Endocrine Pharmacology Practice Questions

Q: A drug used in the management of osteoporosis has the mechanism of action depicted in the accompanying figure. What is the likely identity of this drug?

Denosumab. ***Denosumab*** - **Monoclonal antibody** that specifically blocks **RANKL** (Receptor Activator of Nuclear factor Kappa-B Ligand) from binding to **RANK** receptors on osteoclast precursors. - This mechanism prevents **osteoclast formation and activation**, directly reducing bone resorption and increasing bone mineral density. *Teriparatide* - **PTH analog** with an **anabolic mechanism** that stimulates **osteoblast activity** and bone formation, rather than inhibiting RANKL. - Acts as a **bone-building agent** through intermittent dosing, promoting new bone matrix synthesis. *Alendronate* - **Bisphosphonate** that works by inhibiting **farnesyl pyrophosphate synthase** within osteoclasts, leading to osteoclast apoptosis. - Does not target the **RANKL-RANK pathway** but instead disrupts osteoclast metabolism through interference with the **mevalonate pathway**. *Estrogen* - Works through **multiple mechanisms** including upregulation of **OPG** (osteoprotegerin) and decreased **RANKL expression**, but is not a direct RANKL inhibitor. - Also has **receptor-mediated effects** on both osteoblasts and osteoclasts, making it less specific than targeted RANKL blockade.

Q: Metformin is NOT effective in lowering of blood sugar level in which of the following patients?

Non-diabetics. **Explanation:** The core mechanism of **Metformin** (a Biguanide) is that it acts as an **euglycemic agent**, not a hypoglycemic agent. It lowers blood glucose levels primarily by inhibiting hepatic gluconeogenesis and increasing peripheral insulin sensitivity. Crucially, it does **not** stimulate insulin secretion from pancreatic beta cells [1]. Therefore, in a non-diabetic individual with normal blood sugar levels, Metformin will not further lower the blood glucose, making it ineffective for inducing hypoglycemia. **Analysis of Options:** * **Non-diabetics (Correct):** Since Metformin does not increase insulin levels, it has no significant effect on blood glucose in healthy individuals. It only lowers elevated blood sugar toward normal levels. * **Obese diabetics:** Metformin is the first-line drug of choice here. It promotes modest weight loss and improves insulin resistance, which is the hallmark of obesity-related Type 2 Diabetes Mellitus (T2DM). * **Type 2 diabetics:** This is the primary indication for Metformin [2]. It effectively reduces HbA1c by suppressing hepatic glucose output. * **Diabetics not responding to sulfonylureas:** Metformin is often added as a second-line agent or used in patients who have "secondary failure" to sulfonylureas, as it works via a different, insulin-independent mechanism [1]. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** Metformin is the first-line treatment for T2DM. * **Mechanism:** Activates **AMP-activated protein kinase (AMPK)**. * **Side Effects:** Most common are GI upset (diarrhea/nausea); most serious is **Lactic Acidosis** (rare but fatal). * **Contraindication:** Avoid in patients with significant renal impairment (CrCl <30 mL/min) due to the risk of lactic acidosis. * **Vitamin Deficiency:** Long-term use can lead to **Vitamin B12 deficiency**.

Q: Which of the following does not cause insulin release?

Rosiglitazone. ### Explanation The key to answering this question lies in distinguishing between **Insulin Secretagogues** (drugs that stimulate insulin release) and **Insulin Sensitizers** (drugs that improve the body's response to existing insulin). #### 1. Why Rosiglitazone is the Correct Answer **Rosiglitazone** belongs to the **Thiazolidinedione (TZD)** class. Its primary mechanism of action is as a selective agonist for the nuclear receptor **PPAR-γ** (Peroxisome Proliferator-Activated Receptor gamma). It works by increasing the transcription of genes involved in glucose metabolism, thereby **increasing insulin sensitivity** in peripheral tissues (adipose, muscle, and liver). It does **not** act on the pancreatic beta cells to stimulate insulin secretion; hence, it does not cause hypoglycemia when used as monotherapy. #### 2. Why the Other Options are Incorrect * **Glimepiride and Tolbutamide:** These are **Sulfonylureas** (2nd and 1st generation, respectively). They stimulate insulin release by binding to the **SUR1 subunit** of the ATP-sensitive K⁺ channels in pancreatic beta cells, causing channel closure, depolarization, and subsequent calcium influx. * **Nateglinide:** This is a **Meglitinide/Phenylalanine derivative**. Like sulfonylureas, it acts as an insulin secretagogue by closing ATP-sensitive K⁺ channels, though it has a faster onset and shorter duration of action (primarily targeting postprandial glucose). #### 3. NEET-PG High-Yield Pearls * **Insulin Secretagogues:** Sulfonylureas and Meglitinides. These carry a high risk of **hypoglycemia** and **weight gain**. * **Insulin Sensitizers:** Biguanides (Metformin) and TZDs (Rosiglitazone, Pioglitazone). * **TZD Side Effects:** Weight gain (due to fluid retention and adipogenesis), edema, and increased risk of bone fractures. * **Contraindication:** Rosiglitazone is generally avoided in patients with **NYHA Class III/IV Heart Failure** due to fluid overload risks.

Q: A 29-year-old male patient presents to the OPD with a 10-year history of coarse facial features and progressive enlargement of the hands and feet. Laboratory evaluation revealed elevated IGF-1 and non-suppressible growth hormone levels after the 75 g glucose challenge test. A diagnosis of acromegaly is made. Which of the following drugs is preferred for the management of this patient?

Lanreotide depot formulation. ***Lanreotide depot formulation***- This is a long-acting **somatostatin analog (SSA)** that binds to somatostatin receptors on the pituitary adenoma, effectively inhibiting the secretion of **growth hormone (GH)**.- SSAs, including lanreotide and **octreotide**, are considered the first-line medical therapy for acromegaly, especially when surgery fails or is contraindicated, as they control both GH and **IGF-1** levels.*Terlipressin*- *Terlipressin* is primarily used for the treatment of **bleeding esophageal varices** in patients with portal hypertension, as it acts as a **vasopressin analog** causing splanchnic vasoconstriction.- It has no therapeutic role in controlling sustained GH hypersecretion or managing the pituitary tumor responsible for **acromegaly**.*Ketoconazole*- *Ketoconazole* is primarily an **antifungal agent** but is occasionally used to inhibit **steroid biosynthesis** in conditions like **Cushing's syndrome** due to its effect on P450 enzymes.- It does not affect the production or secretion of **growth hormone** from the somatotropes and is therefore ineffective in treating **acromegaly**.*Leuprolide*- *Leuprolide* is a **Gonadotropin-Releasing Hormone (GnRH) agonist** used for conditions responsive to chemical castration, such as **prostate cancer** or **endometriosis**.- This agent targets the hypothalamic-pituitary-gonadal axis, having no clinical utility in directly suppressing the hypersecretion of **GH** in **acromegaly**.

Q: A 28-year-old woman is prescribed an oral contraceptive pill. The packaging shown in the image contains pills organized by weeks with different colored pills for Week 1, Week 2, and Week 3. What type of combined oral contraceptive preparation is this?

Triphasic combined OCP. ***Triphasic combined OCP*** - The image displays three distinct rows of pills for "Week 1", "Week 2", and "Week 3", and the text "all colored pills taking any white pills" implying a change in dosage or composition over the cycle. - **Triphasic pills** are designed to deliver varying levels of hormones (estrogen and progestin) in three sequential phases within the cycle to mimic the natural hormonal fluctuations. *Monophasic combined OCP* - **Monophasic pills** contain a constant dose of both estrogen and progestin throughout the active pill cycle. - The image clearly indicates different "weeks" and implies variation, which is characteristic of multiphasic, not monophasic, pills. *Emergency pill* - An **emergency contraceptive pill** is typically a single dose or two doses taken within a short timeframe after unprotected intercourse, not a 21-day pack with weekly indications. - Its purpose is to prevent pregnancy after sex, not for regular daily contraception over a menstrual cycle. *Biphasic combined OCP* - **Biphasic pills** have two different combinations of hormones per cycle, changing once during the 21-day active pill period. - The visual distinction of "Week 1", "Week 2", and "Week 3" strongly suggests three varying phases, making it triphasic rather than biphasic.

Q: Which of the following drugs will act on X to inhibit sugar absorption from the PCT of kidney?

Dapagliflozin. ***Dapagliflozin*** - The image shows glucose reabsorption in the **proximal tubule**, with 90% in the S1/S2 segments and 10% in the S3 segment. The "X" points to the **SGLT2 transporter** in the proximal tubule. - **Dapagliflozin** is an **SGLT2 inhibitor** that blocks glucose reabsorption, leading to increased glucose excretion in urine. - Used in **type 2 diabetes mellitus** and has cardiovascular and renal protective effects. *Furosemide* - A **loop diuretic** that acts on the **thick ascending limb of Loop of Henle**, not the proximal tubule. - Inhibits the **Na-K-2Cl cotransporter**, not involved in glucose reabsorption. *Hydrochlorothiazide* - A **thiazide diuretic** that acts on the **distal convoluted tubule (DCT)**. - Inhibits the **Na-Cl cotransporter**, not involved in glucose reabsorption. *Spironolactone* - A **potassium-sparing diuretic** that acts on the **collecting duct**. - Works as an **aldosterone antagonist**, not involved in glucose reabsorption.

Q: A 60-year-old post-menopausal woman presents with low back ache and pain in all legs muscles. Her lab reports show normal serum calcium, phosphate and normal serum alkaline phosphatase. For management of this condition, which of the following drugs is given by intranasal route?

Calcitonin. ***Calcitonin*** - Calcitonin is a hormone that inhibits **osteoclastic bone resorption** and can be administered via an **intranasal spray** for the management of osteoporosis. - While not a first-line treatment for osteoporosis, it's used in patients who cannot tolerate other therapies or for short-term pain relief in acute vertebral fractures. *Teriparatide* - **Teriparatide** is a recombinant form of **parathyroid hormone** that promotes **bone formation**. - It is administered via **subcutaneous injection**, not intranasally. *Zoledronate* - **Zoledronate** is a **bisphosphonate** that inhibits osteoclast activity and reduces bone turnover. - It is typically administered as an **intravenous infusion**, not intranasally. *Cinacalcet* - **Cinacalcet** is a **calcimimetic** drug that increases the sensitivity of calcium-sensing receptors on the parathyroid gland, thereby decreasing parathyroid hormone (PTH) secretion. - It is used to treat **secondary hyperparathyroidism** and **parathyroid carcinoma**, not directly for osteoporosis, and is administered **orally**.

Q: A primigravida at 38 weeks pregnancy was put on oxytocin drip in view of slow labour at the rate of 30 mIU/min by the newly appointed registrar. She complains of confusion and starts throwing fits. What electrolyte imbalance is expected to have happened in this case?

Hyponatremia. ***Hyponatremia*** - **Oxytocin** has an antidiuretic hormone (ADH)-like effect, leading to **water retention** and dilutional hyponatremia, especially when administered in large doses or with hypotonic solutions [1]. - Symptoms like **confusion** and **seizures (fits)** are classic signs of neurological impairment due to severe hyponatremia. *Hypokalemia* - While electrolyte imbalances can occur with oxytocin, **hypokalemia** is not typically associated with oxytocin's ADH-like actions or its direct effects on renal tubules. - Symptoms related to hypokalemia usually involve **muscle weakness** and cardiac arrhythmias, which are not the primary features here. *Hypocalcemia* - **Hypocalcemia** is more commonly associated with conditions like parathyroid dysfunction or vitamin D deficiency, not directly with oxytocin administration. - Symptoms would typically include **tetany**, muscle cramps, and paresthesias, not primarily confusion and seizures in this context. *Hypernatremia* - **Hypernatremia** would involve excess sodium or severe dehydration, which is contrary to the fluid retention effect of oxytocin and unlikely to cause seizures in this context. - Elevated sodium levels would typically present with symptoms of extreme thirst, lethargy, and dry mucous membranes.

Q: Which one of the following is correct regarding arginine vasopressin antagonist Tolvaptan?

It is an oral drug. ***It is an oral drug*** - **Tolvaptan** is an **orally active selective vasopressin V2-receptor antagonist** used in the treatment of hyponatremia. - Its oral bioavailability makes it convenient for long-term management of conditions like **syndrome of inappropriate antidiuretic hormone (SIADH)**. *It is useful in hypovolemic hyponatremia* - **Tolvaptan** is primarily used to treat **euvolemic** and **hypervolemic hyponatremia** by promoting **free water excretion**, which is not ideal in hypovolemic states where fluid status needs to be increased. - In **hypovolemic hyponatremia**, the primary treatment is **fluid resuscitation** with isotonic saline, not free water excretion. *It antagonises the V1 receptor* - **Tolvaptan** is a **selective V2-receptor antagonist**, meaning it specifically blocks the action of vasopressin at the V2 receptors in the renal collecting ducts. - Blocking **V1 receptors** would primarily affect smooth muscle contraction and platelet aggregation, which is not the therapeutic target for tolvaptan in hyponatremia. *It should be used for at least 1 year* - The duration of **Tolvaptan** treatment is variable and depends on the underlying cause of hyponatremia and the patient's response. - There is no standard recommendation for a minimum usage period of at least one year; treatment is typically continued as long as necessary and tolerated.

Question 1

A drug used in the management of osteoporosis has the mechanism of action depicted in the accompanying figure. What is the likely identity of this drug?

Accepted Answer

Denosumab

Answer

Teriparatide

Answer

Alendronate

Answer

Estrogen

Question 2

Metformin is NOT effective in lowering of blood sugar level in which of the following patients?

Accepted Answer

Non-diabetics

Answer

Obese diabetics

Answer

Type 2 diabetics

Answer

Diabetics not responding to sulfonylureas

Question 3

Which of the following does not cause insulin release?

Accepted Answer

Rosiglitazone

Answer

Nateglinide

Answer

Glimipiride

Answer

Tobutamide

Question 4

A 29-year-old male patient presents to the OPD with a 10-year history of coarse facial features and progressive enlargement of the hands and feet. Laboratory evaluation revealed elevated IGF-1 and non-suppressible growth hormone levels after the 75 g glucose challenge test. A diagnosis of acromegaly is made. Which of the following drugs is preferred for the management of this patient?

Accepted Answer

Lanreotide depot formulation

Answer

Leuprolide

Answer

Ketoconazole

Answer

Terlipressin

Question 5

A 55-year-old diabetic patient on metformin develops lactic acidosis after a contrast-enhanced CT scan. What is the mechanism by which metformin contributed to this complication?

Accepted Answer

Inhibition of mitochondrial complex I leading to increased anaerobic metabolism

Answer

Direct nephrotoxicity causing acute kidney injury

Answer

Stimulation of insulin secretion causing hypoglycemia

Answer

Increased hepatic gluconeogenesis

Question 6

A 28-year-old woman is prescribed an oral contraceptive pill. The packaging shown in the image contains pills organized by weeks with different colored pills for Week 1, Week 2, and Week 3. What type of combined oral contraceptive preparation is this?

Accepted Answer

Triphasic combined OCP

Answer

Monophasic combined OCP

Answer

Emergency pill

Answer

Biphasic combined OCP

Question 7

Which of the following drugs will act on X to inhibit sugar absorption from the PCT of kidney?

Accepted Answer

Dapagliflozin

Answer

Hydrochlorothiazide

Answer

Furosemide

Answer

Spironolactone

Question 8

A 60-year-old post-menopausal woman presents with low back ache and pain in all legs muscles. Her lab reports show normal serum calcium, phosphate and normal serum alkaline phosphatase. For management of this condition, which of the following drugs is given by intranasal route?

Accepted Answer

Calcitonin

Answer

Teriparatide

Answer

Cinacalcet

Answer

Zoledronate

Question 9

A primigravida at 38 weeks pregnancy was put on oxytocin drip in view of slow labour at the rate of 30 mIU/min by the newly appointed registrar. She complains of confusion and starts throwing fits. What electrolyte imbalance is expected to have happened in this case?

Accepted Answer

Hyponatremia

Answer

Hypokalemia

Answer

Hypocalcemia

Answer

Hypernatremia

Question 10

Which one of the following is correct regarding arginine vasopressin antagonist Tolvaptan?

Accepted Answer

It is an oral drug

Answer

It is useful in hypovolemic hyponatremia

Answer

It antagonises the V1 receptor

Answer

It should be used for at least 1 year

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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