Endocrine Pharmacology Practice Questions

Q: Which drug is primarily used to promote fetal lung maturity?

Dexamethasone. ***Dexamethasone*** - **Dexamethasone** is a synthetic glucocorticoid that rapidly crosses the placenta and stimulates the maturation of fetal lung surfactant production. - It significantly reduces the incidence and severity of **respiratory distress syndrome (RDS)** in preterm infants when administered to the mother. - **Antenatal corticosteroids** (dexamethasone or betamethasone) are given to mothers at risk of preterm delivery between 24-34 weeks of gestation. *Folic acid* - **Folic acid** is a B vitamin crucial for cell growth and DNA synthesis, primarily used to prevent **neural tube defects** in developing fetuses. - It does not have a direct role in promoting fetal lung maturity or surfactant production. *Beclomethasone* - **Beclomethasone** is an inhaled corticosteroid primarily used for the long-term management of **asthma** in children and adults. - While it is a corticosteroid, it is not typically used for systemic administration to the mother to promote fetal lung maturity due to its primary delivery method (inhalation) and limited systemic bioavailability compared to dexamethasone or betamethasone.

Q: Which of the following is glucocorticoid synthesis inhibitor?

Metyrapone. ***Metyrapone*** - **Metyrapone** inhibits **11-beta-hydroxylase**, an enzyme essential for the final step in cortisol and corticosterone synthesis in the adrenal cortex [2]. - This inhibition leads to a decrease in **cortisol production** and an increase in upstream steroid precursors like 11-deoxycortisol [2]. *Mifepristone* - **Mifepristone** is a **progesterone receptor antagonist** and, at higher doses, a **glucocorticoid receptor antagonist** [1]. - It does not inhibit the synthesis of glucocorticoids but rather blocks their action at the receptor level [1]. *Flutamide* - **Flutamide** is an **androgen receptor antagonist** used primarily in the treatment of prostate cancer. - It works by blocking the binding of androgens to their receptors, thereby inhibiting androgen-mediated effects. *Finasteride* - **Finasteride** is a **5-alpha-reductase inhibitor**, preventing the conversion of testosterone to the more potent dihydrotestosterone (DHT) [3]. - It is used to treat benign prostatic hyperplasia (BPH) and male-pattern baldness, and does not affect glucocorticoid synthesis [3].

Q: What is the physiological dose of hydrocortisone (mg/m2/day)?

10-12 mg/m²/day. ***10-12 mg/m²/day*** - This range represents the typical **physiological replacement dose** of hydrocortisone, mimicking the body's natural cortisol production. - This dose is used for patients with **adrenal insufficiency** to maintain normal metabolic functions without causing significant side effects. *8-10 mg/m²/day* - This dose is slightly on the lower side of the accepted physiological range and might not be sufficient for complete replacement in all individuals. - While close, it is not the most commonly cited optimal physiological dose for hydrocortisone replacement. *15-18 mg/m²/day* - This dose is typically considered above the physiological replacement level and may begin to cause **mild corticosteroid side effects** with prolonged use. - It might be used for short periods or in specific conditions, but not as a standard physiological replacement. *20-25 mg/m²/day* - This dose is well above the physiological range and would be considered a **pharmacological dose** often used for its anti-inflammatory or immunosuppressive effects. - Prolonged use at this dose would likely lead to significant **corticosteroid side effects** such as Cushingoid features, osteoporosis, and hyperglycemia.

Q: What is the progestogen of choice in emergency contraception?

Levonorgestrel. ***Correct Option: Levonorgestrel*** - **Levonorgestrel** is the **progestogen of choice** for **emergency contraception** (Plan B, morning-after pill) - It works by **inhibiting or delaying ovulation**, preventing fertilization - Also alters **cervical mucus** to prevent sperm penetration and may affect endometrial receptivity - WHO-recommended as **single dose (1.5 mg)** or two doses (0.75 mg each, 12 hours apart) - Most effective when taken **within 72 hours** of unprotected intercourse, preferably within 24 hours *Incorrect Option: Norethisterone* - **Norethisterone** is a progestogen used in **oral contraceptive pills** and for managing gynecological conditions (menorrhagia, endometriosis, dysmenorrhea) - While it has progestational effects, it is **not the first-line choice** for emergency contraception - Less effective than levonorgestrel for post-coital contraception *Incorrect Option: Medroxyprogesterone* - **Medroxyprogesterone acetate** is used as a **long-acting depot contraceptive** (Depo-Provera injection every 3 months) - Also used for hormone replacement therapy and treating endometrial hyperplasia - **Not suitable for emergency contraception** due to its formulation and mechanism of action *Incorrect Option: Oxytocin* - **Oxytocin** is a posterior pituitary hormone that causes **uterine contractions** during labor and **milk ejection** during breastfeeding - It has **no role in contraception** or preventing pregnancy - Used therapeutically for labor induction, postpartum hemorrhage prevention, and augmentation of labor

Q: Which of the following statements about glucocorticoids is true?

Glucocorticoids downregulate MHC class II expression.. ***Glucocorticoids downregulate MHC class II expression.*** - Glucocorticoids exert **immunosuppressive effects** by reducing the expression of **MHC class II molecules** on antigen-presenting cells. - This downregulation impairs the ability of antigen-presenting cells to activate **CD4+ T-helper cells**, thereby suppressing adaptive immune responses. *Glucocorticoids directly activate T-helper cells.* - Glucocorticoids do not directly activate T-helper cells; rather, they have an **inhibitory effect** on T-cell function and proliferation. - They tend to promote **T-cell apoptosis** and reduce cytokine production, thus dampening T-helper cell responses. *Glucocorticoids have no effect on immune cells.* - This statement is incorrect as glucocorticoids have profound and widespread **immunosuppressive and anti-inflammatory effects** on various immune cells. - They influence the function, proliferation, and survival of **lymphocytes, macrophages, and granulocytes**. *Glucocorticoids enhance the activity of cytotoxic T cells.* - Glucocorticoids generally **suppress immune responses**, including the activity of **cytotoxic T cells (CTLs)**, rather than enhancing it. - They tend to inhibit the production of **interleukins** necessary for CTL activation and proliferation.

Q: Which antithyroid drug is preferred during the first trimester of pregnancy due to relatively lower placental transfer?

Propylthiouracil. ***Propylthiouracil*** - **Propylthiouracil (PTU)** is the preferred antithyroid drug during the **first trimester** of pregnancy because it crosses the placenta less readily than methimazole/carbimazole. - While it still crosses the placenta, its lower placental transfer and association with fewer fetal anomalies in early pregnancy make it a safer initial choice, especially to minimize the risk of **fetal embryopathy** associated with methimazole. *Carbimazole* - **Carbimazole** (which is metabolized to methimazole) can cross the placenta more easily than PTU and has been associated with **fetal anomalies**, particularly in the first trimester. - Its use is generally avoided during the first trimester due to concerns about congenital malformations such as **aplasia cutis** and **esophageal atresia**. *Both* - While both drugs can cross the placenta to some extent, their safety profiles and recommended use during pregnancy differ significantly. - Carbimazole (methimazole) has a higher risk of teratogenicity in the first trimester compared to PTU. *None of the options* - This option is incorrect because propylthiouracil is indeed known to cross the placenta and is commonly used in pregnancy, especially during the first trimester. - The choice of antithyroid drug is a critical consideration in managing hyperthyroidism in pregnancy.

Q: Which of the following oral antidiabetic drugs is an insulin secretagogue?

Nateglinide. **Nateglinide** - **Nateglinide** is a **meglitinide**, which is a type of **insulin secretagogue**. - It stimulates **insulin release** from pancreatic beta cells by blocking ATP-sensitive potassium channels. *Metformin* - **Metformin** is a **biguanide** that primarily works by **decreasing hepatic glucose production** and increasing insulin sensitivity in peripheral tissues. - It does not directly stimulate insulin secretion. *Pioglitazone* - **Pioglitazone** is a **thiazolidinedione** (TZD) that improves insulin sensitivity by activating **PPAR-gamma receptors**. - It does not directly affect insulin secretion but rather enhances the body's response to existing insulin. *Acarbose* - **Acarbose** is an **alpha-glucosidase inhibitor** that delays the digestion and absorption of carbohydrates in the small intestine. - This reduces postprandial glucose excursions and does not directly stimulate insulin secretion.

Q: Which of the following antidiabetic drugs is a GLP-1 receptor agonist?

Exenatide. ***Exenatide*** - **Exenatide** is a synthetic analog of **glucagon-like peptide-1 (GLP-1)**, acting as a GLP-1 receptor agonist [1]. - It works by stimulating **insulin secretion** in a glucose-dependent manner, suppressing glucagon release, slowing gastric emptying, and promoting satiety [2], [3]. - Other GLP-1 agonists include liraglutide, dulaglutide, and semaglutide [1]. *Pramlintide* - **Pramlintide** is an **amylin analog**, not a GLP-1 receptor agonist. - It is used in both type 1 and type 2 diabetes to slow gastric emptying, suppress glucagon secretion, and promote satiety, but it acts via **amylin receptors**. *Glucomannan* - **Glucomannan** is a **dietary fiber** derived from the konjac plant, used as a food additive and supplement for weight loss and constipation. - It does not directly affect GLP-1 receptors or regulate insulin or glucagon secretion as a pharmacological agent. *Sitagliptin* - **Sitagliptin** is a **DPP-4 inhibitor** (dipeptidyl peptidase-4 inhibitor), not a GLP-1 receptor agonist [2]. - While it enhances endogenous GLP-1 activity by preventing its degradation, it does not directly stimulate GLP-1 receptors like exenatide does [4].

Q: The mechanism by which ergometrine stops postpartum hemorrhage is that it:

Increases tone of uterine muscle. ***Increases tone of uterine muscle*** - **Ergometrine** is an **ergot alkaloid** that directly stimulates **uterine smooth muscle contractions**. - These sustained contractions lead to **compression of blood vessels within the myometrium**, thereby reducing blood flow and controlling **postpartum hemorrhage**. *Causes vasoconstriction of uterine arteries* - While ergometrine does have some generalized **vasoconstrictive effects**, its primary mechanism of action in controlling postpartum hemorrhage is not mainly through direct vasoconstriction of large uterine arteries. - The crucial effect is the **sustained uterine contraction** which mechanically occludes blood vessels, rather than chemical constriction of the vessels themselves. *Induces platelet aggregation* - Ergometrine does not primarily act by inducing **platelet aggregation**; this is a function of specific clotting factors and platelet activators. - Its therapeutic effect against hemorrhage is mediated through its action on **uterine contractility**, not on the cellular components of coagulation. *Promotes coagulation* - Ergometrine does not directly promote the **coagulation cascade** or enhance the formation of fibrin clots. - Its mechanism of action is distinct from agents that affect intrinsic or extrinsic pathways of coagulation.

Question 1

Which drug is primarily used to promote fetal lung maturity?

Accepted Answer

Dexamethasone

Answer

Folic acid

Answer

Beclomethasone

Question 2

Which of the following is glucocorticoid synthesis inhibitor?

Accepted Answer

Metyrapone

Answer

Mifepristone

Answer

Flutamide

Answer

Finasteride

Question 3

What is the physiological dose of hydrocortisone (mg/m2/day)?

Accepted Answer

10-12 mg/m²/day

Answer

20-25 mg/m²/day

Answer

15-18 mg/m²/day

Answer

8-10 mg/m²/day

Question 4

What is the progestogen of choice in emergency contraception?

Accepted Answer

Levonorgestrel

Answer

Norethisterone

Answer

Medroxyprogesterone

Answer

Oxytocin

Question 5

A 47-year-old woman presents with complaints of nervousness and increased sensitivity to hot weather. She is diagnosed with hyperthyroidism and prescribed propylthiouracil. What is the principal mechanism by which this drug acts?

Accepted Answer

Inhibiting the enzyme thyroid peroxidase, which reduces the synthesis of thyroid hormones.

Answer

Reducing the proteolysis of thyroglobulin.

Answer

Inhibiting the binding of TSH to its receptor.

Answer

Altering the levels of reverse T3 (rT3) in the body.

Question 6

Which of the following statements about glucocorticoids is true?

Accepted Answer

Glucocorticoids downregulate MHC class II expression.

Answer

Glucocorticoids directly activate T-helper cells.

Answer

Glucocorticoids have no effect on immune cells.

Answer

Glucocorticoids enhance the activity of cytotoxic T cells.

Question 7

Which antithyroid drug is preferred during the first trimester of pregnancy due to relatively lower placental transfer?

Accepted Answer

Propylthiouracil

Answer

Carbimazole

Answer

Both

Answer

None of the options

Question 8

Which of the following oral antidiabetic drugs is an insulin secretagogue?

Accepted Answer

Nateglinide

Answer

Metformin

Answer

Pioglitazone

Answer

Acarbose

Question 9

Which of the following antidiabetic drugs is a GLP-1 receptor agonist?

Accepted Answer

Exenatide

Answer

Pramlintide

Answer

Glucomannan

Answer

Sitagliptin

Question 10

The mechanism by which ergometrine stops postpartum hemorrhage is that it:

Accepted Answer

Increases tone of uterine muscle

Answer

Induces platelet aggregation

Answer

Promotes coagulation

Answer

Causes vasoconstriction of uterine arteries

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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