Endocrine Pharmacology — MCQs
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Bisphosphonates are prescribed to a patient with which of the following advice?
Which of the following is NOT true for octreotide?
A 52-year-old postmenopausal patient has evidence of low bone mineral density. She and her physician are considering therapy with raloxifene or a combination of conjugated estrogens and medroxyprogesterone acetate. Which of the following patient characteristics is MOST likely to lead them to select raloxifene?
Which of the following corticosteroids has the least mineralocorticoid activity?
What is the safest treatment for hyperthyroidism in pregnant women?
Which corticosteroid has the maximum sodium-retaining potential?
Which of the following drugs may be used to arrest premature labor?
Which of the following is a serious adverse effect seen with zoledronate?
Glibenclamide is preferred over chlorpropamide in the treatment of diabetes mellitus because chlorpropamide is more likely to cause which of the following adverse effects?
What is the drug of choice for neurogenic diabetes insipidus?
Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs
Question 231: Bisphosphonates are prescribed to a patient with which of the following advice?
- A. Take on an empty stomach with plenty of water (Correct Answer)
- B. Take after meals
- C. Discontinue if gastritis develops
- D. Discontinue if severe bone pain occurs
Explanation: **Explanation:** **1. Why Option A is Correct:** Bisphosphonates (e.g., Alendronate, Risedronate) have extremely **poor oral bioavailability** (typically <1%). Their absorption is significantly further impaired by the presence of food, calcium, or iron supplements. Therefore, they must be taken on an **empty stomach** (at least 30 minutes before breakfast) with a full glass of **plain water** to ensure adequate systemic absorption. **2. Why Other Options are Incorrect:** * **Option B:** Taking them after meals would render the drug virtually ineffective due to negligible absorption. * **Option C:** While bisphosphonates can cause esophageal irritation, "gastritis" is not a definitive reason to discontinue the drug immediately [1]. Instead, patients are advised to **remain upright for 30–60 minutes** after ingestion to prevent gastroesophageal reflux and esophagitis. * **Option D:** While "atypical femoral fractures" are a rare long-term complication, transient musculoskeletal pain is a known side effect that usually does not require permanent discontinuation unless severe or indicative of a fracture [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** They inhibit **osteoclast activity** by interfering with the mevalonate pathway (specifically inhibiting farnesyl pyrophosphate synthase) [2]. * **The "Upright Rule":** To prevent the most common side effect—**erosive esophagitis**—patients must not lie down after taking the pill. * **Major Side Effects:** 1. **Osteonecrosis of the Jaw (ONJ):** Especially with IV forms (Zoledronate). 2. **Atypical Subtrochanteric Fractures:** Associated with long-term use (>5 years). * **Drug of Choice:** Bisphosphonates are the first-line treatment for **Postmenopausal Osteoporosis** and **Paget’s disease** [1].
Question 232: Which of the following is NOT true for octreotide?
- A. Used in Acromegaly
- B. Used orally (Correct Answer)
- C. Given in secretory diarrhea
- D. Used in portal hypertension
Explanation: **Explanation:** **Octreotide** is a synthetic long-acting analogue of **Somatostatin** (Growth Hormone Inhibiting Hormone) [1]. 1. **Why Option B is Correct (The False Statement):** Octreotide is a peptide molecule [1]. Like insulin and other peptides, it is susceptible to degradation by gastrointestinal enzymes and has poor mucosal permeability. Therefore, it **cannot be administered orally**. It must be given via **parenteral routes** (Subcutaneous or Intravenous) [3], [5]. 2. **Analysis of Other Options:** * **Option A (Acromegaly):** Octreotide is a first-line medical therapy for acromegaly [3]. It binds to somatostatin receptors (SSTR-2 and SSTR-5) to potently inhibit the secretion of Growth Hormone (GH) and IGF-1 [2], [5]. * **Option C (Secretory Diarrhea):** It is highly effective in controlling secretory diarrhea associated with **Carcinoid syndrome** and **VIPomas** by inhibiting intestinal fluid secretion and slowing GI motility [4]. * **Option D (Portal Hypertension):** In acute variceal bleeding, octreotide is used to reduce portal venous pressure [5]. It causes **splanchnic vasoconstriction** (by inhibiting the release of glucagon and other vasodilatory peptides), thereby reducing blood flow to the portal system [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Half-life:** Octreotide has a much longer half-life (~1.5–2 hours) compared to natural somatostatin (~2–3 minutes) [1], [4]. * **Side Effects:** The most characteristic side effect is the formation of **steatorrhea** and **gallstones (cholelithiasis)** due to the inhibition of cholecystokinin (CCK) release and gallbladder contractility [3], [5]. * **Other Uses:** It is also used in the management of **Zollinger-Ellison Syndrome**, **Insulinomas**, and to reduce output from **pancreatic fistulas**.
Question 233: A 52-year-old postmenopausal patient has evidence of low bone mineral density. She and her physician are considering therapy with raloxifene or a combination of conjugated estrogens and medroxyprogesterone acetate. Which of the following patient characteristics is MOST likely to lead them to select raloxifene?
- A. Previous hysterectomy
- B. Recurrent vaginitis
- C. Strong family history of breast cancer (Correct Answer)
- D. Troublesome hot flushes
Explanation: **Explanation:** The core concept tested here is the pharmacological profile of **Selective Estrogen Receptor Modulators (SERMs)** compared to **Hormone Replacement Therapy (HRT)**. **1. Why Option C is correct:** Raloxifene acts as an **estrogen agonist in bone** (preventing osteoporosis) but as an **estrogen antagonist in breast and uterine tissues**. Because it blocks estrogen receptors in the breast, it significantly reduces the risk of invasive breast cancer. In a patient with a strong family history of breast cancer, raloxifene provides the dual benefit of bone protection and cancer prophylaxis. Conversely, traditional HRT (estrogen + progestin) is associated with a slightly increased risk of breast cancer with long-term use. **2. Why the other options are incorrect:** * **A. Previous hysterectomy:** If a patient has had a hysterectomy, they can take estrogen alone without needing a progestin (like medroxyprogesterone) to protect the endometrium. This usually makes HRT a simpler and often preferred choice over SERMs for symptom control. * **B. Recurrent vaginitis:** Estrogen deficiency causes urogenital atrophy. HRT effectively treats vaginal dryness and atrophy, whereas raloxifene, acting as an antagonist in urogenital tissue, does not improve (and may worsen) these symptoms. * **D. Troublesome hot flushes:** This is a classic "side effect" distinction. While HRT is the gold standard for treating vasomotor symptoms (hot flushes), raloxifene actually **increases** the incidence of hot flushes because of its antagonistic effect in the CNS. **High-Yield NEET-PG Pearls:** * **Raloxifene:** Agonist at Bone; Antagonist at Breast and Endometrium. (Does *not* increase risk of endometrial cancer, unlike Tamoxifen). * **Tamoxifen:** Agonist at Bone and **Endometrium**; Antagonist at Breast. (Increases risk of endometrial hyperplasia/cancer). * **Common Side Effect:** Both SERMs and HRT increase the risk of **Deep Vein Thrombosis (DVT)** and pulmonary embolism. * **Drug of Choice:** For postmenopausal osteoporosis with a high risk of breast cancer = Raloxifene.
Question 234: Which of the following corticosteroids has the least mineralocorticoid activity?
- A. Fludrocortisone
- B. Dexamethasone
- C. Triamcinolone (Correct Answer)
- D. Betamethasone
Explanation: **Explanation:** The potency of corticosteroids is determined by their relative **glucocorticoid** (anti-inflammatory) and **mineralocorticoid** (salt-retaining) activities. **Why Triamcinolone is the correct answer:** Glucocorticoids are classified based on their duration of action and side-effect profile. **Triamcinolone**, along with **Dexamethasone** and **Betamethasone**, is a synthetic steroid designed to maximize anti-inflammatory effects while minimizing mineralocorticoid activity. However, among the options provided, Triamcinolone is traditionally classified as having **zero (negligible)** mineralocorticoid activity. While Dexamethasone and Betamethasone also have minimal salt-retaining effects, Triamcinolone is the classic textbook answer for the "least" or "nil" mineralocorticoid activity in this comparative group. **Analysis of Incorrect Options:** * **Fludrocortisone (A):** This is a potent mineralocorticoid. It has the highest salt-retaining activity among the options and is used clinically for replacement therapy in Addison’s disease. * **Dexamethasone (B) & Betamethasone (D):** These are long-acting, highly potent glucocorticoids. While they have negligible mineralocorticoid activity, they are often ranked slightly behind Triamcinolone in terms of pure "zero" salt retention in comparative pharmacology tables. **High-Yield NEET-PG Pearls:** * **Highest Mineralocorticoid Potency:** Fludrocortisone > Aldosterone > Desoxycorticosterone acetate (DOCA). * **Highest Glucocorticoid Potency:** Betamethasone > Dexamethasone > Triamcinolone > Prednisolone > Hydrocortisone. * **Drug of Choice for Cerebral Edema:** Dexamethasone (due to high potency and low salt retention). * **Fetal Lung Maturity:** Betamethasone or Dexamethasone are used because they cross the placenta and have low protein binding. * **Triamcinolone side effect:** It is specifically associated with muscle wasting (myopathy) more than other steroids.
Question 235: What is the safest treatment for hyperthyroidism in pregnant women?
- A. Radioactive iodine
- B. Methimazole
- C. Carbimazole
- D. Propylthiouracil (Correct Answer)
Explanation: **Explanation:** The management of hyperthyroidism during pregnancy requires a careful balance between maternal health and fetal safety. **Propylthiouracil (PTU)** is the drug of choice during the **first trimester** of pregnancy. **1. Why Propylthiouracil (PTU) is correct:** PTU is highly protein-bound and less lipid-soluble compared to other antithyroid drugs. This results in **minimal placental transfer**, significantly reducing the risk of fetal malformations. It is preferred in the first trimester (the period of organogenesis) to avoid the specific teratogenic effects associated with Methimazole. **2. Why the other options are incorrect:** * **Methimazole & Carbimazole:** These are avoided in the first trimester because they cross the placenta more readily and are associated with **Methimazole Embryopathy**, which includes **Aplasia cutis** (congenital skin defects on the scalp), esophageal atresia, and choanal atresia. However, Methimazole is often preferred in the **second and third trimesters** to avoid PTU-induced maternal hepatotoxicity. * **Radioactive Iodine (I-131):** This is **absolutely contraindicated** in pregnancy. It crosses the placenta and can cause permanent destruction of the fetal thyroid gland, leading to congenital hypothyroidism and cretinism. **3. High-Yield Clinical Pearls for NEET-PG:** * **Switching Rule:** Use PTU in the 1st trimester; switch to Methimazole in the 2nd and 3rd trimesters. * **Mechanism of PTU:** It inhibits thyroid peroxidase (TPO) and, uniquely, inhibits the **peripheral conversion of T4 to T3**. * **Side Effect:** PTU carries a Black Box Warning for **severe fulminant hepatic failure**. * **Breastfeeding:** Both PTU and Methimazole are considered safe during breastfeeding at low doses.
Question 236: Which corticosteroid has the maximum sodium-retaining potential?
- A. Hydrocortisone
- B. Prednisolone
- C. Fludrocortisone (Correct Answer)
- D. Deoxycorticosterone
Explanation: ### Explanation The correct answer is **C. Fludrocortisone**. **Mechanism and Concept:** Corticosteroids are classified based on their relative **glucocorticoid** (anti-inflammatory) and **mineralocorticoid** (sodium-retaining) potencies. Sodium retention is mediated by the activation of mineralocorticoid receptors in the renal distal tubule, leading to sodium reabsorption and potassium excretion. **Fludrocortisone** is a synthetic analog with extremely high mineralocorticoid activity (potency ratio of ~125–250 compared to hydrocortisone), making it the drug of choice for mineralocorticoid replacement therapy. **Analysis of Options:** * **A. Hydrocortisone:** This is the pharmaceutical form of endogenous cortisol. It has equal glucocorticoid and mineralocorticoid potency (1:1 ratio). While it does cause sodium retention, its potential is significantly lower than fludrocortisone. * **B. Prednisolone:** A synthetic glucocorticoid with increased anti-inflammatory action but **reduced** mineralocorticoid activity (0.8 relative to hydrocortisone). It is used primarily for systemic inflammation, not for sodium retention. * **D. Deoxycorticosterone (DOCA):** This is a precursor to aldosterone. While it is a pure mineralocorticoid, its clinical potency and sodium-retaining efficacy are lower than that of fludrocortisone. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Fludrocortisone is the primary treatment for **Addison’s disease** (primary adrenocortical insufficiency) to replace mineralocorticoids. * **Zero Mineralocorticoid Activity:** **Dexamethasone** and **Betamethasone** have negligible sodium-retaining potential, making them ideal when high-dose steroids are needed without causing edema or hypertension. * **Relative Potency Table:** * *Fludrocortisone:* 125–250 (Highest Mineralocorticoid) * *Aldosterone:* 3000 (Endogenous, but not used clinically due to poor oral bioavailability) * *Dexamethasone:* 0 (Highest Glucocorticoid)
Question 237: Which of the following drugs may be used to arrest premature labor?
- A. Diazoxide
- B. Methyldopa
- C. Magnesium sulfate
- D. All of the above (Correct Answer)
Explanation: **Explanation:** The drugs used to arrest premature labor are known as **Tocolytics**. Their primary mechanism is to decrease intracellular calcium or increase cAMP in the myometrium, leading to uterine smooth muscle relaxation. **Why "All of the Above" is correct:** * **Magnesium Sulfate ($MgSO_4$):** It is a traditional tocolytic that acts as a calcium antagonist. It competes with calcium for entry into the cell through voltage-gated channels and inhibits the release of calcium from the sarcoplasmic reticulum. It also provides the added benefit of **fetal neuroprotection** (reducing the risk of cerebral palsy). * **Diazoxide:** This is a potent **K+ channel opener**. By opening ATP-sensitive potassium channels, it causes membrane hyperpolarization, which prevents the opening of voltage-gated calcium channels, thereby relaxing the uterus. While not a first-line agent due to side effects (like hyperglycemia), it possesses significant tocolytic properties. * **Methyldopa:** While primarily known as a centrally acting antihypertensive (the drug of choice for hypertension in pregnancy), it has historically been noted to have mild inhibitory effects on uterine contractions, though it is rarely used for this specific indication today compared to more potent agents. **High-Yield NEET-PG Clinical Pearls:** 1. **First-line Tocolytics:** Currently, **Nifedipine** (Calcium Channel Blocker) and **Atosiban** (Oxytocin Receptor Antagonist) are preferred over $MgSO_4$ due to better safety profiles. 2. **Specific Side Effects:** * **Terbutaline/Ritodrine ($\beta_2$ agonists):** Can cause maternal tachycardia, pulmonary edema, and hyperglycemia. * **Indomethacin (NSAID):** Can cause premature closure of the *ductus arteriosus* and oligohydramnios. 3. **Magnesium Toxicity:** Monitored via the **patellar reflex** (first sign of toxicity to disappear), respiratory rate, and urine output. The antidote is **Calcium Gluconate**.
Question 238: Which of the following is a serious adverse effect seen with zoledronate?
- A. Acute renal failure (Correct Answer)
- B. Ventricular fibrillation
- C. Peptic ulcer
- D. Anterior uveitis
Explanation: **Explanation:** **Zoledronate (Zoledronic acid)** is a high-potency, intravenous nitrogen-containing bisphosphonate used primarily for osteoporosis, Paget’s disease, and bone metastases. **Why Acute Renal Failure is the correct answer:** Zoledronate is excreted unchanged by the kidneys. When administered intravenously, especially if infused too rapidly (less than 15 minutes) or in dehydrated patients, it can cause **acute tubular necrosis (ATN)**. It leads to a transient increase in serum creatinine and, in severe cases, acute renal failure. Therefore, monitoring creatinine clearance and ensuring adequate hydration before administration is mandatory. **Analysis of Incorrect Options:** * **B. Ventricular fibrillation:** While bisphosphonates (especially zoledronate) have been associated with an increased risk of **Atrial Fibrillation** in some trials, they are not typically associated with ventricular fibrillation. * **C. Peptic ulcer:** This is a classic side effect of **oral bisphosphonates** (like Alendronate) due to direct esophageal and gastric mucosal irritation. Since Zoledronate is given IV, it bypasses the GI tract and does not cause peptic ulcers. * **D. Anterior uveitis:** While bisphosphonates can cause ocular inflammation (like scleritis or uveitis), it is considered a rare idiosyncratic reaction rather than a common "serious" adverse effect compared to the systemic impact of renal failure. **High-Yield Clinical Pearls for NEET-PG:** * **Osteonecrosis of the Jaw (ONJ):** A high-yield adverse effect associated with long-term, high-dose IV bisphosphonate therapy, often triggered by invasive dental procedures. * **Acute Phase Reaction:** Patients often experience flu-like symptoms (fever, myalgia) within 24–72 hours of the first IV infusion. * **Contraindication:** Zoledronate is generally contraindicated if Creatinine Clearance (CrCl) is **<35 mL/min**.
Question 239: Glibenclamide is preferred over chlorpropamide in the treatment of diabetes mellitus because chlorpropamide is more likely to cause which of the following adverse effects?
- A. Hypoglycemia
- B. Alcohol intolerance
- C. Cholestatic jaundice
- D. All of the above (Correct Answer)
Explanation: **Explanation:** Glibenclamide (a second-generation sulfonylurea) is generally preferred over Chlorpropamide (a first-generation sulfonylurea) due to the latter’s unfavorable side effect profile and prolonged duration of action. **Why "All of the above" is correct:** Chlorpropamide is notorious for several specific adverse effects that are less common with second-generation agents: 1. **Hypoglycemia:** Chlorpropamide has an exceptionally long half-life (up to 36 hours) and is excreted unchanged by the kidneys. This leads to a high risk of **prolonged, severe hypoglycemia**, especially in elderly patients or those with renal impairment. 2. **Alcohol Intolerance:** Chlorpropamide causes a **Disulfiram-like reaction** (flushing, tachycardia, nausea) when taken with alcohol because it inhibits the enzyme aldehyde dehydrogenase. 3. **Cholestatic Jaundice:** First-generation sulfonylureas, particularly chlorpropamide, are more frequently associated with idiosyncratic liver injury and cholestasis compared to newer agents. **Incorrect Options:** Since all three side effects (A, B, and C) are significantly more prevalent or severe with Chlorpropamide than with Glibenclamide, they collectively justify why Glibenclamide is the safer clinical choice. **High-Yield Clinical Pearls for NEET-PG:** * **SIADH:** Chlorpropamide is the only sulfonylurea that can cause **Dilutional Hyponatremia** by increasing ADH action on renal tubules (SIADH-like effect). * **Safety in Renal Failure:** Glibenclamide is contraindicated in renal failure. **Gliquidone** is the sulfonylurea of choice in patients with renal impairment as it is primarily excreted in bile. * **Mechanism:** Sulfonylureas act by closing **ATP-sensitive K+ channels** in pancreatic beta cells, leading to depolarization and insulin release.
Question 240: What is the drug of choice for neurogenic diabetes insipidus?
- A. Vasopressin
- B. Terlipressin
- C. Desmopressin (Correct Answer)
- D. Pralipressin
Explanation: ### Explanation **Neurogenic (Central) Diabetes Insipidus (DI)** is caused by a deficiency of Antidiuretic Hormone (ADH) from the posterior pituitary. The goal of treatment is to replace this hormone using an analog that mimics its water-retaining effects without causing excessive side effects. **Why Desmopressin is the Correct Answer:** Desmopressin (dDAVP) is a synthetic analog of ADH and is the **drug of choice** for Central DI due to two primary reasons: 1. **Selectivity:** It is a selective **V2 receptor agonist**. By acting on V2 receptors in the renal collecting ducts, it increases water reabsorption. Unlike natural ADH, it has negligible activity at V1 receptors, meaning it does not cause significant vasoconstriction (pressor effects). 2. **Pharmacokinetics:** It has a longer duration of action (8–20 hours) compared to natural vasopressin and can be administered via multiple routes (intranasal, oral, or IV/SC). **Analysis of Incorrect Options:** * **Vasopressin (Option A):** This is the natural hormone. It is non-selective (acts on both V1 and V2) and has a very short half-life (10–20 minutes), making it impractical for long-term management. * **Terlipressin (Option B):** This is a V1-selective analog. It is primarily used for **esophageal varices** and hepatorenal syndrome because it causes potent vasoconstriction. * **Pralipressin (Option D):** This is another vasopressin analog but is not the standard of care for DI; it lacks the favorable V2-selectivity and safety profile of Desmopressin. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Choice:** Intranasal is common, but the **oral** route is increasingly preferred for patient convenience. * **Other Uses of Desmopressin:** Nocturnal enuresis, Von Willebrand Disease (Type 1), and Hemophilia A (it increases Factor VIII and vWF levels). * **Side Effect:** The most serious side effect of Desmopressin is **hyponatremia** (due to water intoxication). * **Nephrogenic DI:** Desmopressin will *not* work here. The drug of choice for Nephrogenic DI is **Thiazide diuretics** (e.g., Hydrochlorothiazide) or Amiloride (if lithium-induced).
Practice by Chapter
Hypothalamic and Pituitary Hormones
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Thyroid Drugs and Antithyroid Agents
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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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