Endocrine Pharmacology Practice Questions

Q: Which of the following is NOT an anti-androgenic drug?

Cypionate. **Explanation:** The correct answer is **Cypionate**. To answer this question correctly, one must distinguish between anti-androgens (which inhibit androgen action or synthesis) and androgen esters (which act as pro-drugs for testosterone). **Why Cypionate is the correct answer:** **Testosterone Cypionate** is a long-acting ester of testosterone. It is an **androgen agonist**, not an antagonist. It is administered intramuscularly to treat male hypogonadism and delayed puberty. The suffix "-ate" (like cypionate, enanthate, or propionate) typically denotes an esterified form of the hormone used for replacement therapy. **Why the other options are incorrect:** * **Flutamide:** A potent **competitive antagonist** at the androgen receptor. It is primarily used in the management of prostatic carcinoma. * **Spironolactone:** Primarily an aldosterone antagonist (potassium-sparing diuretic), but it also possesses significant **anti-androgenic activity** by displacing testosterone from its receptor and inhibiting androgen synthesis. It is used clinically for hirsutism in females. * **Finasteride:** A **5-alpha reductase inhibitor** that prevents the conversion of testosterone to the more potent dihydrotestosterone (DHT). It is used for Benign Prostatic Hyperplasia (BPH) and male pattern baldness. **High-Yield NEET-PG Pearls:** 1. **Bicalutamide** is preferred over Flutamide for prostate cancer due to less hepatotoxicity and once-daily dosing. 2. **Cyproterone acetate** is another anti-androgen used for severe acne and precocious puberty. 3. **Abiraterone** inhibits CYP17, blocking the synthesis of androgens in both the testes and adrenal glands; it is used in castration-resistant prostate cancer. 4. **Finasteride vs. Dutasteride:** Finasteride inhibits Type II 5-alpha reductase, while Dutasteride inhibits both Type I and Type II.

Q: Which 5α reductase inhibitor is effective for both benign prostatic hypertrophy and male pattern baldness?

Finasteride. **Explanation:** **Finasteride** is the correct answer because it is a selective inhibitor of the **Type II 5α-reductase enzyme**. This enzyme is responsible for converting testosterone into the more potent androgen, **Dihydrotestosterone (DHT)**. * **In BPH:** DHT is the primary mediator of prostatic growth. By lowering intraprostatic DHT levels, Finasteride reduces prostate volume, improves urinary flow, and prevents disease progression. * **In Male Pattern Baldness (Androgenetic Alopecia):** DHT causes miniaturization of hair follicles. Finasteride (at a lower dose of 1mg) prevents this process, promoting hair regrowth and preventing further loss. **Analysis of Incorrect Options:** * **Flutamide:** This is a competitive **Androgen Receptor Antagonist** (not an enzyme inhibitor). It is primarily used in the treatment of metastatic prostate cancer, not BPH or baldness. * **Prazosin:** This is a non-selective **α1-blocker**. While it is used for BPH, it works by relaxing the smooth muscle of the bladder neck (dynamic component) and has no effect on hormone levels or hair growth. * **Minoxidil:** While used for baldness, it is a **K+ channel opener** (vasodilator). It works by increasing blood flow to follicles, not by inhibiting 5α-reductase. **High-Yield Clinical Pearls for NEET-PG:** * **Dutasteride:** A non-selective inhibitor of **both Type I and Type II** 5α-reductase; it is more potent and has a longer half-life than Finasteride. * **Teratogenicity:** 5α-reductase inhibitors are Category X; pregnant women should not even handle crushed tablets due to the risk of feminization of a male fetus. * **PSA Levels:** Finasteride can decrease PSA levels by approximately 50%; this must be accounted for when screening for prostate cancer.

Q: Which of the following hormones is orally active?

Thyroxine. Explanation: The oral bioavailability of a hormone is primarily determined by its chemical structure. Hormones that are **proteins or peptides** are susceptible to degradation by gastric acid and proteolytic enzymes (like pepsin and trypsin) in the gastrointestinal tract, rendering them inactive if swallowed. Why Thyroxine (T4) is correct: Thyroxine is an amino acid derivative (iodinated tyrosine). Unlike large proteins, it is a small, relatively stable molecule that is well-absorbed from the small intestine (primarily the jejunum and ileum). This stability allows it to be administered orally, which is the standard route for long-term replacement therapy in hypothyroidism. Why the other options are incorrect: * **TSH (Thyroid Stimulating Hormone):** This is a large glycoprotein. If taken orally, it would be digested into its constituent amino acids and lose all biological activity. * **GH (Growth Hormone):** This is a 191-amino acid polypeptide. It must be administered parenterally (subcutaneously) because it is rapidly proteolyzed in the stomach. * **Prolactin:** Similar to GH, prolactin is a protein hormone. It lacks oral activity due to enzymatic degradation in the gut. High-Yield Clinical Pearls for NEET-PG: * **Absorption Fact:** Oral absorption of Thyroxine is decreased by food, calcium carbonate, ferrous sulfate, and proton pump inhibitors (PPIs). It should be taken on an empty stomach [1]. * **Steroid Hormones:** Like Thyroxine, steroid hormones (e.g., Estrogen, Testosterone derivatives) are also orally active because they are lipophilic and resistant to gastric digestion. * **Exceptions:** Insulin and Oxytocin are classic examples of peptide hormones that **cannot** be given orally.

Q: Which of the following medications can be safely used in pregnancy?

Propylthiouracil. **Explanation:** **Propylthiouracil (PTU)** is the drug of choice for managing hyperthyroidism during the **first trimester** of pregnancy. While both PTU and Methimazole cross the placenta, PTU is more extensively protein-bound, leading to less placental transfer. More importantly, Methimazole is avoided in early pregnancy due to its association with **choanal atresia** and **aplasia cutis** (Methimazole embryopathy). PTU is preferred initially, though many clinicians switch to Methimazole in the second and third trimesters to avoid PTU-induced maternal hepatotoxicity. **Incorrect Options:** * **ACE Inhibitors (e.g., Enalapril) & AT Receptor Antagonists (ARBs, e.g., Losartan):** Both are strictly contraindicated (Category X/D) throughout pregnancy, especially in the 2nd and 3rd trimesters. They interfere with fetal renal development, leading to **oligohydramnios**, fetal renal failure, hypocalvaria (skull defects), and pulmonary hypoplasia. * **Aldosterone:** While not a standard medication, mineralocorticoid antagonists (like Spironolactone) are generally avoided due to potential anti-androgenic effects on the developing male fetus. **NEET-PG High-Yield Pearls:** * **Safe Antihypertensives in Pregnancy:** Remember the mnemonic **"Better Mother Care During Hypertensive"** (B-Blockers/Labetalol, Methyldopa, Calcium Channel Blockers/Nifedipine, Hydralazine). * **Methyldopa** is the traditional drug of choice for chronic hypertension in pregnancy. * **Labetalol** is currently preferred for acute management of hypertensive emergencies in pregnancy. * **Teratogenic effect of Methimazole:** Aplasia cutis (congenital focal absence of skin).

Q: Which of the following is a long-acting glucocorticoid?

Dexamethasone. **Explanation:** Glucocorticoids are classified based on their duration of action (biological half-life), which correlates with their anti-inflammatory potency and mineralocorticoid (salt-retaining) activity. **1. Why Dexamethasone is Correct:** **Dexamethasone** is a **long-acting** glucocorticoid with a biological half-life of **36–54 hours**. It is highly potent (about 25–30 times more potent than hydrocortisone) and possesses negligible mineralocorticoid activity. This makes it ideal for conditions requiring sustained suppression of inflammation or the immune system, such as cerebral edema or as a diagnostic tool in the Dexamethasone Suppression Test (DST). **2. Why the Other Options are Incorrect:** * **Hydrocortisone (Option D):** This is a **short-acting** glucocorticoid (half-life 8–12 hours). It is the pharmaceutical form of cortisol and has significant mineralocorticoid activity, making it the drug of choice for replacement therapy in adrenal insufficiency. * **Prednisolone (Option C):** This is an **intermediate-acting** glucocorticoid (half-life 18–36 hours). It is commonly used for chronic inflammatory and autoimmune conditions. * **Triamcinolone (Option B):** Also an **intermediate-acting** steroid. It is notable for having zero mineralocorticoid activity and is frequently used in topical or intra-articular preparations. **NEET-PG High-Yield Pearls:** * **Potency Rule:** As the duration of action increases, anti-inflammatory potency increases, while mineralocorticoid activity decreases. * **Betamethasone:** Another long-acting steroid; it is specifically used to accelerate **fetal lung maturity** in preterm labor because it crosses the placental barrier and has low protein binding. * **Mnemonic for Duration:** * **Short:** Hydrocortisone, Cortisone. * **Intermediate:** Prednisolone, Triamcinolone, Methylprednisolone. * **Long:** Dexamethasone, Betamethasone.

Q: Which of the following drugs is used to treat both diabetes mellitus and diabetes insipidus?

Chlorpropamide. **Explanation:** **Chlorpropamide** is a first-generation sulfonylurea that is unique because it possesses clinical utility in both Diabetes Mellitus (DM) and Central Diabetes Insipidus (DI). 1. **Mechanism in Diabetes Mellitus:** Like other sulfonylureas, it stimulates insulin release from pancreatic beta cells by blocking ATP-sensitive potassium channels ($K_{ATP}$), leading to depolarization and calcium influx. 2. **Mechanism in Diabetes Insipidus:** Chlorpropamide treats Central DI through two mechanisms: * It sensitizes the renal collecting ducts to the action of endogenous Antidiuretic Hormone (ADH/Vasopressin). * It may stimulate a modest increase in the release of ADH from the posterior pituitary. * *Note:* It is ineffective in Nephrogenic DI because the renal receptors are non-functional. **Why other options are incorrect:** * **Glibenclamide, Gliclazide, and Glipizide:** These are second-generation sulfonylureas. While they are significantly more potent than chlorpropamide for treating Type 2 DM, they lack the ADH-sensitizing effect required to treat Diabetes Insipidus. **High-Yield Clinical Pearls for NEET-PG:** * **Disulfiram-like reaction:** Chlorpropamide is notorious for causing a disulfiram-like reaction when consumed with alcohol. * **Dilutional Hyponatremia:** Due to its ADH-potentiating effect (SIADH-like picture), chlorpropamide can cause significant hyponatremia, especially in elderly patients. * **Longest Half-life:** It has the longest duration of action among sulfonylureas, increasing the risk of prolonged hypoglycemia. * **Other drugs for DI:** Thiazides (Paradoxical effect in Nephrogenic DI), Amiloride (Lithium-induced DI), and Desmopressin (Drug of choice for Central DI).

Q: Which oral hypoglycemic drug is least likely to cause hypoglycemia?

Rosiglitazone. ### Explanation The risk of hypoglycemia with oral hypoglycemic agents (OHAs) depends primarily on whether the drug’s mechanism is **insulin-independent** or **insulin-secretagogue** based. **1. Why Rosiglitazone is the Correct Answer:** Rosiglitazone belongs to the **Thiazolidinedione (TZD)** class. These drugs act as agonists for the **PPAR-γ receptor**, which increases peripheral insulin sensitivity (primarily in adipose tissue, muscle, and liver). Because TZDs do not stimulate the pancreas to release more insulin but rather make existing insulin work more efficiently, they are considered **"euglycemic"** agents. They do not cause hypoglycemia when used as monotherapy. **2. Why the Other Options are Incorrect:** * **Gliclazide & Glimepiride (Options B & D):** These are **Sulfonylureas**. They act by closing ATP-sensitive K⁺ channels in pancreatic beta cells, leading to depolarization and forced insulin secretion regardless of blood glucose levels. Hypoglycemia is their most common and significant side effect. * **Repaglinide (Option A):** This is a **Meglitinide** (Glinide). Like sulfonylureas, it is an insulin secretagogue. Although it has a shorter duration of action and is taken pre-prandially, it still carries a distinct risk of hypoglycemia if a meal is delayed or skipped. **3. NEET-PG High-Yield Pearls:** * **Weight Gain:** Both TZDs and Sulfonylureas cause weight gain, but via different mechanisms (TZDs cause fluid retention and fat redistribution; Sulfonylureas are anabolic due to high insulin). * **TZD Side Effects:** Watch for **fluid retention/edema** (contraindicated in CHF), **bone fractures** (osteoporosis risk), and bladder cancer (specifically associated with Pioglitazone). * **Drug of Choice:** Metformin (a Biguanide) is also an insulin sensitizer and, like TZDs, has a very low risk of hypoglycemia, making it the first-line treatment for Type 2 Diabetes.

Question 1

Which of the following is NOT an anti-androgenic drug?

Accepted Answer

Cypionate

Answer

Flutamide

Answer

Spironolactone

Answer

Finasteride

Question 2

Which 5α reductase inhibitor is effective for both benign prostatic hypertrophy and male pattern baldness?

Accepted Answer

Finasteride

Answer

Flutamide

Answer

Prazosin

Answer

Minoxidil

Question 3

Which of the following hormones is orally active?

Accepted Answer

Thyroxine

Answer

TSH

Answer

GH

Answer

Prolactin

Question 4

Calcitonin is used in all of the following conditions, EXCEPT:

Accepted Answer

Fanconi syndrome

Answer

Hypervitaminosis D

Answer

Postmenopausal osteoporosis

Answer

Paget's disease

Question 5

Which of the following medications can be safely used in pregnancy?

Accepted Answer

Propylthiouracil

Answer

ACE inhibitors

Answer

Aldosterone

Answer

AT receptor antagonist

Question 6

Which of the following is a long-acting glucocorticoid?

Accepted Answer

Dexamethasone

Answer

Triamcinolone

Answer

Prednisolone

Answer

Hydrocortisone

Question 7

All of the following increase insulin release except?

Accepted Answer

Rosiglitazone

Answer

Nateglinide

Answer

Glipizide

Answer

Exenatide

Question 8

A 55-year-old diabetic man presents to the emergency room in an unresponsive state. His laboratory values show PCO2 19 mm Hg, HCO3 11 mEq/L, and pH 6.9. What is the most appropriate immediate treatment for this patient?

Accepted Answer

Administration of insulin

Answer

Administration of an oral hypoglycemic agent

Answer

Administration of bicarbonate

Answer

Close observation only

Question 9

Which of the following drugs is used to treat both diabetes mellitus and diabetes insipidus?

Accepted Answer

Chlorpropamide

Answer

Glibenclamide

Answer

Glicazide

Answer

Glipizide

Question 10

Which oral hypoglycemic drug is least likely to cause hypoglycemia?

Accepted Answer

Rosiglitazone

Answer

Repaglinide

Answer

Gliclazide

Answer

Glimipiride

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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