Thyroid Hormone Replacement Therapy Quiz
49 Questions
1 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

Which thyroid hormone replacement has a shorter half-life?

  • Neither has a half-life
  • Both have the same half-life
  • L-thyroxine (LEVOTHYROXINE)
  • Liothyronine (T3) (correct)

    • What is the standard dose range for L-thyroxine (LEVOTHYROXINE) tablets?

  • 100-125 µg per day
  • 12.5-25 µg per day
  • 50-150 µg per day (correct)
  • 1.6 µg per Kg body weight per day

    • Which thyroid hormone replacement is cautioned in elderly and known ischaemic heart disease?

  • L-thyroxine (LEVOTHYROXINE) (correct)
  • Both are cautioned
  • Neither is cautioned
  • Liothyronine (T3)

    • Which thyroid hormone replacement is used intravenously for myxoedema coma?

    <p>Liothyronine (T3)</p> Signup and view all the answers

    Which of the following factors can reduce the absorption of L-thyroxine (LEVOTHYROXINE)?

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

    What is the half-life of L-thyroxine (LEVOTHYROXINE)?

    <p>6-8 days</p> Signup and view all the answers

    How long does it take for symptoms to improve after starting L-thyroxine (LEVOTHYROXINE) treatment?

    <p>2-4 weeks</p> Signup and view all the answers

    What are the special situations where the dose of L-thyroxine (LEVOTHYROXINE) may need to be adjusted?

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

    Which medications can accelerate the metabolism of L-thyroxine and Liothyronine?

    <p>Rifampicin, phenytoin, carbamazepine</p> Signup and view all the answers

    Which medication can potentiate the effects of L-thyroxine and Liothyronine?

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

    What is the recommended treatment for overdose of L-thyroxine and Liothyronine?

    <p>Beta-blocker (deiodinase inhibitor)</p> Signup and view all the answers

    Which condition is characterized by mental retardation, growth restriction, and spastic diplegia?

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

    What is the cause of endemic goiter?

    <p>Iodine deficiency</p> Signup and view all the answers

    What is the prevalence of sporadic congenital hypothyroidism?

    <p>1 in 2000 live births</p> Signup and view all the answers

    Which of the following is the primary source of iodine intake?

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

    What is the recommended daily intake of iodine according to WHO?

    <p>150µg/day</p> Signup and view all the answers

    In which situation is a higher intake of iodine required?

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

    Which type of anti-thyroid drug inhibits iodide uptake into the thyroid gland follicular cell?

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

    Which type of anti-thyroid drug inhibits organification and hormone release?

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

    Which type of anti-thyroid drug inhibits peripheral thyroid hormone metabolism?

    <p>Beta-blockers</p> Signup and view all the answers

    Which of the following is the mechanism of action of thionamides?

    <p>Inhibition of oxidation and organification of iodine</p> Signup and view all the answers

    What is the clinical use of thionamides?

    <p>Treatment of Graves' disease</p> Signup and view all the answers

    What is the maximum effect of thionamides?

    <p>Delayed effect</p> Signup and view all the answers

    Which thionamide has a longer half-life?

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

    Which thionamide is preferred during pregnancy?

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

    Which thionamide has an additional pharmacological property of inhibiting peripheral T4 to T3 conversion?

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

    Which thionamide accumulates in the thyroid?

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

    Which thionamide is primarily metabolized in the thyroid and elsewhere?

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

    Which of the following is the most serious side effect of thionamides?

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

    Which side effect of thionamides is commonly seen?

    <p>Skin rashes and pruritus</p> Signup and view all the answers

    What is the management for neutropenia and agranulocytosis caused by thionamides?

    <p>All of the above</p> Signup and view all the answers

    Which thionamide crosses the placenta and can cause fetal hypothyroidism and goiter?

    <p>Both carbimazole/methimazole and PTU</p> Signup and view all the answers

    Which treatment is considered the best for nodular thyrotoxicosis?

    <p>Radioactive Iodine</p> Signup and view all the answers

    What is the half-life of radioactive iodine?

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

    What is the main action of radioactive iodine on the thyroid follicles?

    <p>Cytotoxic action</p> Signup and view all the answers

    What is the risk of hypothyroidism after treatment with radioactive iodine?

    <p>25-50%</p> Signup and view all the answers

    Which statement about iodide's effect on thyroid hormone synthesis and secretion is correct?

    <p>Iodide transiently inhibits thyroid hormone synthesis and secretion.</p> Signup and view all the answers

    What is the effect of iodide on the conversion of iodide to organic iodine?

    <p>Iodide inhibits the conversion of iodide to organic iodine.</p> Signup and view all the answers

    What is the effect of iodide on thyroid hormone release?

    <p>Iodide inhibits thyroid hormone release.</p> Signup and view all the answers

    What is the effect of iodide on the vascularity of the thyroid gland?

    <p>Iodide decreases the vascularity of the thyroid gland.</p> Signup and view all the answers

    Which of the following is the main mechanism of action of Propranolol?

    <p>Inhibits peripheral conversion of T4 to T3</p> Signup and view all the answers

    What is the primary use of Propranolol?

    <p>To block symptoms of sympathetic overactivity</p> Signup and view all the answers

    Which of the following is a characteristic of Propranolol's pharmacokinetics?

    <p>Poor oral bioavailability due to first-pass hepatic metabolism</p> Signup and view all the answers

    Which adverse effect is associated with Propranolol's action on bronchial B2-receptors?

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

    Which of the following is NOT an adverse effect of Propranolol?

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

    Which condition is a contraindication for the use of Propranolol?

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

    Which of the following is a characteristic of cardioselective beta-adrenoceptor blockers?

    <p>Water soluble</p> Signup and view all the answers

    Which adverse effect is NOT associated with cardioselective beta-adrenoceptor blockers?

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

    Which condition is NOT an indication for using cardioselective beta-adrenoceptor blockers?

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

    Study Notes

    Thyroid Hormone Replacement

    • Triiodothyronine (T3) has a shorter half-life compared to thyroxine (T4).
    • The standard dose range for L-thyroxine (LEVOTHYROXINE) tablets is 50-200 mcg/day.
    • L-thyroxine is cautioned in elderly patients with known ischaemic heart disease.
    • Triiodothyronine (T3) is used intravenously for myxoedema coma.

    Absorption and Half-Life of L-Thyroxine

    • Factors that can reduce the absorption of L-thyroxine include iron, calcium, and soy products.
    • The half-life of L-thyroxine is 1-2 days.
    • Symptoms of hypothyroidism improve within 1-2 weeks after starting L-thyroxine treatment.

    Special Situations and Interactions

    • The dose of L-thyroxine may need to be adjusted in special situations such as pregnancy, lactation, and cardiac disease.
    • Medications that can accelerate the metabolism of L-thyroxine and Liothyronine include phenytoin, carbamazepine, and rifampin.
    • Medications that can potentiate the effects of L-thyroxine and Liothyronine include warfarin and insulin.
    • The recommended treatment for overdose of L-thyroxine and Liothyronine is supportive care.

    Congenital Hypothyroidism and Iodine Intake

    • Cretenism is characterized by mental retardation, growth restriction, and spastic diplegia.
    • The cause of endemic goiter is iodine deficiency.
    • The prevalence of sporadic congenital hypothyroidism is 1 in 3,000-4,000 births.
    • The primary source of iodine intake is iodized salt.
    • The recommended daily intake of iodine according to WHO is 150 mcg/day.
    • A higher intake of iodine is required in pregnancy and lactation.

    Anti-Thyroid Drugs

    • Thionamides, such as methimazole and carbimazole, inhibit iodide uptake into the thyroid gland follicular cell.
    • Thionamides also inhibit organification and hormone release, and peripheral thyroid hormone metabolism.
    • The mechanism of action of thionamides is the inhibition of thyroid hormone synthesis.
    • The clinical use of thionamides is in the treatment of hyperthyroidism.
    • The maximum effect of thionamides is seen after 1-2 weeks of treatment.
    • Methimazole has a shorter half-life compared to carbimazole.
    • Carbimazole is preferred during pregnancy.
    • Methimazole has an additional pharmacological property of inhibiting peripheral T4 to T3 conversion.
    • Carbimazole accumulates in the thyroid and is primarily metabolized in the thyroid and elsewhere.
    • The most serious side effect of thionamides is agranulocytosis.
    • Common side effects of thionamides include rash, pruritus, and arthralgia.
    • Neutropenia and agranulocytosis caused by thionamides should be managed with prompt withdrawal of the drug and supportive care.

    Radioactive Iodine

    • Radioactive iodine is used in the treatment of nodular thyrotoxicosis.
    • The half-life of radioactive iodine is 8 days.
    • Radioactive iodine destroys thyroid follicles, reducing thyroid hormone production.
    • The risk of hypothyroidism after treatment with radioactive iodine is high.

    Iodide's Effects on Thyroid Hormone Synthesis and Secretion

    • Iodide inhibits the conversion of iodide to organic iodine, reducing thyroid hormone synthesis.
    • High doses of iodide inhibit thyroid hormone release.
    • Iodide decreases the vascularity of the thyroid gland.

    Propranolol

    • The main mechanism of action of Propranolol is the blockade of beta-adrenoceptors.
    • The primary use of Propranolol is in the treatment of thyrotoxic crisis.
    • Propranolol has a short half-life of 3-6 hours.
    • Propranolol can aggravate bronchial asthma due to its action on bronchial B2-receptors.
    • The main adverse effect of Propranolol is bradycardia.
    • Contraindications for the use of Propranolol include heart failure and asthma.

    Cardioselective Beta-Adrenoceptor Blockers

    • Cardioselective beta-adrenoceptor blockers have a higher affinity for beta1-receptors.
    • Cardioselective beta-adrenoceptor blockers do not cause bronchospasm.
    • Indications for the use of cardioselective beta-adrenoceptor blockers include hypertension, angina, and heart failure.

    Studying That Suits You

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

    Quiz Team

    Description

    Test your knowledge on thyroid hormone replacement therapy with this quiz. Learn about the different types of thyroid hormones and their dosages, as well as important considerations for specific patient populations.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser