Thyroid Hormones Pharmacology: Learn About Thyroid Hormone Mechanisms and Uses

Question 1

Which of the following is a primary therapeutic use of levothyroxine?

Accepted Answer

Treating hypothyroidism

Answer

Treating hyperthyroidism

Answer

Treating cretinism

Answer

Treating Graves' disease

Question 2

Compared to levothyroxine, liothyronine is:

Accepted Answer

More potent

Answer

Less potent

Answer

Equally potent

Answer

Not used clinically

Question 3

The thyroid gland is located in the:

Accepted Answer

Anterior neck

Answer

Posterior neck

Answer

Thoracic cavity

Answer

Abdominal cavity

Question 4

Which form of thyroid hormone is the **most potent** and has a **shorter half-life**?

Accepted Answer

Liothyronine

Answer

Levothyroxine

Answer

Thyroxine

Answer

Triiodothyronine

Question 5

Which of the following is a common **adverse effect** of thyroid hormone therapy?

Accepted Answer

Tachycardia

Answer

Weight gain

Answer

Lethargy

Answer

Hypothermia

Question 6

In the treatment of hypothyroidism, which of the following is the **preferred route of administration** for thyroid hormones?

Accepted Answer

Oral

Answer

Intravenous

Answer

Intramuscular

Answer

Subcutaneous

Question 7

Which of the following mechanisms of action is **not** involved in the effects of thyroid hormones?

Accepted Answer

Inhibition of oxidative phosphorylation

Answer

Binding to thyroid hormone receptors

Answer

Altering gene expression

Answer

Stimulating the sodium-potassium pump

Question 8

Which of the following laboratory tests is most useful in **monitoring thyroid hormone therapy**?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Answer

Free thyroxine (FT4)

Answer

Total thyroxine (TT4)

Answer

Triiodothyronine (T3)

Question 9

The primary mechanism of action of levothyroxine is through:

Accepted Answer

Binding to nuclear receptors and regulating gene expression

Answer

Inhibiting iodine uptake by the thyroid gland

Answer

Stimulating the production of thyroid-stimulating hormone (TSH)

Answer

Increasing the metabolic rate through lipolysis

Question 10

Which of the following is a common adverse effect of thyroid hormone therapy?

Accepted Answer

Cardiac arrhythmias

Answer

Weight gain

Answer

Menstrual irregularities

Answer

Osteoporosis

Question 11

Which of the following laboratory tests is primarily used to monitor thyroid hormone therapy?

Accepted Answer

Thyroid-stimulating hormone (TSH) level

Answer

Free thyroxine (T4) level

Answer

Thyroglobulin antibody test

Answer

Radioactive iodine uptake scan

Question 12

Which of the following drugs can potentially interfere with thyroid hormone metabolism?

Accepted Answer

Amiodarone

Answer

Warfarin

Answer

Aspirin

Answer

Metformin

Question 13

Which of the following is a therapeutic use of levothyroxine?

Accepted Answer

Replacement therapy for hypothyroidism

Answer

Treatment of hyperthyroidism

Answer

Prevention of thyroid cancer

Answer

Treatment of Graves' disease

Question 14

To which class of pharmacological agents do thyroid hormones belong?

Accepted Answer

Hormones

Answer

Steroids

Answer

Vitamins

Question 15

Which of the following is NOT a mechanism of action of thyroid hormones?

Accepted Answer

Inhibits protein synthesis

Answer

Stimulates lipolysis

Answer

Increases oxygen consumption

Question 16

What is the most commonly used synthetic thyroid hormone in the treatment of hypothyroidism?

Accepted Answer

Levothyroxine

Answer

Thyroglobulin

Answer

Liothyronine

Answer

Calcitonin

Question 17

Which condition is an indication for the use of thyroid hormones?

Accepted Answer

Hypothyroidism

Answer

Graves' disease

Answer

Thyroid cancer

Answer

Hyperthyroidism

Question 18

Which drug can interfere with the absorption of levothyroxine?

Accepted Answer

Sucralfate

Answer

Warfarin

Answer

Atenolol

Answer

Digoxin

Question 19

What is the most common cause of thyrotoxicosis?

Accepted Answer

Graves' disease

Answer

Iatrogenic

Answer

Thyroiditis

Answer

Toxic adenoma

Question 20

Which is NOT a clinical manifestation of thyrotoxicosis?

Accepted Answer

Weight gain

Answer

Tremor

Answer

Goiter

Answer

Tachycardia

Question 21

What is the first-line treatment for Graves' disease?

Accepted Answer

Antithyroid drugs

Answer

Surgery

Answer

Beta-blockers

Answer

Radioactive iodine

Question 22

Which of the following statements accurately describes the mechanism of action of levothyroxine?

Accepted Answer

Levothyroxine is a synthetic T4 hormone that is converted to T3 in peripheral tissues, where it exerts its effects by binding to thyroid hormone receptors and regulating gene transcription.

Answer

Levothyroxine stimulates the thyroid gland to produce more thyroid hormones.

Answer

Levothyroxine directly binds to nuclear receptors and activates gene transcription.

Question 23

A patient with hypothyroidism is prescribed levothyroxine. What is the most likely rationale for monitoring their TSH levels during therapy?

Accepted Answer

To ensure adequate replacement therapy is provided and avoid overtreatment, as TSH levels reflect the body's thyroid hormone status.

Answer

To assess the patient's response to levothyroxine treatment.

Answer

To monitor for potential adverse effects of levothyroxine.

Question 24

A patient with hyperthyroidism is prescribed propylthiouracil (PTU). What is the primary mechanism of action of PTU?

Accepted Answer

PTU inhibits the enzyme thyroid peroxidase, which is essential for the synthesis of thyroid hormones (T3 and T4).

Answer

PTU blocks the binding of T3 and T4 to their receptors.

Answer

PTU stimulates the thyroid gland to release more thyroid hormones.

Question 25

Which of the following is a common adverse effect associated with long-term levothyroxine therapy?

Accepted Answer

Osteoporosis

Answer

Hypoglycemia

Answer

Bradycardia

Answer

Hypotension

Question 26

A patient with Hashimoto's thyroiditis is being treated with levothyroxine. What is the most likely reason for the patient's condition?

Accepted Answer

Hashimoto's thyroiditis is an autoimmune disorder in which the body produces antibodies that attack and destroy thyroid tissue, leading to hypothyroidism.

Answer

Iodine deficiency.

Answer

Pituitary gland dysfunction.

Answer

Exposure to radiation.

Question 27

Which of the following conditions is a contraindication for the use of thyroid hormone therapy?

Accepted Answer

Uncontrolled angina pectoris

Answer

Hypokalemia

Answer

Iron deficiency anemia

Answer

Hypoglycemia

Question 28

A patient with Graves' disease is being treated with radioactive iodine therapy. What is the primary mechanism of action of this treatment?

Accepted Answer

Radioactive iodine is taken up by thyroid cells and emits radiation, leading to the destruction of thyroid tissue and a reduction in hormone production.

Answer

Radioactive iodine stimulates thyroid hormone release.

Answer

Radioactive iodine suppresses thyroid hormone synthesis.

Answer

Radioactive iodine blocks the binding of T3 and T4 to their receptors.

Question 29

Which of the following is a common symptom of hypothyroidism?

Accepted Answer

Weight gain

Answer

Heat intolerance

Answer

Tachycardia

Question 30

Which of the following is a true statement about liothyronine?

Accepted Answer

Liothyronine is a synthetic T3 hormone that has a shorter half-life (24 hours) than levothyroxine (7 days) and a more rapid onset of action.

Answer

Liothyronine has a slower onset of action than levothyroxine.

Answer

Liothyronine is typically used as first-line therapy for hypothyroidism.