Endocrine Pharmacology Practice Questions

Q: Which of the following drugs is used in the management of diabetes mellitus?

Bromocriptine. **Explanation:** **Bromocriptine (Option A)** is a dopamine D2 receptor agonist traditionally used for Parkinson’s disease and hyperprolactinemia [1]. However, a specific **quick-release (QR) formulation** of Bromocriptine is FDA-approved for the management of Type 2 Diabetes Mellitus. * **Mechanism:** It acts on the circadian rhythm in the hypothalamus to reset abnormally low dopaminergic tone in the morning. This leads to a reduction in hepatic glucose production, decreased insulin resistance, and lower free fatty acid levels without increasing insulin secretion. **Analysis of Incorrect Options:** * **B. Octreotide:** A somatostatin analogue used for acromegaly and secretory diarrheas. It actually **inhibits insulin release** and can potentially worsen glycemic control or cause hypoglycemia/hyperglycemia. * **C. Prednisolone:** A glucocorticoid that is notoriously **diabetogenic**. It increases gluconeogenesis and causes peripheral insulin resistance, often leading to steroid-induced diabetes. * **D. Pegvisomant:** A growth hormone receptor antagonist used specifically for **acromegaly** that does not respond to other treatments. **High-Yield Clinical Pearls for NEET-PG:** * **Bromocriptine QR** is the only dopaminergic drug approved for T2DM [2]. It is weight-neutral and has a low risk of hypoglycemia. * Other "non-traditional" drugs for T2DM include **Colesevelam** (a bile acid sequestrant) [3]. * **Side Effects of Bromocriptine:** Nausea, dizziness, and orthostatic hypotension are common during initiation. * **Contraindication:** It should not be used in patients with syncopal migraines or those nursing (as it inhibits prolactin).

Q: All of the following are true about estrogen, EXCEPT:

Used in the treatment of gynecomastia. **Explanation:** The correct answer is **B. Used in the treatment of gynecomastia.** **Why Option B is the Exception:** Gynecomastia is the enlargement of glandular breast tissue in males, typically caused by an imbalance between estrogen and androgen actions (increased estrogen or decreased testosterone). Administering estrogen would **worsen** or even cause gynecomastia, not treat it. In fact, estrogen therapy (used in prostate cancer) is a well-known cause of this condition. Treatment usually involves Selective Estrogen Receptor Modulators (SERMs) like **Tamoxifen**, which block estrogen receptors in breast tissue. **Analysis of Other Options:** * **A. Causes cholestasis:** Estrogens decrease the activity of the bile salt export pump (BSEP) and increase cholesterol secretion into bile, leading to cholestasis and an increased risk of gallstones. * **C. Used in HRT (Hormone Replacement Therapy):** Estrogen is a cornerstone of HRT for managing postmenopausal symptoms (vasomotor instability, vaginal atrophy) and preventing osteoporosis. * **D. Increased risk of breast cancer:** Prolonged exposure to estrogen (especially when unopposed by progesterone) is a documented risk factor for breast and endometrial cancers due to its proliferative effects on these tissues. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolic Effects:** Estrogens increase HDL and decrease LDL (cardioprotective) but increase triglycerides. * **Coagulation:** They increase the synthesis of clotting factors (II, VII, IX, X) and decrease Antithrombin III, increasing the risk of **Thromboembolism**. * **Contraindications:** Estrogen should be avoided in patients with a history of undiagnosed vaginal bleeding, estrogen-dependent tumors, or active thromboembolic disease.

Q: Which one of the following drugs is NOT a uterine relaxant?

Dopamine. **Explanation:** Uterine relaxants, also known as **Tocolytics**, are drugs used to delay preterm labor by inhibiting uterine contractions. The physiological basis for uterine relaxation primarily involves the stimulation of **$\beta_2$-adrenergic receptors** located on the myometrium. **Why Dopamine is the correct answer:** Dopamine is a catecholamine that acts predominantly on dopaminergic ($D_1, D_2$) and adrenergic ($\alpha_1, \beta_1$) receptors. It does **not** have a significant effect on $\beta_2$-receptors in the uterus. Its primary clinical uses are in the management of cardiogenic shock and hemodynamic instability, where it increases cardiac output and maintains renal perfusion. It has no role as a tocolytic. **Analysis of Incorrect Options:** * **Isoxsuprine:** A traditional $\beta$-receptor agonist formerly widely used as a uterine relaxant and peripheral vasodilator. * **Salbutamol & Terbutaline:** These are selective **$\beta_2$-agonists**. While commonly known as bronchodilators, they also relax the myometrium by increasing intracellular cAMP, which leads to a decrease in calcium levels and inhibition of myosin light chain kinase. Terbutaline is frequently used off-label to arrest preterm labor. **NEET-PG High-Yield Pearls:** * **Drug of Choice (DOC):** Currently, **Atosiban** (Oxytocin antagonist) or **Nifedipine** (Calcium Channel Blocker) are preferred over $\beta_2$-agonists due to a better side-effect profile. * **Specific Side Effects:** $\beta_2$-agonists used as tocolytics can cause maternal tachycardia, palpitations, and **pulmonary edema**. * **Other Tocolytics:** Magnesium sulfate (acts by competing with Calcium) and Indomethacin (NSAID; inhibits prostaglandin synthesis).

Q: All the listed drugs have anti-androgenic effects EXCEPT:

Progesterone. **Explanation:** The correct answer is **Progesterone**. While progesterone is a precursor to androgens in the biosynthetic pathway, it does not possess clinically significant anti-androgenic properties. In fact, some synthetic progestins (like medroxyprogesterone) can exhibit weak androgenic activity. **Why the other options are incorrect:** * **Dutasteride:** This is a **5-alpha reductase inhibitor**. It prevents the conversion of testosterone to the more potent dihydrotestosterone (DHT), thereby exerting an anti-androgenic effect. It is commonly used in Benign Prostatic Hyperplasia (BPH). * **Flutamide:** This is a **pure androgen receptor antagonist**. It competitively inhibits the binding of endogenous androgens to their receptors. It is primarily used in the management of metastatic prostatic carcinoma. * **Spironolactone:** Primarily an aldosterone antagonist (potassium-sparing diuretic), it also acts as a **weak androgen receptor antagonist** and inhibits steroidogenesis. It is frequently used off-label to treat hirsutism and acne in women. **High-Yield Clinical Pearls for NEET-PG:** * **Finasteride vs. Dutasteride:** Finasteride inhibits Type II 5-alpha reductase; Dutasteride inhibits both Type I and Type II isoenzymes. * **Cyproterone Acetate:** A progestin with significant anti-androgenic activity used in precocious puberty and severe hirsutism. * **Ketoconazole:** An antifungal that, at high doses, inhibits CYP17 (17,20-lyase), effectively inhibiting androgen synthesis; used in refractory prostate cancer or Cushing's syndrome. * **Bicalutamide:** Preferred over Flutamide in prostate cancer due to less hepatotoxicity and once-daily dosing.

Q: Dopamine acts on D2 receptors, which have an inhibitory effect on prolactin secretion. If D2 receptors are blocked, which of the following effects will not be seen?

Visual disturbance. **Explanation:** The question tests the understanding of the **Tuberoinfundibular pathway** and the clinical manifestations of hyperprolactinemia. **1. Why "Visual Disturbance" is the correct answer:** Dopamine acts as the primary Prolactin Inhibiting Hormone (PIH). Blocking D2 receptors (e.g., by antipsychotics like Haloperidol or Metoclopramide) leads to **Hyperprolactinemia**. Visual disturbances (specifically bitemporal hemianopia) occur due to **mechanical compression** of the optic chiasm by a large pituitary tumor (Macroadenoma). Simply blocking D2 receptors increases prolactin levels biochemically but does not cause a physical mass effect or tumor growth; therefore, visual field defects will not be seen. **2. Analysis of Incorrect Options:** * **Gonadal dysfunction:** High prolactin inhibits the release of GnRH from the hypothalamus. This leads to decreased LH and FSH, resulting in infertility, amenorrhea in females, and decreased libido or impotence in males. * **Headache:** While more common with tumors, acute biochemical hyperprolactinemia and the underlying cause of D2 blockade can be associated with non-specific headaches. * **Excessive lactation (Galactorrhea):** This is a direct result of prolactin’s action on mammary glands, stimulating milk production in the absence of pregnancy. **Clinical Pearls for NEET-PG:** * **Drug-Induced Hyperprolactinemia:** The most common cause of elevated prolactin (after pregnancy). Key drugs include Antipsychotics, Reserpine, Metoclopramide, and Methyldopa. * **Dopamine Agonists:** Bromocriptine and **Cabergoline** (preferred due to higher D2 selectivity and longer half-life) are used to treat prolactinomas. * **Hook Effect:** A laboratory phenomenon where extremely high prolactin levels give a falsely low reading; requires sample dilution for accurate diagnosis.

Q: Which drug is used in intracavernous injection for erectile dysfunction?

Alprostadil. **Explanation:** **Alprostadil** is a synthetic analogue of **Prostaglandin E1 (PGE1)**. Its mechanism of action involves increasing intracellular cAMP, which leads to the relaxation of smooth muscles in the corpus cavernosum and vasodilation of cavernosal arteries. This increases blood flow to the penis, inducing an erection. While PDE-5 inhibitors are first-line oral treatments, intracavernous alprostadil is a highly effective second-line therapy for patients who do not respond to or cannot tolerate oral medications. **Analysis of Incorrect Options:** * **Epoprostrenol (Option A):** This is a synthetic **Prostaglandin I2 (PGI2/Prostacyclin)** analogue. It is primarily used via intravenous infusion for the treatment of **Pulmonary Arterial Hypertension (PAH)**, not erectile dysfunction. * **Sildenafil & Tadalafil (Options C & D):** These are **Phosphodiesterase-5 (PDE-5) inhibitors**. While they are the gold standard for erectile dysfunction, they are administered **orally**. They require sexual stimulation to work (by preventing the breakdown of cGMP) and are not used as intracavernous injections. **High-Yield Clinical Pearls for NEET-PG:** * **Triple Therapy (Murex):** For resistant cases, a combination of **Papaverine** (non-selective PDE inhibitor), **Phentolamine** (alpha-blocker), and **Alprostadil** is used intracavernously. * **Side Effects:** The most common side effect of intracavernous alprostadil is penile pain. The most serious complication is **priapism** (prolonged erection >4 hours), which is a medical emergency. * **MUSE:** Alprostadil can also be administered as a Medicated Urethral System for Erection (intraurethral suppository).

Q: Compared to hydrocortisone, which of the following has the maximum glucocorticoid activity?

Dexamethasone. ### Explanation The potency of corticosteroids is determined by their relative **glucocorticoid** (anti-inflammatory) and **mineralocorticoid** (salt-retaining) activities. Hydrocortisone (cortisol) is used as the standard reference with a potency ratio of 1:1. **Why Dexamethasone is Correct:** Dexamethasone is a long-acting synthetic glucocorticoid. It has the highest anti-inflammatory potency among the options provided, being approximately **25 to 30 times more potent than hydrocortisone**. Crucially, it possesses **zero mineralocorticoid activity**, making it ideal for conditions where fluid retention must be avoided (e.g., cerebral edema). **Analysis of Incorrect Options:** * **Cortisone:** This is a prodrug that must be converted to cortisol in the liver. It is actually *less* potent than hydrocortisone (0.8x potency). * **Prednisolone:** An intermediate-acting steroid with approximately **4 times** the anti-inflammatory potency of hydrocortisone. It retains some mineralocorticoid activity. * **Methylprednisolone:** Also an intermediate-acting steroid, it is slightly more potent than prednisolone, with approximately **5 times** the potency of hydrocortisone. **High-Yield NEET-PG Pearls:** 1. **Potency Hierarchy:** Dexamethasone = Betamethasone (25–30x) > Methylprednisolone (5x) > Prednisolone (4x) > Hydrocortisone (1x) > Cortisone (0.8x). 2. **Duration of Action:** Dexamethasone is **long-acting** (t½: 36–72 hours), whereas Prednisolone is intermediate-acting (t½: 12–36 hours). 3. **DOC for Fetal Lung Maturity:** Betamethasone or Dexamethasone are preferred because they poorly bind to transcortin and cross the placenta in active forms. 4. **Mineralocorticoid Powerhouse:** Fludrocortisone has the highest mineralocorticoid activity and is used in Addison’s disease.

Q: Biguanides act by which of the following mechanisms, except?

Stimulating insulin release from the pancreas. **Explanation:** **Biguanides (e.g., Metformin)** are classified as **euglycemic agents** or insulin sensitizers. Unlike Sulfonylureas and Meglitinides, they do not stimulate the pancreas to produce more insulin. **1. Why Option A is the Correct Answer (The "Except"):** Metformin does not act on the pancreatic beta cells to stimulate insulin secretion. Therefore, it does not cause hyperinsulinemia or hypoglycemia when used as monotherapy. This is the fundamental distinction between biguanides and "insulin secretagogues." **2. Analysis of Other Options:** * **Inhibiting Gluconeogenesis (Option C):** This is the **primary mechanism** of Metformin. It activates AMP-activated protein kinase (AMPK), which suppresses hepatic glucose production (gluconeogenesis) and glycogenolysis. * **Enhancing Insulin Binding (Option D):** Metformin increases the sensitivity of peripheral tissues (muscle and fat) to insulin by improving receptor binding and increasing the translocation of glucose transporters (GLUT-4) to the cell membrane. * **Promoting Glycolysis (Option B):** By activating AMPK, Metformin enhances anaerobic glycolysis in the tissues, which increases the peripheral utilization of glucose. **Clinical Pearls for NEET-PG:** * **Drug of Choice:** Metformin is the first-line drug for Type 2 Diabetes Mellitus, especially in obese patients, as it promotes modest weight loss. * **Adverse Effects:** The most common side effects are GI-related (diarrhea, metallic taste). The most serious, though rare, is **Lactic Acidosis** (due to inhibition of gluconeogenesis from lactate). * **Vitamin Deficiency:** Long-term use can lead to **Vitamin B12 deficiency** due to malabsorption. * **Contraindication:** It is contraindicated in patients with significant renal impairment (eGFR <30 mL/min) due to the risk of lactic acidosis.

Question 1

Which of the following drugs is used in the management of diabetes mellitus?

Accepted Answer

Bromocriptine

Answer

Octreotide

Answer

Prednisolone

Answer

Pegvisomant

Question 2

Among the following, which 5-PDE inhibitor has the longest duration of action?

Accepted Answer

Tadalafil

Answer

Sildenafil

Answer

Vardenafil

Answer

Udenafil

Question 3

All of the following are advantages of using raloxifene over estrogen in post-menopausal women EXCEPT?

Accepted Answer

Reduces incidence of venous thrombosis

Answer

Reduces fracture rates

Answer

Avoids endometrial hyperplasia

Answer

No increase in incidence of breast carcinoma

Question 4

All of the following are true about estrogen, EXCEPT:

Accepted Answer

Used in the treatment of gynecomastia

Answer

Causes cholestasis

Answer

Used in H

Answer

Increased risk of breast cancer

Question 5

Which one of the following drugs is NOT a uterine relaxant?

Accepted Answer

Dopamine

Answer

Isoxsuprine

Answer

Salbutamol

Answer

Terbutaline

Question 6

All the listed drugs have anti-androgenic effects EXCEPT:

Accepted Answer

Progesterone

Answer

Dutasteride

Answer

Flutamide

Answer

Spironolactone

Question 7

Dopamine acts on D2 receptors, which have an inhibitory effect on prolactin secretion. If D2 receptors are blocked, which of the following effects will not be seen?

Accepted Answer

Visual disturbance

Answer

Gonadal dysfunction

Answer

Headache

Answer

Excessive lactation

Question 8

Which drug is used in intracavernous injection for erectile dysfunction?

Accepted Answer

Alprostadil

Answer

Epoprostrenol

Answer

Sildenafil

Answer

Tadalafil

Question 9

Compared to hydrocortisone, which of the following has the maximum glucocorticoid activity?

Accepted Answer

Dexamethasone

Answer

Cortisone

Answer

Prednisolone

Answer

Methylprednisolone

Question 10

Biguanides act by which of the following mechanisms, except?

Accepted Answer

Stimulating insulin release from the pancreas

Answer

Promoting glycolysis

Answer

Inhibiting gluconeogenesis

Answer

Enhancing insulin binding to its receptors

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?