Endocrine Pharmacology Practice Questions

Q: What is a common side effect of thiazolidinediones?

Water retention with weight gain. ### Explanation **Thiazolidinediones (TZDs)**, such as Pioglitazone and Rosiglitazone, are PPAR-γ (Peroxisome Proliferator-Activated Receptor gamma) agonists. They act primarily by increasing insulin sensitivity in peripheral tissues (adipose, muscle, and liver). **Why Option C is Correct:** The most characteristic side effect of TZDs is **fluid retention (edema) and weight gain**. This occurs because PPAR-γ receptors are also expressed in the collecting ducts of the nephron. Activation of these receptors leads to increased sodium and water reabsorption (via ENaC channels). This fluid overload can precipitate or worsen **congestive heart failure (CHF)**, making it a major contraindication in patients with NYHA Class III or IV heart failure. **Analysis of Incorrect Options:** * **A. Dysgeusia:** This (metallic taste) is a classic side effect of **Metformin**, not TZDs. * **B. Hypoglycemia:** TZDs are "euglycemics." Since they enhance the action of endogenous insulin rather than increasing insulin secretion, they rarely cause hypoglycemia when used as monotherapy. * **D. Anemia:** While mild hemodilutional anemia can occur due to fluid retention, it is not as clinically hallmark or frequently tested as weight gain and edema. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** PPAR-γ is a nuclear receptor; TZDs increase the expression of **GLUT-4** and adiponectin. * **Bone Health:** TZDs are associated with an increased risk of **fractures** (especially in women) due to decreased osteoblast differentiation. * **Bladder Cancer:** Pioglitazone has a controversial but noted association with an increased risk of bladder cancer (avoid in patients with active or past history of bladder cancer). * **Hepatotoxicity:** Troglitazone (the first TZD) was withdrawn due to severe liver injury; monitoring LFTs is still recommended for current TZDs.

Q: All of the following are used to treat hypercalcemia, EXCEPT:

D-penicillamine. **Explanation:** Hypercalcemia is a critical metabolic emergency requiring agents that either decrease bone resorption, increase renal excretion, or decrease intestinal absorption of calcium. **Why D-penicillamine is the correct answer:** D-penicillamine is a **chelating agent** primarily used in the treatment of **Wilson’s disease** (to remove copper), cystinuria, and severe rheumatoid arthritis. It has no clinical role in the management of hypercalcemia. **Analysis of incorrect options (Agents used in Hypercalcemia):** * **Corticosteroids (Option B):** These are particularly effective in hypercalcemia associated with **sarcoidosis, vitamin D intoxication, and lymphomas**. They work by decreasing the intestinal absorption of calcium and inhibiting the expression of 1-alpha-hydroxylase. * **Bisphosphonates (Option C):** (e.g., Zoledronate, Pamidronate) These are the **drugs of choice** for malignancy-associated hypercalcemia. They act by inhibiting osteoclast activity, thereby reducing bone resorption. * **Mithramycin (Plicamycin) (Option D):** This is a cytotoxic antibiotic that inhibits osteoclast function. While effective for refractory hypercalcemia, its use is limited due to significant toxicity (nephrotoxicity and thrombocytopenia). **NEET-PG High-Yield Pearls:** * **Immediate Management:** The first step in severe hypercalcemia is always **aggressive IV hydration with Normal Saline**, followed by loop diuretics (Furosemide) to promote "calciuresis." * **Calcitonin:** Used for rapid reduction of calcium (works within hours) but is limited by **tachyphylaxis** (diminishing effect after 48 hours). * **Cinacalcet:** A calcimimetic used specifically for hypercalcemia in secondary hyperparathyroidism or parathyroid carcinoma. * **Denosumab:** A RANKL inhibitor used when bisphosphonates are contraindicated or ineffective.

Q: What is the recommended replacement dose of thyroxine?

0.1 - 0.2 mg. The correct answer is **A. 0.1 - 0.2 mg**. ### **Explanation** The goal of thyroxine (L-thyroxine) replacement therapy in hypothyroidism is to restore the patient to a euthyroid state. The standard daily maintenance dose for an average adult is approximately **1.6 µg/kg body weight**. For a typical adult weighing 60–70 kg, this calculates to roughly **100–150 µg (0.1 to 0.15 mg)** per day. Therefore, the range of **0.1 – 0.2 mg** (100–200 µg) is the clinically accepted standard for full replacement. ### **Analysis of Incorrect Options** * **B (0.3 - 0.4 mg):** This dose is excessively high for standard replacement and would likely lead to iatrogenic hyperthyroidism, increasing the risk of atrial fibrillation and osteoporosis. * **C & D (1 - 4 mg):** These doses are massive and potentially fatal. They are far beyond the physiological requirements of the human body. ### **High-Yield NEET-PG Pearls** * **Monitoring:** The best indicator for adjusting the dose in primary hypothyroidism is the **Serum TSH level**. (Target: 0.5–2.5 mIU/L). * **Administration:** Thyroxine should be taken on an **empty stomach** (30–60 minutes before breakfast) because food, calcium, and iron supplements significantly decrease its absorption. * **Special Populations:** * **Elderly/Cardiac patients:** Start with a lower dose (12.5–25 µg) to avoid precipitating angina or myocardial infarction. * **Pregnancy:** Thyroxine requirements typically **increase** by 30–50% due to increased TBG levels. * **Drug of Choice:** Levothyroxine (T4) is preferred over Liothyronine (T3) due to its longer half-life (7 days), consistent blood levels, and peripheral conversion to T3.

Q: Which of the following drugs is an alpha-glucosidase inhibitor?

Miglitol. **Explanation:** **Alpha-glucosidase inhibitors (AGIs)**, such as **Miglitol** and **Acarbose**, act locally in the small intestine. They competitively inhibit the enzyme alpha-glucosidase, which is responsible for breaking down complex carbohydrates (disaccharides and oligosaccharides) into absorbable monosaccharides like glucose. By delaying carbohydrate absorption, these drugs primarily reduce **post-prandial hyperglycemia**. **Analysis of Options:** * **Miglitol (Correct):** It is a potent AGI. Unlike Acarbose, Miglitol is almost completely absorbed from the gut but is not metabolized and is excreted unchanged by the kidneys. * **Pioglitazone (Incorrect):** Belongs to the **Thiazolidinedione (TZD)** class. It acts as a PPAR-gamma agonist, increasing peripheral insulin sensitivity (primarily in adipose tissue and muscle). * **Metformin (Incorrect):** A **Biguanide** and the first-line drug for Type 2 Diabetes. Its primary mechanism is the activation of AMP-activated protein kinase (AMPK), which suppresses hepatic gluconeogenesis. * **Nateglinide (Incorrect):** A **Meglitinide analogue** (Glinide). It acts as a short-acting insulin secretagogue by closing ATP-sensitive K+ channels in pancreatic beta cells. **High-Yield Clinical Pearls for NEET-PG:** * **Side Effects:** The most common side effects of AGIs are GI-related: flatulence, bloating, and diarrhea (due to fermentation of undigested carbohydrates in the colon). * **Hypoglycemia Management:** If a patient on an AGI experiences hypoglycemia (usually due to concurrent sulfonylurea use), they must be treated with **pure glucose (dextrose)**, not sucrose (cane sugar), because AGIs block the breakdown of sucrose. * **Weight Neutrality:** AGIs are generally weight-neutral and do not cause hypoglycemia when used as monotherapy.

Q: Hydrocortisone acts as an anti-inflammatory agent because of the induction of the synthesis of which of the following proteins?

Annexin A1. **Explanation:** The anti-inflammatory action of glucocorticoids like **Hydrocortisone** is primarily mediated through the regulation of gene expression. When hydrocortisone binds to its intracellular glucocorticoid receptor (GR), the complex translocates to the nucleus and induces the transcription of specific anti-inflammatory proteins. **Annexin A1 (also known as Lipocortin-1)** is the most significant of these induced proteins. Its primary mechanism is the **inhibition of Phospholipase A2 (PLA2)**. By inhibiting PLA2, Annexin A1 prevents the release of arachidonic acid from the cell membrane, thereby blocking the synthesis of both prostaglandins (via the COX pathway) and leukotrienes (via the LOX pathway). This dual inhibition is what makes steroids more potent anti-inflammatory agents than NSAIDs. **Analysis of Incorrect Options:** * **A. Heat shock protein 90 (hsp90):** This protein acts as a "chaperone" that keeps the glucocorticoid receptor in an inactive state in the cytoplasm. Hydrocortisone causes the *release* of hsp90, not its synthesis. * **B. Inhibin:** This is a peptide hormone produced by the gonads to inhibit FSH secretion; it has no role in the mechanism of corticosteroids. * **C. Transcortin:** Also known as Corticosteroid Binding Globulin (CBG), this is the transport protein for cortisol in the blood. It is synthesized in the liver, not induced by hydrocortisone as part of its anti-inflammatory effect. **High-Yield Clinical Pearls for NEET-PG:** * **Genomic vs. Non-genomic:** Annexin A1 induction is a **genomic effect** (takes time). * **NF-κB Inhibition:** Glucocorticoids also suppress inflammation by inhibiting the transcription factor NF-κB, which reduces the production of pro-inflammatory cytokines (IL-1, TNF-α). * **Metabolic Side Effects:** Remember that while they suppress inflammation, they induce enzymes for gluconeogenesis, leading to hyperglycemia (Steroid Diabetes).

Q: What is the corticosteroid of choice in acute adrenal insufficiency?

Hydrocortisone. **Explanation:** **1. Why Hydrocortisone is the Correct Answer:** In acute adrenal insufficiency (Addisonian crisis), there is a life-threatening deficiency of both **glucocorticoids** (cortisol) and **mineralocorticoids** (aldosterone). Hydrocortisone is the drug of choice because it possesses significant activity at both receptors (Glucocorticoid:Mineralocorticoid potency ratio of **1:1**). Its rapid onset of action when given intravenously and its ability to mimic the body’s natural cortisol secretion make it ideal for stabilizing hemodynamics and correcting electrolyte imbalances (hyponatremia and hyperkalemia) simultaneously. **2. Analysis of Incorrect Options:** * **Fludrocortisone (A):** This is a potent mineralocorticoid used for long-term maintenance therapy. It is not used in acute crises because it lacks sufficient glucocorticoid activity and is only available in oral formulations. * **Dexamethasone (C):** While highly potent as a glucocorticoid, it has **zero mineralocorticoid activity**. It is only used in an emergency if the diagnosis of adrenal insufficiency is not yet confirmed, as it does not interfere with the measurement of serum cortisol levels (ACTH stimulation test). * **Prednisolone (D):** This has intermediate glucocorticoid potency but very low mineralocorticoid activity. It is more suitable for chronic inflammatory conditions rather than acute replacement. **3. High-Yield Clinical Pearls for NEET-PG:** * **Standard Crisis Dose:** 100 mg IV bolus of Hydrocortisone, followed by 100–200 mg every 24 hours. * **Diagnosis:** If the diagnosis is unknown, use **Dexamethasone** to allow for immediate ACTH stimulation testing. * **Maintenance:** Once stable, patients are switched to oral Hydrocortisone (divided doses) plus Fludrocortisone. * **Potency Ratio:** Remember that Hydrocortisone is the pharmaceutical equivalent of endogenous Cortisol.

Q: Which of the following agents is not used in the management of erectile dysfunction?

Phenylephrine. ### Explanation The management of erectile dysfunction (ED) focuses on increasing blood flow to the corpora cavernosa through vasodilation. **Phenylephrine** is the correct answer because it is a selective **$\alpha_1$-adrenergic agonist** that causes potent **vasoconstriction**. In the context of male reproductive health, phenylephrine is actually the drug of choice for treating **priapism** (a prolonged, painful erection), as it constricts the cavernous arteries to reduce blood inflow. **Analysis of Incorrect Options:** * **Vardenafil (Option B):** A potent **PDE-5 inhibitor**. It prevents the degradation of cGMP, leading to smooth muscle relaxation and increased blood flow. It is a first-line oral treatment for ED. * **Alprostadil (Option D):** This is a synthetic analogue of **PGE1**. It increases cAMP levels, causing direct vasodilation. It is administered via intracavernosal injection or intraurethral pellets (MUSE). * **PGE2 (Option A):** While PGE1 (Alprostadil) is more commonly used, PGE2 (Dinoprostone) also possesses vasodilatory properties and has historically been used in intracavernosal "cocktails" for ED, though it is now less common than PGE1. **NEET-PG High-Yield Pearls:** * **PDE-5 Inhibitors:** Sildenafil, Vardenafil, and Tadalafil (longest acting, "The Weekend Pill"). * **Contraindication:** Never co-administer PDE-5 inhibitors with **Nitrates**, as this can lead to life-threatening hypotension. * **Priapism Treatment:** If phenylephrine fails, surgical shunting may be required. * **Alprostadil:** Also used to maintain a **Patent Ductus Arteriosus (PDA)** in neonates with cyanotic heart disease.

Q: What is the best drug for chronic gout in a patient with renal impairment?

Allopurinol. **Explanation:** **1. Why Allopurinol is the Correct Answer:** Allopurinol is a **Xanthine Oxidase Inhibitor** that reduces the production of uric acid. In chronic gout management, it is considered the first-line urate-lowering therapy (ULT) regardless of renal function. While allopurinol metabolites are excreted renally, it remains the drug of choice in renal impairment because its dose can be safely **titrated downwards** (starting at ≤100 mg/day) to achieve target serum urate levels while monitoring for toxicity. Unlike uricosurics, its efficacy does not depend on renal clearance of uric acid. **2. Why the Other Options are Incorrect:** * **Naproxen (NSAID):** NSAIDs are used for acute gouty attacks, not chronic management. Furthermore, they are generally **contraindicated** in significant renal impairment due to the risk of acute kidney injury and fluid retention. * **Probenecid & Sulfinpyrazone (Uricosurics):** These drugs work by inhibiting the reabsorption of uric acid in the proximal tubule. They are **ineffective** when the Glomerular Filtration Rate (GFR) is low (typically <30–50 mL/min) because they cannot reach their site of action in the tubular lumen. They also increase the risk of uric acid nephrolithiasis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Febuxostat:** Another Xanthine Oxidase Inhibitor; it is metabolized by the liver and is a preferred alternative if allopurinol is not tolerated in renal patients. * **HLA-B*5801:** Testing for this allele is recommended before starting Allopurinol in high-risk populations (e.g., Han Chinese, Thai) to prevent **Stevens-Johnson Syndrome/TEN**. * **Acute Attack Prophylaxis:** When starting Allopurinol, always co-administer low-dose colchicine or NSAIDs for 3–6 months to prevent "mobilization flares."

Question 1

What is a common side effect of thiazolidinediones?

Accepted Answer

Water retention with weight gain

Answer

Dysgeusia

Answer

Hypoglycemia

Answer

Anemia

Question 2

All of the following are used to treat hypercalcemia, EXCEPT:

Accepted Answer

D-penicillamine

Answer

Corticosteroid

Answer

Bisphosphonate

Answer

Mithramycin

Question 3

Which of the following has the least mineralocorticoid activity?

Accepted Answer

Methylprednisolone

Answer

Cortisol

Answer

Prednisolone

Answer

Fludrocortisone

Question 4

In the treatment of congenital adrenal hyperplasia due to lack of 21 β–hydroxylase, what is the purpose of administering a synthetic glucocorticoid?

Accepted Answer

Suppression of ACTH secretion

Answer

Inhibition of aldosterone synthesis

Answer

Prevention of hypoglycemia

Answer

Recovery of normal immune function

Question 5

What is the recommended replacement dose of thyroxine?

Accepted Answer

0.1 - 0.2 mg

Answer

0.3 - 0.4 mg

Answer

1 - 2 mg

Answer

3 - 4 mg

Question 6

Which of the following drugs is an alpha-glucosidase inhibitor?

Accepted Answer

Miglitol

Answer

Pioglitazone

Answer

Metformin

Answer

Nateglinide

Question 7

Hydrocortisone acts as an anti-inflammatory agent because of the induction of the synthesis of which of the following proteins?

Accepted Answer

Annexin A1

Answer

Heat shock protein 90

Answer

Inhibin

Answer

Transcortin

Question 8

What is the corticosteroid of choice in acute adrenal insufficiency?

Accepted Answer

Hydrocortisone

Answer

Fludrocortisone

Answer

Dexamethasone

Answer

Prednisolone

Question 9

Which of the following agents is not used in the management of erectile dysfunction?

Accepted Answer

Phenylephrine

Answer

PGE2

Answer

Vardenafil

Answer

Alprostadil

Question 10

What is the best drug for chronic gout in a patient with renal impairment?

Accepted Answer

Allopurinol

Answer

Naproxen

Answer

Probenecid

Answer

Sulfinpyrazone

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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