Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 391: All of the following are true about GLP-1 analogues EXCEPT?

A. All drugs have to be given subcutaneously
B. Exenatide is safe in renal failure (Correct Answer)
C. They can lead to acute pancreatitis
D. Liraglutide can lead to retinopathy

Explanation: **Explanation:** The correct answer is **B**, as Exenatide is **not** safe in renal failure. **1. Why Option B is the Correct Answer (The False Statement):** Exenatide is primarily eliminated by the kidneys via glomerular filtration. Its clearance is significantly reduced in patients with renal impairment. It is strictly **contraindicated** in patients with severe renal impairment or end-stage renal disease (CrCl <30 mL/min) due to the risk of accumulation and nephrotoxicity. In contrast, Liraglutide is generally considered safer in mild-to-moderate renal impairment as it is not primarily cleared by the kidneys. **2. Analysis of Other Options:** * **Option A (Subcutaneous administration):** Most GLP-1 analogues (Exenatide, Liraglutide, Dulaglutide) are administered subcutaneously. While an oral formulation of Semaglutide exists (Rybelsus), the traditional class characteristic taught for exams is their peptide nature, requiring parenteral delivery to avoid gastric degradation. * **Option C (Acute Pancreatitis):** This is a well-documented, high-yield adverse effect of GLP-1 agonists and DPP-4 inhibitors. Patients presenting with severe abdominal pain radiating to the back should have these drugs discontinued immediately. * **Option D (Retinopathy):** Large clinical trials (like SUSTAIN-6) have shown that rapid improvement in glycemic control with potent GLP-1 agonists like Semaglutide and Liraglutide can lead to a transient worsening of diabetic retinopathy. **Clinical Pearls for NEET-PG:** * **Weight Loss:** GLP-1 analogues are highly effective for weight loss (Liraglutide and Semaglutide are FDA-approved for obesity). * **CV Benefit:** Liraglutide, Dulaglutide, and Semaglutide reduce the risk of Major Adverse Cardiovascular Events (MACE). * **Contraindication:** Avoid in patients with a personal or family history of **Medullary Thyroid Carcinoma (MTC)** or Multiple Endocrine Neoplasia type 2 (MEN 2).

Question 392: All of the following agents may be used in the management of Chronic Hypocalcemia, except:

A. Etidronate (Correct Answer)
B. Thiazides
C. Elemental calcium
D. Vitamin D analogs

Explanation: **Explanation:** The goal of managing **Chronic Hypocalcemia** is to increase serum calcium levels and prevent long-term complications like osteomalacia or tetany. **Why Etidronate is the Correct Answer:** **Etidronate** is a first-generation **Bisphosphonate**. Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption. By preventing the release of calcium from the bone into the bloodstream, they **lower serum calcium levels**. Therefore, Etidronate is used to treat *hypercalcemia* (e.g., malignancy-associated) and Paget’s disease, making it contraindicated and inappropriate for the management of hypocalcemia. **Analysis of Incorrect Options:** * **Elemental Calcium (Option C):** This is the mainstay of treatment. Oral calcium carbonate or calcium citrate is used to directly supplement and maintain serum calcium levels. * **Vitamin D Analogs (Option D):** Agents like Calcitriol or Alfacalcidol are essential as they increase the intestinal absorption of calcium and phosphate. * **Thiazides (Option B):** Unlike loop diuretics (which are "calciuric"), Thiazide diuretics **increase renal calcium reabsorption** in the distal convoluted tubule. They are often used as an adjunct in hypocalcemia to reduce hypercalciuria and prevent the formation of calcium stones. **NEET-PG High-Yield Pearls:** * **Acute Hypocalcemia:** Treated with IV Calcium Gluconate (preferred over Calcium Chloride due to less tissue irritation). * **Bisphosphonates:** Can cause "Hungry Bone Syndrome" or transient hypocalcemia after the first dose. * **Teriparatide (PTH analog):** Though it increases calcium, it is primarily used for osteoporosis, not as a first-line agent for chronic hypocalcemia unless it is due to hypoparathyroidism.

Question 393: The lymphocytopenia seen a few hours after administration of a large dose of prednisone to a patient with lymphocytic leukemia is due to?

A. massive lymphocytic apoptosis (Correct Answer)
B. bone marrow depression
C. activation of cytotoxic cells
D. stimulation of natural killer cell activity

Explanation: **Explanation** The correct answer is **A. massive lymphocytic apoptosis.** **Mechanism of Action:** Glucocorticoids like prednisone exert potent lymphotoxic effects. When administered in pharmacological doses, they bind to intracellular glucocorticoid receptors, leading to the modulation of gene transcription. In lymphoid cells (specifically T-cells and neoplastic B-cells), this triggers a cascade of endonucleases that cause DNA fragmentation, resulting in **programmed cell death (apoptosis)**. This effect is rapid, occurring within a few hours, and is the primary reason steroids are used in the induction protocols for acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL). **Why other options are incorrect:** * **B. Bone marrow depression:** While steroids can suppress certain cell lines over long-term use, the acute drop in peripheral lymphocytes seen within hours is due to the destruction and redistribution of existing cells, not a failure of production in the marrow. * **C & D. Activation of cytotoxic/NK cells:** Glucocorticoids are actually **immunosuppressive**. They inhibit the function of cytotoxic T-lymphocytes and natural killer (NK) cells by suppressing cytokine production (like IL-2). They do not activate these cells to kill leukemic cells. **High-Yield NEET-PG Pearls:** * **Redistribution vs. Destruction:** Steroids cause lymphocytopenia, monocytopenia, and eosinopenia (due to redistribution to lymphoid tissue and apoptosis). Conversely, they cause **neutrophilia** (by decreasing the margination of neutrophils). * **Steroid-induced Psychosis:** A common side effect of high-dose prednisone that frequently appears in exams. * **Drug of Choice:** Dexamethasone is often preferred over prednisone for CNS involvement in leukemia due to its superior CNS penetration.

Question 394: Which of the following drugs acts by stimulating osteoblasts?

A. Teriparatide (Correct Answer)
B. Raloxifene
C. Risedronate
D. Denosumab

Explanation: ### Explanation The correct answer is **Teriparatide**. **1. Why Teriparatide is correct:** Teriparatide is a recombinant form of human **Parathyroid Hormone (PTH 1-34)**. While continuous high levels of PTH (as seen in hyperparathyroidism) cause bone resorption, **intermittent (pulsatile) administration** of Teriparatide has a paradoxical **anabolic effect**. It directly stimulates **osteoblasts** to form new bone, increases bone mineral density, and improves bone architecture. It is currently the only class of drugs (along with Abaloparatide) that primarily builds bone rather than just preventing its breakdown. **2. Why the other options are incorrect:** * **Raloxifene:** A Selective Estrogen Receptor Modulator (SERM). It acts as an estrogen agonist in bone, inhibiting **osteoclast** activity. It does not stimulate osteoblasts. * **Risedronate:** A Bisphosphonate. These drugs bind to hydroxyapatite crystals and are taken up by **osteoclasts**, inducing their apoptosis and inhibiting bone resorption. * **Denosumab:** A monoclonal antibody against **RANKL** (Receptor Activator of Nuclear Factor kappa-B Ligand). By inhibiting RANKL, it prevents the maturation and activation of **osteoclasts**. **3. NEET-PG High-Yield Pearls:** * **Mechanism:** Teriparatide increases the number and function of osteoblasts by activating the PTH1 receptor (a G-protein coupled receptor). * **Clinical Use:** Severe osteoporosis or patients who fail bisphosphonate therapy. * **Black Box Warning:** Risk of **Osteosarcoma** (observed in rat studies); hence, treatment is generally limited to a maximum of 2 years. * **Contraindications:** Paget’s disease of bone, prior radiation to the skeleton, or unexplained elevation of alkaline phosphatase.

Question 395: Which of the following statements regarding bromocriptine is true?

A. It acts as an agonist to dopamine receptors. (Correct Answer)
B. It can be used in active peptic ulceration.
C. It does not cause postural hypotension.
D. It has possible neuroprotective effects.

Explanation: **Bromocriptine** is a semi-synthetic ergot alkaloid that acts as a potent **D2 receptor agonist** and a partial D1 antagonist [3, 2]. 1. **Why Option A is Correct:** Bromocriptine directly stimulates dopamine receptors in the tuberoinfundibular pathway (inhibiting prolactin release from the anterior pituitary) and the nigrostriatal pathway (improving motor control) [2]. This makes it a primary treatment for hyperprolactinemia, prolactinomas, and Parkinson’s disease [1, 2]. 2. **Why Other Options are Incorrect:** * **Option B:** Bromocriptine is **contraindicated** in patients with active peptic ulceration because it can increase the risk of gastrointestinal bleeding. * **Option C:** Postural (orthostatic) hypotension is a **common side effect** of bromocriptine, especially during the initiation of therapy (the "first-dose phenomenon"). Patients are often advised to take the first dose at bedtime. * **Option D:** Unlike newer non-ergot agonists like **Pramipexole** or **Ropinirole**, bromocriptine does not have proven neuroprotective effects. **High-Yield NEET-PG Pearls:** * **Drug of Choice (DOC):** While bromocriptine was traditionally used, **Cabergoline** is now the DOC for prolactinomas due to its higher efficacy, longer half-life (twice-weekly dosing), and better side-effect profile [1]. * **Specific Use:** Bromocriptine is specifically preferred over cabergoline when **pregnancy** is desired, as it has a longer track record of safety data in pregnancy. * **Other Indications:** It is also FDA-approved for the treatment of **Type 2 Diabetes Mellitus** (Quickrelease formulation) and Acromegaly [1]. * **Key Side Effects:** Nausea/vomiting (due to CTZ stimulation), digital vasospasm, and erythromelalgia [2].

Question 396: Which bisphosphonate is approved for the treatment of osteoporosis and is administered on a yearly basis?

A. Alendronate
B. Zoledronate (Correct Answer)
C. Risedronate
D. Ibandronate

Explanation: **Explanation:** **Zoledronate (Zoledronic acid)** is the correct answer because it is the most potent bisphosphonate available. Due to its high affinity for mineralized bone and slow release from the bone matrix, it has a very long duration of action. For the treatment of postmenopausal osteoporosis, it is administered as a **5 mg intravenous infusion once yearly**. **Analysis of Incorrect Options:** * **Alendronate:** A first-line oral bisphosphonate typically administered **once weekly** (70 mg) or daily (10 mg). It must be taken on an empty stomach with a full glass of water to avoid esophageal irritation. * **Risedronate:** Another oral bisphosphonate administered either **daily, weekly, or monthly**. * **Ibandronate:** This can be administered **monthly (oral)** or **every three months (intravenous)**. It is not approved for yearly administration. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Bisphosphonates are pyrophosphate analogs that inhibit **osteoclast-mediated bone resorption** by inducing osteoclast apoptosis and inhibiting the mevalonate pathway (specifically the enzyme farnesyl pyrophosphate synthase). * **Adverse Effects:** * **Oral:** Erosive esophagitis (patients must remain upright for 30 minutes). * **IV (Zoledronate):** Acute phase reaction (flu-like symptoms) and potential nephrotoxicity. * **Class-wide:** Osteonecrosis of the jaw (ONJ) and atypical subtrochanteric fractures. * **Contraindication:** Avoid in patients with severe renal impairment (Creatinine Clearance <35 mL/min).

Question 397: Bromocriptine is an agonist of which neurotransmitter receptor?

A. Dopamine (Correct Answer)
B. Serotonin
C. Acetylcholine
D. Epinephrine

Explanation: **Explanation:** **Bromocriptine** is a semi-synthetic ergot alkaloid that acts as a potent **D2 receptor agonist** and a partial D1 antagonist. In the pituitary gland, dopamine acts as the primary Prolactin-Inhibiting Hormone (PIH). By stimulating D2 receptors on lactotrophs in the anterior pituitary, Bromocriptine inhibits the synthesis and release of prolactin. **Analysis of Options:** * **A. Dopamine (Correct):** Bromocriptine mimics the action of endogenous dopamine. It is primarily used to treat hyperprolactinemia, prolactinomas, and acromegaly. It is also used in Parkinson’s disease to provide direct stimulation of striatal dopamine receptors. * **B. Serotonin:** While some ergot derivatives (like LSD or Ergotamine) interact with 5-HT receptors, Bromocriptine’s primary therapeutic mechanism is via dopaminergic pathways. * **C. Acetylcholine:** Bromocriptine does not have significant activity at nicotinic or muscarinic receptors. * **D. Epinephrine:** Bromocriptine does not act as an agonist at adrenergic receptors; in fact, some ergot derivatives exhibit alpha-adrenergic blocking properties, but this is not its primary mechanism. **High-Yield Clinical Pearls for NEET-PG:** 1. **Drug of Choice (DOC):** While Bromocriptine was traditionally the DOC for **Prolactinoma**, **Cabergoline** is now preferred due to its higher efficacy, longer half-life (twice-weekly dosing), and better side-effect profile. 2. **Other Uses:** It is used in **Type 2 Diabetes Mellitus** (Quick-release formulation) to improve glycemic control by modulating hypothalamic circadian rhythms. 3. **Side Effects:** Common side effects include nausea, dizziness, and orthostatic hypotension. Long-term ergot use is associated with **retroperitoneal/pleuropulmonary fibrosis** and cardiac valvulopathy. 4. **Specific Indication:** It is used to suppress physiological lactation (though no longer routinely recommended for this due to stroke risks).

Question 398: True about lispro-insulin is:

A. Action is faster and short in duration than regular insulin.
B. It is given 15 minutes prior to a meal.
C. Source is lamb.
D. Action is faster and of longer duration than regular insulin. (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Action is faster and of longer duration than regular insulin.** **Understanding the Concept:** Insulin Lispro is a **rapid-acting insulin analogue** created by reversing the amino acids at positions B28 (Proline) and B29 (Lysine). This modification prevents the formation of hexamers, allowing the insulin to remain as monomers that are absorbed rapidly into the bloodstream. While it has a faster onset of action (5–15 minutes) compared to regular insulin, its metabolic effect and duration of action are slightly more sustained/effective in controlling postprandial glucose spikes, making it a preferred choice for mealtime coverage. **Analysis of Options:** * **Option A & B:** While Lispro is indeed faster, it is typically administered **immediately (0–5 minutes) before or even after a meal**, rather than 15–30 minutes prior (which is the requirement for Regular Insulin). Its duration is shorter than NPH but clinically provides a more physiological profile for mealtime spikes. * **Option C:** Modern insulins, including Lispro, are produced using **Recombinant DNA technology** (E. coli or Yeast). Animal sources like beef or pork are obsolete in modern practice due to immunogenicity; lamb was never a standard source. **High-Yield Clinical Pearls for NEET-PG:** * **Rapid-Acting Analogues:** Remember the mnemonic **"No LAG"** (**L**ispro, **A**spart, **G**lulisine). * **Onset:** 5–15 minutes (Fastest). * **Peak:** 1–2 hours. * **Duration:** 3–5 hours. * **Advantage:** Lower risk of postprandial hyperglycemia and late-phase hypoglycemia compared to regular insulin. * **Route:** Can be used in subcutaneous pumps; however, for DKA (IV use), Regular Insulin remains the gold standard.

Question 399: Which regimen of corticosteroids has the maximum potential for adverse effects?

A. Prednisolone 60 mg/day orally for 7 days
B. Dexamethasone 4 mg intravenous daily for 3 days
C. Methylprednisolone 1000 mg intravenous twice single dose
D. Prednisolone 20 mg/day orally for one year (Correct Answer)

Explanation: **Explanation** The adverse effects of corticosteroids are determined by two primary factors: the **potency/dose** and, more significantly, the **duration of therapy**. **Why Option D is Correct:** The potential for serious systemic side effects—such as **Hypothalamic-Pituitary-Adrenal (HPA) axis suppression**, iatrogenic Cushing’s syndrome, osteoporosis, cataracts, and opportunistic infections—is directly proportional to the **chronicity of use**. While 20 mg of Prednisolone is a moderate dose, administering it daily for **one year** ensures prolonged exposure, leading to cumulative toxicity and permanent physiological changes. Any course exceeding 2-3 weeks carries a significantly higher risk than high-dose short bursts. **Analysis of Incorrect Options:** * **Options A & B:** These represent short-term "burst" therapies (7 days and 3 days, respectively). Short courses (less than 2 weeks), even at relatively high doses, rarely cause HPA axis suppression or permanent metabolic side effects. * **Option C:** This is "Pulse Therapy." While 1000 mg is a massive dose, a single or limited pulse (usually 3 days) is generally better tolerated in terms of long-term systemic toxicity compared to chronic daily administration, as the body has time to recover after the pulse. **Clinical Pearls for NEET-PG:** * **HPA Suppression:** Occurs if steroids are used for >2 weeks. Tapering is mandatory in such cases to avoid adrenal crisis. * **Mineralocorticoid Potency:** Fludrocortisone > Aldosterone > Hydrocortisone. (Prednisolone and Dexamethasone have minimal to no salt-retaining activity). * **Anti-inflammatory Potency:** Dexamethasone (30) > Methylprednisolone (5) > Prednisolone (4) > Hydrocortisone (1). * **Most common side effect of inhaled steroids:** Oropharyngeal candidiasis (prevented by using a spacer or rinsing the mouth).

Question 400: Tamoxifen is:

A. Non-steroidal antiprogesterone
B. Non-steroidal antioestrogenic (Correct Answer)
C. Synthetic progestogen norethindrone
D. Competitive inhibitor of 5-alpha reductase

Explanation: **Explanation:** **Tamoxifen** is a **Selective Estrogen Receptor Modulator (SERM)**. It is a non-steroidal compound that exhibits a "mixed" profile: it acts as a competitive antagonist at estrogen receptors in the breast but as a partial agonist in other tissues like the bone and endometrium. 1. **Why Option B is Correct:** Tamoxifen is chemically **non-steroidal** (triphenylethylene derivative). Its primary clinical utility stems from its **antioestrogenic** effect on mammary tissue, where it blocks the binding of estrogen to its receptor, thereby inhibiting the growth of estrogen-dependent breast cancer cells. 2. **Why Other Options are Incorrect:** * **Option A:** Mifepristone (RU-486) is the classic example of a non-steroidal antiprogesterone. * **Option C:** Norethindrone is a 19-nortestosterone derivative used as a synthetic progestogen in oral contraceptives. * **Option D:** Finasteride and Dutasteride are competitive inhibitors of 5-alpha reductase, used in BPH and male pattern baldness. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Tamoxifen is the gold standard for adjuvant treatment of **ER-positive breast cancer** in both pre- and post-menopausal women. * **Agonist Effects (Side Effects):** Because it is an agonist in the uterus, it increases the risk of **Endometrial Carcinoma**. It also has a pro-coagulant effect, increasing the risk of **Deep Vein Thrombosis (DVT)** and pulmonary embolism. * **Beneficial Agonist Effect:** It prevents bone loss (decreases osteoporosis) in post-menopausal women. * **Metabolism:** It is a prodrug converted to its active metabolite, **Endoxifen**, by the enzyme **CYP2D6**.

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

Practice Questions

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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