Endocrine Pharmacology Practice Questions

Q: Which of the following immunosuppressive agents has a side effect of osteoporosis?

Glucocorticoids. **Explanation:** **Glucocorticoids** (Option C) are the primary cause of drug-induced osteoporosis. They induce bone loss through a multi-factorial mechanism: 1. **Direct Inhibition:** They inhibit osteoblast (bone-forming cells) activity and increase osteoclast (bone-resorbing cells) lifespan. 2. **Calcium Homeostasis:** They decrease intestinal calcium absorption and increase renal calcium excretion. 3. **Hormonal Impact:** They suppress the gonadotropin-releasing hormone, leading to lower levels of estrogen and testosterone, which are essential for maintaining bone density. **Analysis of Incorrect Options:** * **Cyclophosphamide (Option A):** An alkylating agent primarily known for **hemorrhagic cystitis** (prevented by Mesna) and gonadotoxicity. While it can cause premature menopause (leading to secondary bone loss), it is not directly osteoporotic like steroids. * **Methotrexate (Option B):** An antimetabolite (DHFR inhibitor). Its hallmark toxicities include **myelosuppression**, hepatotoxicity, and pulmonary fibrosis. "Methotrexate osteopathy" is rare and typically only seen with high-dose chemotherapy, not standard immunosuppressive doses. * **Mycophenolate Mofetil (Option D):** An IMPDH inhibitor used in transplants. Its main side effects are **gastrointestinal distress** (diarrhea) and bone marrow suppression. It does not affect bone mineral density. **NEET-PG High-Yield Pearls:** * **Glucocorticoid-Induced Osteoporosis (GIOP):** It is the most common cause of secondary osteoporosis. Bone loss is most rapid in the first 6 months of therapy. * **Prophylaxis:** Patients on long-term steroids (>3 months) should be started on **Bisphosphonates** (e.g., Alendronate) along with Calcium and Vitamin D supplements. * **Other Steroid Side Effects:** Cushingoid features, hyperglycemia, cataracts, avascular necrosis of the femoral head, and psychosis.

Q: All of the following are natural estrogens EXCEPT:

Ethinylestradiol. **Explanation:** The distinction between natural and synthetic estrogens is a high-yield concept in endocrine pharmacology. **1. Why Ethinylestradiol is the correct answer:** Ethinylestradiol is a **synthetic derivative** of estradiol. It is created by adding an ethinyl group at the C17 position of the steroid nucleus. This structural modification makes the molecule resistant to first-pass metabolism in the liver, significantly increasing its oral bioavailability and potency compared to natural estrogens. This is why it is the most common estrogenic component used in Combined Oral Contraceptive Pills (COCPs). **2. Why the other options are incorrect:** The body naturally produces three major estrogens, often referred to as E1, E2, and E3: * **Estradiol (E2):** The most potent and primary estrogen produced by the ovaries in premenopausal women. * **Estrone (E1):** A weaker estrogen; it is the primary circulating estrogen after menopause, largely derived from the peripheral conversion of androstenedione in adipose tissue. * **Estriol (E3):** The least potent natural estrogen; it is produced in large quantities by the placenta during pregnancy and serves as a marker of fetal well-being. **Clinical Pearls for NEET-PG:** * **Potency Order:** Estradiol (E2) > Estrone (E1) > Estriol (E3). * **Mestranol:** Another synthetic estrogen (a prodrug converted to ethinylestradiol). * **Diethylstilbestrol (DES):** A non-steroidal synthetic estrogen historically linked to clear cell adenocarcinoma of the vagina in daughters of treated women. * **Metabolism:** Natural estrogens have low oral bioavailability due to rapid hepatic metabolism, whereas synthetic estrogens like ethinylestradiol are orally active.

Q: Octreotide is not indicated in which of the following conditions?

Glucagonoma syndrome. **Explanation:** The correct answer is **D. Glucagonoma syndrome**. While Octreotide is a synthetic analog of somatostatin used to manage various neuroendocrine tumors, it is **not** the primary treatment for Glucagonoma syndrome in the context of this question's typical NEET-PG framing. In Glucagonoma, while Octreotide can reduce glucagon levels, it often fails to resolve the characteristic skin rash (**Necrolytic Migratory Erythema**) and can paradoxically worsen glucose intolerance by inhibiting insulin secretion. **Analysis of Options:** * **A. Variceal Bleeding:** Octreotide is a first-line treatment. It causes splanchnic vasoconstriction (by inhibiting glucagon, a vasodilator), thereby reducing portal venous pressure and controlling bleeding. * **B. Refractory Diarrhea in AIDS:** Octreotide is indicated for severe secretory diarrhea associated with AIDS or chemotherapy when standard antidiarrheals fail. It slows intestinal motility and reduces fluid secretion. * **C. Carcinoid Syndrome:** This is a classic indication. Octreotide effectively controls the flushing and severe diarrhea by inhibiting the release of serotonin and other vasoactive peptides. **NEET-PG High-Yield Pearls:** * **Mechanism:** Octreotide is a long-acting somatostatin analog (potent inhibitor of GH, glucagon, insulin, and gastrin). * **Side Effects:** The most common side effects are **steatorrhea** (due to inhibition of pancreatic enzymes) and **biliary sludge/gallstones** (due to inhibition of cholecystokinin and gallbladder contractility). * **Other Indications:** Acromegaly, VIPoma (Verner-Morrison syndrome), and Zollinger-Ellison syndrome. * **Clinical Note:** For Glucagonoma, the definitive treatment is surgical resection; Octreotide is only supportive.

Q: Progestogens are used for all of the following conditions except:

Inhibition of lactation. **Explanation:** Progestogens are synthetic derivatives of progesterone used primarily to regulate the menstrual cycle, protect the endometrium, and maintain pregnancy. **Why "Inhibition of Lactation" is the correct answer:** Lactation is primarily inhibited by **Dopamine agonists** (e.g., **Cabergoline**, Bromocriptine) which suppress prolactin release from the anterior pituitary. While high doses of Estrogen were historically used to suppress lactation, Progestogens do not have a significant inhibitory effect on milk production. In fact, Progestogen-only pills (POPs) are the preferred hormonal contraceptive during breastfeeding because they do not interfere with the quantity or quality of breast milk, unlike combined pills. **Analysis of other options:** * **Anovulatory cycles:** Progestogens are used to induce "withdrawal bleeding" and regulate cycles in patients with PCOS or other causes of anovulation. * **Pubertal menorrhagia:** Heavy menstrual bleeding in adolescents is often due to an immature hypothalamic-pituitary-ovarian axis leading to anovulation. Progestogens help stabilize the estrogen-primed endometrium and control bleeding. * **Endometrial carcinoma:** High-dose progestogens (e.g., Medroxyprogesterone acetate) are used as palliative therapy in advanced or recurrent endometrial cancer because they antagonize the proliferative effects of estrogen on the endometrium. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice for lactation suppression:** Cabergoline (more effective and fewer side effects than Bromocriptine). * **Lactational Amenorrhea Method (LAM):** Effective only if the mother is exclusively breastfeeding and remains amenorrheic (usually up to 6 months). * **Progestogen of choice for Endometriosis:** Dienogest. * **Progestogen used in HRT to prevent endometrial hyperplasia:** Micronized progesterone or Medroxyprogesterone.

Q: Hypercalcemia is decreased by all of the following EXCEPT:

Lithium. **Explanation:** The correct answer is **Lithium** because it is a known cause of **hypercalcemia**, rather than a treatment for it. Lithium shifts the set-point of the calcium-sensing receptor (CaSR) in the parathyroid gland, requiring higher serum calcium levels to suppress Parathyroid Hormone (PTH) release. Additionally, it reduces renal calcium excretion. This combination often leads to lithium-induced hyperparathyroidism. **Analysis of Options:** * **Etidronate (Option A):** This is a first-generation bisphosphonate. Bisphosphonates inhibit osteoclast-mediated bone resorption, effectively lowering serum calcium levels. They are a mainstay in treating hypercalcemia of malignancy. * **Calcitonin (Option B):** Produced by the parafollicular C-cells of the thyroid, calcitonin directly inhibits osteoclasts and increases renal calcium excretion. It is used for the rapid (though short-term) reduction of calcium in emergency settings. * **Glucocorticoids (Option D):** Steroids (like Prednisone) decrease intestinal calcium absorption and inhibit cytokine-mediated bone resorption. They are particularly effective in hypercalcemia caused by sarcoidosis, Vitamin D toxicity, or certain lymphomas. **NEET-PG High-Yield Pearls:** * **Lithium Side Effects:** Remember the mnemonic **LITH:** **L**eukocytosis, **I**nsipidus (Nephrogenic Diabetes Insipidus), **T**remors/Teratogenicity (Ebstein's Anomaly), **H**yperparathyroidism/Hypothyroidism. * **Drug of Choice:** For acute severe hypercalcemia, the initial management is vigorous **intravenous hydration with normal saline**, followed by loop diuretics (Furosemide) once hydrated. * **Bisphosphonates:** Zoledronic acid is the most potent bisphosphonate used for hypercalcemia of malignancy.

Q: Which vitamin D preparation would be the most appropriate in a patient with poor renal function?

Calcitriol. ### Explanation The correct answer is **Calcitriol (Option B)**. **Underlying Medical Concept:** Vitamin D undergoes a two-step activation process in the body to become biologically active: 1. **First Hydroxylation:** Occurs in the **liver** via the enzyme 25-hydroxylase to form 25-hydroxyvitamin D (Calcifediol). 2. **Second Hydroxylation:** Occurs in the **kidneys** via the enzyme **1-alpha-hydroxylase** to form 1,25-dihydroxyvitamin D (**Calcitriol**). In patients with **poor renal function** (Chronic Kidney Disease), the kidneys cannot perform this second hydroxylation step. Therefore, these patients cannot convert precursor forms of Vitamin D into the active hormone. **Calcitriol**, being the pre-activated form (1,25-(OH)₂D₃), bypasses the need for renal activation and is the treatment of choice. **Analysis of Incorrect Options:** * **Cholecalciferol (A) & Ergocalciferol (C):** These are Vitamin D3 and D2, respectively. They are inactive precursors that require both hepatic and renal hydroxylation. In renal failure, they remain inactive. * **Calcifediol (D):** This is 25-hydroxyvitamin D. While it bypasses the liver, it still requires the renal 1-alpha-hydroxylase enzyme to become active. **NEET-PG High-Yield Pearls:** * **Alfacalcidol:** A synthetic analogue (1-alpha-OH-D3) that requires only hepatic hydroxylation. It is also useful in renal failure because it bypasses the kidney. * **Drug of choice for Vitamin D deficiency in Liver Cirrhosis:** Calcifediol (bypasses the liver). * **Drug of choice for Vitamin D deficiency in Renal Failure:** Calcitriol or Alfacalcidol. * **Paricalcitol:** A calcitriol analogue used specifically to reduce Parathyroid Hormone (PTH) levels in secondary hyperparathyroidism of CKD with less risk of hypercalcemia.

Q: Calcitonin is not indicated in which of the following conditions?

Thyrotoxicosis. **Explanation:** Calcitonin is a hormone secreted by the parafollicular (C-cells) of the thyroid gland. Its primary physiological role is to lower serum calcium levels by inhibiting osteoclast-mediated bone resorption and increasing renal calcium excretion. **Why Thyrotoxicosis is the Correct Answer:** Thyrotoxicosis (excess thyroid hormone) is not an indication for calcitonin. While severe hyperthyroidism can occasionally cause mild hypercalcemia due to increased bone turnover, the treatment focuses on anti-thyroid drugs (e.g., Carbimazole), beta-blockers, and radioactive iodine. Calcitonin has no role in managing the underlying pathophysiology of thyrotoxicosis. **Analysis of Other Options:** * **Paget’s Disease:** Calcitonin is a second-line treatment (after bisphosphonates). It effectively reduces bone pain and suppresses high bone turnover by inhibiting overactive osteoclasts. * **Hyperparathyroidism & Hypervitaminosis D:** Both conditions result in significant **hypercalcemia**. Calcitonin is indicated for the emergency management of hypercalcemic crises because it provides a rapid (though short-lived) reduction in serum calcium levels. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Acts via GPCRs to inhibit osteoclasts. * **Tachyphylaxis:** A key limitation of calcitonin is the rapid development of tolerance (tachyphylaxis) due to the downregulation of receptors, making it unsuitable for long-term hypercalcemia management. * **Salmon Calcitonin:** Used clinically because it is more potent and has a longer half-life than human calcitonin. * **Route:** Administered parenterally or via nasal spray (common for postmenopausal osteoporosis). * **Tumor Marker:** Serum calcitonin levels are used to monitor **Medullary Carcinoma of the Thyroid**.

Q: Which is the fastest-acting antithyroid medication?

Potassium iodide. **Explanation:** The correct answer is **Potassium Iodide (A)**. **Why it is the fastest-acting:** Potassium iodide (and other iodides like Lugol’s iodine) works via the **Wolff-Chaikoff effect**, where high concentrations of iodine acutely inhibit the organification of iodine and the synthesis of thyroid hormones. More importantly, iodides uniquely **inhibit the release of pre-formed thyroid hormones** from the colloid into the circulation. This effect is rapid, occurring within 24–48 hours, making it the fastest-acting agent to lower serum T3/T4 levels. **Why the other options are incorrect:** * **Propylthiouracil (PTU), Carbimazole, and Methimazole (B, C, D):** These are thioamides. They work by inhibiting the enzyme **thyroid peroxidase (TPO)**, which prevents the synthesis of *new* thyroid hormones. However, they do not block the release of hormones already stored in the thyroid follicle. Consequently, their clinical effect is delayed (usually 1–3 weeks) until the pre-formed hormone stores are depleted. **High-Yield Clinical Pearls for NEET-PG:** * **Thyroid Storm:** Potassium iodide is used in thyroid storm due to its rapid action, but it must be administered **1 hour after** the first dose of thioamides to prevent the "Jod-Basedow" effect (where the iodine is used as fuel for more hormone synthesis). * **Pre-operative use:** Iodides are given 10 days before thyroidectomy because they decrease the **size and vascularity** of the thyroid gland, making surgery safer. * **Escape Phenomenon:** The effect of iodides is transient; the thyroid "escapes" from the Wolff-Chaikoff effect after 10–14 days, leading to a rebound of thyrotoxicosis if used alone. * **PTU vs. Methimazole:** PTU is preferred in the **1st trimester** of pregnancy and thyroid storm (as it also inhibits peripheral conversion of T4 to T3), while Methimazole is the drug of choice for most other cases of hyperthyroidism.

Q: Weight loss is seen with all of the following drug classes except?

DPP-4 inhibitors. **Explanation:**The core concept behind this question is the metabolic impact of various anti-diabetic drug classes on body weight. **DPP-4 Inhibitors (e.g., Sitagliptin, Vildagliptin):** These drugs work by inhibiting the enzyme dipeptidyl peptidase-4, which degrades endogenous GLP-1. While they increase insulin secretion and decrease glucagon, the physiological levels of GLP-1 achieved are not high enough to significantly delay gastric emptying or induce satiety. Therefore, DPP-4 inhibitors are clinically classified as **weight-neutral**.**Why other options are incorrect:** * **GLP-1 Agonists (e.g., Liraglutide, Semaglutide):** These are potent weight-loss agents [2]. They achieve pharmacological levels of GLP-1, which slows gastric emptying and acts on the hypothalamus to increase satiety [1, 4]. * **SGLT-2 Inhibitors (e.g., Dapagliflozin, Empagliflozin):** These induce weight loss primarily through **caloric loss** (glucosuria) and mild osmotic diuresis. * **Pramlintide:** An amylin analogue used in both Type 1 and Type 2 DM. It reduces weight by slowing gastric emptying and suppressing appetite.**High-Yield Clinical Pearls for NEET-PG:** * **Weight Gainers:** Insulin, Sulfonylureas [3], Thiazolidinediones (TZDs), and Meglitinides. * **Weight Losers:** GLP-1 Agonists (Maximum weight loss) [1, 2, 4], SGLT-2 Inhibitors, and Pramlintide. * **Weight Neutral:** Metformin (though often associated with mild loss) and DPP-4 Inhibitors. * **Drug of choice** for obese diabetics: GLP-1 Agonists [1] or SGLT-2 Inhibitors.

Question 1

Which of the following immunosuppressive agents has a side effect of osteoporosis?

Accepted Answer

Glucocorticoids

Answer

Cyclophosphamide

Answer

Methotrexate

Answer

Mycophenolate mofetil

Question 2

All of the following are natural estrogens EXCEPT:

Accepted Answer

Ethinylestradiol

Answer

Estradiol

Answer

Estriol

Answer

Estrone

Question 3

Octreotide is not indicated in which of the following conditions?

Accepted Answer

Glucagonoma syndrome

Answer

Variceal bleeding

Answer

Refractory diarrhea in AIDS

Answer

Carcinoid syndrome

Question 4

Progestogens are used for all of the following conditions except:

Accepted Answer

Inhibition of lactation

Answer

Anovulatory cycles

Answer

Pubertal menorrhagia

Answer

Endometrial carcinoma

Question 5

Ingestion of which of the following drugs during pregnancy increases the risk of vaginal adenocarcinoma in a female offspring?

Accepted Answer

Diethyl stilbestrol

Answer

Chlorpropamide

Answer

Progesterone

Answer

Chloramphenicol

Question 6

Hypercalcemia is decreased by all of the following EXCEPT:

Accepted Answer

Lithium

Answer

Etidronate

Answer

Calcitonin

Answer

Glucocorticoids

Question 7

Which vitamin D preparation would be the most appropriate in a patient with poor renal function?

Accepted Answer

Calcitriol

Answer

Cholecalciferol

Answer

Ergocalciferol

Answer

Calcifediol

Question 8

Calcitonin is not indicated in which of the following conditions?

Accepted Answer

Thyrotoxicosis

Answer

Paget's disease

Answer

Hyperparathyroidism

Answer

Hypervitaminosis D

Question 9

Which is the fastest-acting antithyroid medication?

Accepted Answer

Potassium iodide

Answer

Propylthiouracil

Answer

Carbimazole

Answer

Methimazole

Question 10

Weight loss is seen with all of the following drug classes except?

Accepted Answer

DPP-4 inhibitors

Answer

GLP-1 Agonists

Answer

SGLT-2 Inhibitors

Answer

Pramlintide

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?