answers

    How long does it generally take for the maximum effect of iodide salts to manifest?

    <p>10-15 days</p> Signup and view all the answers

    Which of the following conditions is characterized by abnormal mineralization of new bone matrix?

    <p>Osteomalacia</p> Signup and view all the answers

    What contraindicates the use of radioactive iodine in treatment?

    <p>Pregnancy and lactation</p> Signup and view all the answers

    Which of the following correctly describes osteoporosis?

    <p>A gradual reduction in bone mass leading to fractures</p> Signup and view all the answers

    What is the half-life of radioactive iodine (I-131) after administration?

    <p>8 days</p> Signup and view all the answers

    What effect does Raloxifene have on postmenopausal women?

    <p>Increases bone density and decreases vertebral fractures</p> Signup and view all the answers

    How is Denosumab administered?

    <p>Subcutaneously once every 6 months</p> Signup and view all the answers

    What is the primary clinical use of Calcitonin?

    <p>To inhibit osteoclast activity and decrease bone turnover</p> Signup and view all the answers

    What is a unique characteristic of Teriparatide?

    <p>It is a recombinant form of human PTH</p> Signup and view all the answers

    How does Strontium ranelate function in the prevention of osteoporosis?

    <p>By decreasing osteoclastic activity and reducing bone resorption</p> Signup and view all the answers

    What is rickets primarily caused by in children?

    <p>Vitamin D deficiency</p> Signup and view all the answers

    Which of the following groups is particularly at risk for osteomalacia due to impaired vitamin D absorption?

    <p>Adults with chronic renal impairment</p> Signup and view all the answers

    What is the primary mechanism of action of bisphosphonate drugs?

    <p>Inhibit bone resorption</p> Signup and view all the answers

    Which of the following is an example of a third-generation bisphosphonate?

    <p>Ibandronate</p> Signup and view all the answers

    Estrogen helps to manage bone health by affecting which type of cells?

    <p>Osteoclasts</p> Signup and view all the answers

    Which of the following medications is indicated for the prevention and treatment of osteoporosis in postmenopausal women?

    <p>Ibandronate</p> Signup and view all the answers

    What role do oral calcium and vitamin D supplements play in bone health?

    <p>They are essential for optimal bone formation</p> Signup and view all the answers

    Which compound is known to inhibit bone resorption while also stimulating bone formation?

    <p>Strontium</p> Signup and view all the answers

    Study Notes

    Pharmacology of Thyroid Hormone

    • Thyroid hormone synthesis: Thyroid cells take up iodine and couple it with tyrosine residues in thyroglobulin. This creates thyroxine (T4) and triiodothyronine (T3).

    • Hyposecretion (Hypothyroidism): Thyroid replacement therapy includes levothyroxine sodium (T4), typically more effective than liothyronine sodium (T3) in suppressing TSH.

    • Hypersecretion (Hyperthyroidism): Treatments include antithyroid drugs, irradiation, or surgical removal of the overactive tissue.

    Thyroid Hormone Preparations

    • Levothyroxine and Liothyronine: Synthetic thyroid hormones used for replacement therapy. A mixture containing T4 and T3 in a 4:1 ratio (liotirix) is also available. Levothyroxine is the typical drug of choice for hypothyroidism.

    • Pharmacokinetics: T4 and T3 have good absorption and are adequately absorbed orally. T4 has a longer half-life (one week) compared to T3 (two days).

    Antithyroid Agents

    • Thioamide drugs: Carbimazole, methimazole, and propylthiouracil (PTU). PTU is often preferred during pregnancy and lactation.

    • Indicate use : used to treat Graves' disease & suppress symptoms before surgery or radioactive iodine treatment.

    • Pharmacokinetics Given orally; carbimazole is metabolized to methimazole.

    Other Anti-thyroid Agents

    • Beta-adrenergic antagonists: Like propranolol, reduce the cardiovascular effects of hyperthyroidism (e.g., anxiety).

    • Iodide salts: Immediate effects on thyroid hormone release, used in thyroid storm (acute thyrotoxicosis) and short-term treatment.

    Radioactive Iodine

    • Mechanism: Absorbed rapidly by the thyroid and emits beta particles to destroy thyroid tissue.

    • Uses: Definitive treatment for relapses of Graves' disease, toxic multinodular goiter and toxic solitary nodule.

    • Contraindications: Pregnancy and lactation.

    Bone Disorders

    • Osteoporosis: Reduced bone mass, leading to easy fractures. Common in postmenopausal women.

    • Osteomalacia: Abnormal bone mineralization, often caused by vitamin D deficiency. Similar in children, results in rickets.

    Drugs Affecting Calcium and Bone

    • Cinacalcet: Activates calcium sensing receptors, lowering parathyroid hormone levels, reducing calcium levels.

    • Calcitonin: Decreases calcium excretion by the kidneys and calcium absorption in the intestines; used for managing hypercalcemia and osteoporosis.

    • Vitamin D: A crucial nutrient for calcium regulation; its activation converts vitamin D to its active form (calcitriol).

    • Diet is an important preventative measure in maintaining a balance of bone health.

    Drug Treatment of Bone Loss

    • Bisphosphonates: Inhibit bone resorption, commonly used in osteoporosis prevention and treatment.

    Strontium Ranelate

    • Usage: Indicated for prevention and treatment of osteoporosis in postmenopausal women.

    • Mechanism: Decreases osteoclastic activity and increases bone formation.

    Sodium Fluoride

    • Mechanism: Replaces hydroxyl groups in bone, to form fluorapatite, which is more resistant to erosion than hydroxyapatite.

    • Usage: Prevents dental caries and tooth decay.

    Denosumab

    • Mechanism: Inhibits osteoclast activity, reducing bone resorption.

    • Usage: Treats osteoporosis

    Teriparatide

    • Mechanism: Newer drug, a type of parathyroid hormone.

    • Usage: Treats osteoporosis.

    Calcium and Vitamin D

    • Adequate intake: Critical for bone health in children and adults to prevent osteoporosis, primarily by consuming dairy products and taking supplements when necessary,

    • Potential issues: Aging, malabsorption issues or certain medications can disrupt vitamin D metabolism, leading to bone-related issues.

    Iron-Deficiency and Anemia

    • Iron-deficiency Anemia (IDA): Results from insufficient iron uptake.

    • Anemia of Inflammation (AI/ACD): Associated with chronic inflammation or disease.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Pharmacology Of Thyroid Hormone 2024-2025 PDF

    Description

    Test your knowledge on the pharmacology of thyroid hormones, including their synthesis, effects of hypo- and hypersecretion, and treatments available. Learn about thyroid hormone preparations and the role of antithyroid agents in managing thyroid conditions.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser