Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 111: What is the major adverse effect of glucocorticoids, especially in children?

A. Hyperkalemia
B. Hypoglycemia
C. Muscular weakness
D. Posterior subcapsular cataract (Correct Answer)

Explanation: **Explanation:** Glucocorticoids have widespread systemic effects, and their ocular toxicity is a high-yield topic for NEET-PG. **Why Option D is Correct:** **Posterior subcapsular cataract (PSC)** is a classic and major adverse effect of long-term glucocorticoid therapy. While it can occur in adults, **children are significantly more susceptible** to this complication. The mechanism involves the binding of steroids to lens proteins, leading to protein aggregation and lens opacification. Unlike steroid-induced glaucoma (which may resolve), steroid-induced cataracts are usually **irreversible** and often require surgical intervention. **Analysis of Incorrect Options:** * **A. Hyperkalemia:** Glucocorticoids have inherent mineralocorticoid activity (especially cortisol and prednisolone), which promotes sodium retention and potassium excretion. Therefore, they cause **hypokalemia**, not hyperkalemia. * **B. Hypoglycemia:** Glucocorticoids are "diabetogenic." They stimulate gluconeogenesis and decrease peripheral glucose uptake, leading to **hyperglycemia** (Steroid-induced Diabetes). * **C. Muscular weakness:** While "Steroid Myopathy" does occur due to muscle wasting (proteolysis), it typically affects the **proximal** muscles of the limbs. However, in the context of pediatric-specific major adverse effects, PSC is a more distinct and frequently tested ocular complication. **NEET-PG High-Yield Pearls:** * **Ocular triad of steroids:** Posterior subcapsular cataract, increased intraocular pressure (glaucoma), and secondary ocular infections (fungal/viral). * **Growth Suppression:** In children, the most significant systemic concern is the suppression of the **growth plate** and GH inhibition, leading to stunted growth. * **Alternate-day therapy:** This strategy is often used in children to minimize growth suppression and HPA-axis suppression.

Question 112: Which one of the following does NOT act by increasing insulin secretion?

A. Glyburide
B. Repaglinide
C. Tolbutamide
D. Biguanide (Correct Answer)

Explanation: ### Explanation The correct answer is **D. Biguanide (e.g., Metformin)**. The fundamental distinction in oral hypoglycemic agents is between **insulin secretagogues** (which force the pancreas to release more insulin) and **insulin sensitizers** (which improve how the body uses existing insulin). **1. Why Biguanide is the correct answer:** Biguanides (Metformin) do **not** stimulate the pancreas to secrete insulin. Instead, they act primarily by: * **Inhibiting hepatic gluconeogenesis** (decreasing glucose production by the liver). * Activating **AMP-activated protein kinase (AMPK)**. * Increasing peripheral glucose uptake and utilization in skeletal muscles (improving insulin sensitivity). Because they do not increase insulin levels, they carry a much lower risk of hypoglycemia compared to secretagogues. **2. Why the other options are incorrect:** * **A. Glyburide & C. Tolbutamide:** These are **Sulfonylureas** (Second and First generation, respectively). They act by binding to the **SUR1 subunit** of the ATP-sensitive $K^+$ channels on pancreatic $\beta$-cells. This causes channel closure, depolarization, calcium influx, and subsequent exocytosis of insulin. * **B. Repaglinide:** This is a **Meglitinide** (Glinide). Although it binds to a different site than sulfonylureas, its mechanism is identical: it closes ATP-sensitive $K^+$ channels to stimulate insulin release. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** Metformin is the first-line drug for Type 2 Diabetes Mellitus (T2DM) and is "weight neutral" or promotes weight loss. * **Side Effects:** The most serious (though rare) side effect of Metformin is **Lactic Acidosis**; the most common are GI upsets. * **Contraindication:** Avoid Metformin in patients with significant renal impairment (CrCl <30 ml/min) due to the risk of lactate accumulation. * **Secretagogues & Weight:** Sulfonylureas and Meglitinides typically cause **weight gain** and carry a high risk of **hypoglycemia**.

Question 113: Hypokalemic paralysis is a side effect of which of the following?

A. Gossypol (Correct Answer)
B. DMPA
C. Testosterone enanthate
D. Cyproterone acetate

Explanation: **Gossypol** is a polyphenolic compound derived from the cotton plant (*Gossypium*) used as a male oral contraceptive. Its primary mechanism involves inhibiting sperm motility and spermatogenesis by interfering with mitochondrial enzymes and lactate dehydrogenase-X [1]. **Why Gossypol is the correct answer:** The most significant and clinically relevant side effect of Gossypol is **hypokalemia**, which can lead to **hypokalemic periodic paralysis** [1]. This occurs because Gossypol causes renal potassium wasting by inhibiting the Na+-K+ ATPase pump and affecting renal tubular function. This side effect is often irreversible in a small percentage of users, which has limited its clinical adoption as a mainstream contraceptive [1]. **Analysis of Incorrect Options:** * **B. DMPA (Depot Medroxyprogesterone Acetate):** An injectable progestogen-only contraceptive. Common side effects include weight gain, menstrual irregularities, and a reversible decrease in bone mineral density (BMD), but not hypokalemia. * **C. Testosterone enanthate:** An androgen used for replacement therapy or male contraception. Side effects include acne, erythrocytosis (increased hematocrit), and suppression of HDL; it does not cause potassium depletion. * **D. Cyproterone acetate:** An anti-androgen with progestogenic activity. It is used in treating hirsutism and prostate cancer. Its main side effects include hepatotoxicity and fatigue, not hypokalemic paralysis. **High-Yield Clinical Pearls for NEET-PG:** * **Gossypol's "Rule of 3":** It causes **Hypokalemia**, **Irreversibility** (in 10-20% of cases), and **Infertility**. * **Mechanism:** It acts as a non-hormonal male contraceptive. * **Other side effects:** Edema and digestive disturbances. * **Note:** Due to the risk of permanent infertility and life-threatening hypokalemia, it is currently not FDA-approved.

Question 114: What is the most specific pharmacological agent for treating erectile disorder in males?

A. Sildenafil (Correct Answer)
B. Diazepam
C. Fluoxetine
D. Zolpidem

Explanation: **Explanation:** **Sildenafil** is the correct answer because it is a selective **Phosphodiesterase-5 (PDE-5) inhibitor**. In the presence of sexual stimulation, nitric oxide (NO) is released, which increases levels of cyclic Guanosine Monophosphate (cGMP) in the corpus cavernosum. cGMP causes smooth muscle relaxation and vasodilation, leading to an erection. Sildenafil prevents the breakdown of cGMP by inhibiting the PDE-5 enzyme, thereby enhancing and prolonging the erectile response. **Analysis of Incorrect Options:** * **Diazepam:** A Benzodiazepine used primarily for anxiety and muscle relaxation. It has no direct effect on the vascular mechanisms of erection and may actually cause sexual dysfunction as a side effect. * **Fluoxetine:** An SSRI antidepressant. A common side effect of SSRIs is sexual dysfunction (delayed ejaculation or decreased libido), making it inappropriate for treating erectile disorder. * **Zolpidem:** A non-benzodiazepine hypnotic used for insomnia. It does not influence the nitric oxide-cGMP pathway. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindication:** Never co-administer Sildenafil with **Nitrates** (e.g., Nitroglycerin) as it can lead to severe, life-threatening hypotension. * **Side Effects:** Common side effects include headache, flushing, and **blue-tinted vision** (cyanopsia) due to weak inhibition of PDE-6 in the retina. * **Other Uses:** Sildenafil is also FDA-approved for the treatment of **Pulmonary Arterial Hypertension (PAH)**. * **Alprostadil:** A PGE1 analogue used as a second-line treatment (intracavernosal injection) for erectile dysfunction.

Question 115: In a patient on long-term steroid therapy, what precaution should be taken prior to tooth extraction?

A. Stop steroids before extraction
B. Administer additional steroids (Correct Answer)
C. Increase antibiotic coverage
D. Continue steroids as usual

Explanation: **Explanation:** The correct answer is **Administer additional steroids** (Option B). **1. Why it is correct:** Patients on long-term steroid therapy (typically >5 mg prednisolone equivalent for >2 weeks) experience **Hypothalamic-Pituitary-Adrenal (HPA) axis suppression**. Under normal conditions, the body increases cortisol production during physical stress (like surgery or trauma) to maintain hemodynamic stability. In these patients, the suppressed adrenal glands cannot produce this "stress dose" of cortisol, putting the patient at risk of a life-threatening **Adrenal Crisis** (acute hypotension, shock, and collapse). Therefore, supplemental "stress doses" of steroids are required prior to stressful procedures like tooth extraction. **2. Why other options are incorrect:** * **Option A:** Stopping steroids is dangerous as it can precipitate withdrawal symptoms and immediate adrenal crisis. * **Option C:** While antibiotics may be used to prevent infection in immunocompromised patients, they do not address the physiological risk of adrenal insufficiency. * **Option D:** Continuing the usual dose is insufficient because the baseline dose does not account for the increased metabolic demand required to handle surgical stress. **3. High-Yield Clinical Pearls for NEET-PG:** * **Rule of Twos:** HPA suppression should be suspected if a patient has taken **20 mg** of prednisone (or equivalent) for **2 weeks**, within the last **2 years**. * **Dosing:** For minor oral surgery (e.g., simple extraction), a common regimen is 5–10 mg of prednisolone or 25 mg of hydrocortisone pre-operatively. * **Steroid Potency:** Remember the potency ratio for exams: **Hydrocortisone (1) < Prednisolone (4) < Dexamethasone (25).** * **Adrenal Crisis Presentation:** Unexplained hypotension that does not respond to fluids or vasopressors but responds to IV hydrocortisone.

Question 116: All of the following statements about alpha-glucosidase inhibitors are true EXCEPT?

A. Reduces intestinal absorption of carbohydrates
B. Effective in both type 1 and type 2 diabetes
C. Hypoglycemia is a common and serious side effect (Correct Answer)
D. Can be used with other oral hypoglycemic agents

Explanation: **Explanation:** Alpha-glucosidase inhibitors (AGIs), such as **Acarbose, Miglitol, and Voglibose**, act by reversibly inhibiting the enzyme alpha-glucosidase in the brush border of the small intestine. This enzyme is responsible for breaking down complex polysaccharides into absorbable monosaccharides (glucose). **Why Option C is the correct answer (The False Statement):** AGIs do not stimulate insulin secretion; they merely delay glucose absorption. Therefore, when used as **monotherapy, they do not cause hypoglycemia**. However, if hypoglycemia occurs because of concurrent use with sulfonylureas or insulin, it must be treated with **pure glucose (dextrose)** and not sucrose (cane sugar), as AGIs will block the breakdown and absorption of sucrose. **Analysis of other options:** * **Option A:** This is the primary mechanism. By delaying the digestion of carbohydrates, AGIs reduce post-prandial glucose excursions. * **Option B:** While primarily used in Type 2 Diabetes, AGIs can be used as an adjunct in Type 1 Diabetes to smooth out post-meal glucose spikes. * **Option C:** AGIs are frequently combined with Metformin, Sulfonylureas, or Insulin to achieve better glycemic control. **High-Yield NEET-PG Pearls:** * **Side Effects:** The most common side effects are GI-related (flatulence, diarrhea, abdominal bloating) due to the fermentation of undigested carbohydrates by colonic bacteria. * **Contraindications:** Inflammatory Bowel Disease (IBD), intestinal obstruction, or chronic intestinal diseases. * **Voglibose:** Often preferred over Acarbose due to a better side-effect profile (less flatulence). * **Clinical Utility:** Best suited for patients with high **post-prandial hyperglycemia**.

Question 117: All of the following statements about Octreotide are true except?

A. It is effective orally (Correct Answer)
B. It is used for the treatment of acromegaly
C. It can be used for the treatment of secretory diarrhea
D. It can be used in portal hypertension

Explanation: **Explanation:** **1. Why Option A is the correct answer (The "Except" statement):** Octreotide is a synthetic long-acting analog of **Somatostatin**. Like most peptide hormones, it is rapidly degraded by gastric enzymes and has poor bioavailability if taken enterally. Therefore, it is **not effective orally** and must be administered parenterally (Subcutaneous or Intravenous). While an oral formulation (Mycapssa) was recently FDA-approved for specific maintenance in acromegaly, in the context of standard pharmacology and NEET-PG patterns, Octreotide is classically considered a parenteral drug. **2. Analysis of other options:** * **Option B (Acromegaly):** Octreotide is a potent inhibitor of Growth Hormone (GH). It is more potent and has a longer half-life than natural somatostatin, making it a first-line medical therapy for acromegaly. * **Option C (Secretory Diarrhea):** It inhibits the release of various gastrointestinal hormones (like VIP, serotonin, and gastrin). It is highly effective in treating secretory diarrhea associated with **Carcinoid syndrome** and **VIPomas**. * **Option D (Portal Hypertension):** Octreotide causes **splanchnic vasoconstriction** by inhibiting the release of glucagon and other vasodilatory peptides. This reduces portal blood flow, making it a drug of choice for managing **acute variceal bleeding**. **Clinical Pearls for NEET-PG:** * **Mechanism:** Somatostatin analog; binds to SSTR-2 and SSTR-5 receptors. * **Side Effects:** Most common are GI-related (nausea, abdominal pain). A high-yield side effect is the formation of **gallstones (cholelithiasis)** due to inhibition of cholecystokinin (CCK) and gallbladder contractility. * **Other Uses:** Used in "dumping syndrome" post-gastric surgery and for localizing neuroendocrine tumors (OctreoScan).

Question 118: Glucose intolerance is seen with all the following medications except?

A. Thiazide diuretics
B. Beta blockers
C. ACE inhibitors (Correct Answer)
D. Phenytoin

Explanation: **Explanation:** The correct answer is **ACE inhibitors (Option C)**. Unlike the other drugs listed, ACE inhibitors (and ARBs) actually **improve insulin sensitivity** and are considered renoprotective in diabetic patients. They increase levels of bradykinin, which enhances glucose uptake in skeletal muscles, and improve pancreatic blood flow, thereby reducing the risk of new-onset type 2 diabetes. **Why the other options are incorrect:** * **Thiazide Diuretics (A):** These are notorious for causing hyperglycemia. They inhibit insulin release from the pancreas (partly due to hypokalemia, as insulin secretion is K+ dependent) and decrease peripheral glucose utilization. * **Beta Blockers (B):** Non-selective beta-blockers (like Propranolol) inhibit $\beta_2$-mediated insulin release and decrease peripheral insulin sensitivity. Crucially, they also mask the autonomic warning symptoms of hypoglycemia (tachycardia, tremors), making them risky for diabetics. * **Phenytoin (D):** This anticonvulsant directly inhibits the release of insulin from the pancreas, leading to "Phenytoin-induced hyperglycemia." **High-Yield Clinical Pearls for NEET-PG:** 1. **Drugs causing Hyperglycemia (Glucose Intolerance):** Remember the mnemonic **"S-P-I-T"**: **S**teroids, **P**henytoin/Protease Inhibitors, **I**mmunosuppressants (Tacrolimus/Cyclosporine), and **T**hiazides. 2. **Atypical Antipsychotics:** Olanzapine and Clozapine carry the highest risk of metabolic syndrome and new-onset diabetes. 3. **Statins:** While beneficial for cardiovascular health, high-dose statins are associated with a slight increase in the risk of developing type 2 diabetes. 4. **Drug of Choice:** ACE inhibitors are the preferred antihypertensives in diabetic patients with proteinuria/albuminuria.

Question 119: Which drug inhibits the binding of RANKL to its receptor (RANK) in osteoporosis?

A. Teriparatide
B. Alendronate
C. Denosumab (Correct Answer)
D. Estrogen

Explanation: **Explanation:** **Denosumab** is a fully human monoclonal antibody that targets and binds to **RANKL** (Receptor Activator of Nuclear Factor kappa-B Ligand). Under normal physiological conditions, RANKL is secreted by osteoblasts and binds to RANK receptors on osteoclast precursors, triggering their maturation and activation. By inhibiting this binding, Denosumab prevents osteoclast formation and activity, thereby decreasing bone resorption and increasing bone mineral density (BMD). **Analysis of Incorrect Options:** * **A. Teriparatide:** A recombinant formulation of PTH (1-34). Unlike other agents, it is **anabolic**; it stimulates osteoblastic activity and new bone formation when given in intermittent pulses. * **B. Alendronate:** A **Bisphosphonate**. It works by depositing into the bone matrix and inducing apoptosis of osteoclasts once they ingest the drug. It does not interfere with the RANKL-RANK pathway directly. * **C. Estrogen:** Reduces bone resorption by suppressing the transcription of bone-resorbing cytokines (like IL-1, IL-6, and TNF) and increasing the production of **Osteoprotegerin (OPG)**, a natural decoy receptor for RANKL. **High-Yield NEET-PG Pearls:** * **Denosumab Administration:** Given as a subcutaneous injection once every 6 months. * **Osteoprotegerin (OPG):** Denosumab essentially mimics the physiological function of OPG. * **Side Effects:** Denosumab is associated with an increased risk of infections (due to RANKL's role in the immune system) and, rarely, osteonecrosis of the jaw (ONJ). * **Drug of Choice:** Bisphosphonates remain the first-line treatment for most osteoporosis cases; Denosumab is often reserved for patients with renal impairment or those who fail bisphosphonate therapy.

Question 120: Which of the following antidiabetic drugs can cause vitamin B12 deficiency?

A. Glipizide
B. Acarbose
C. Metformin (Correct Answer)
D. Pioglitazone

Explanation: **Explanation:** **Metformin (Option C)** is the correct answer. It is the first-line drug for Type 2 Diabetes Mellitus (T2DM) but is well-known to cause **Vitamin B12 deficiency** in approximately 10–30% of patients on long-term therapy. **Mechanism of B12 Deficiency:** Metformin interferes with the **calcium-dependent absorption** of the Vitamin B12-Intrinsic Factor (IF) complex in the terminal ileum. Since the binding of this complex to ileal receptors requires calcium, Metformin’s effect on the cell membrane potential inhibits this process. This can lead to megaloblastic anemia and peripheral neuropathy, which is often misdiagnosed as diabetic neuropathy. **Why other options are incorrect:** * **Glipizide (A):** A second-generation Sulfonylurea. Its primary side effects are hypoglycemia and weight gain; it does not affect B12 levels. * **Acarbose (B):** An Alpha-glucosidase inhibitor. It acts locally in the gut to delay carbohydrate absorption. Common side effects are GI-related (flatulence, diarrhea), but not B12 deficiency. * **Pioglitazone (D):** A Thiazolidinedione (PPAR-γ agonist). Key side effects include fluid retention, weight gain, and increased risk of fractures; it has no impact on B12 absorption. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** Metformin-induced B12 deficiency can be reversed by **Calcium supplementation** or oral Vitamin B12. * **Drug of Choice:** Metformin is the DOC for T2DM, especially in obese patients, as it is "weight neutral" or promotes slight weight loss. * **Contraindication:** The most serious (though rare) side effect is **Lactic Acidosis**. It should be avoided if eGFR <30 mL/min. * **Mechanism:** Metformin primarily acts by activating **AMP-activated protein kinase (AMPK)**, leading to decreased hepatic gluconeogenesis.

Practice by Chapter

Hypothalamic and Pituitary Hormones

Practice Questions

Thyroid Drugs and Antithyroid Agents

Practice Questions

Insulin and Oral Hypoglycemic Agents

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Adrenocorticosteroids

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Sex Hormones: Estrogens and Progestins

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Androgens and Anabolic Steroids

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Hormonal Contraceptives

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Drugs Affecting Calcium Metabolism

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Drugs for Osteoporosis

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Pharmacological Management of Obesity

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