Endocrine Pharmacology Practice Questions

Q: A 75-year-old woman with diabetes is taking oral antidiabetic drugs. She goes without eating for 18 hours, and her serum glucose concentration is 48 mg/dL (hypoglycemic) upon arrival at the emergency department, where she is deemed to be in critical condition. Which of the following drugs most likely aggravated this fasting hypoglycemia?

Glyburide. **Explanation:** The patient is presenting with severe fasting hypoglycemia, a classic side effect of **Sulfonylureas**. **1. Why Glyburide is Correct:** Glyburide is a second-generation sulfonylurea. Its mechanism of action involves binding to the **SUR1 subunit** of the ATP-sensitive $K^+$ channels in pancreatic beta cells. This leads to channel closure, cell depolarization, calcium influx, and the **insulin secretion regardless of blood glucose levels**. Because sulfonylureas act as "insulin secretagogues," they can cause profound and prolonged hypoglycemia, especially in elderly patients or those who skip meals (fasting). Glyburide, in particular, has long-acting metabolites that increase the risk of hypoglycemia in the elderly. **2. Why the Other Options are Incorrect:** * **Acarbose (Alpha-glucosidase inhibitor):** It acts locally in the gut to delay carbohydrate absorption. It does not stimulate insulin secretion and therefore does not cause hypoglycemia when used as monotherapy. * **Metformin (Biguanide):** It primarily decreases hepatic gluconeogenesis and improves peripheral insulin sensitivity. It is classified as an "euglycemic" agent because it does not stimulate insulin release. * **Pioglitazone (Thiazolidinedione):** It acts via PPAR-gamma receptors to increase insulin sensitivity in muscle and adipose tissue. Like metformin, it does not promote insulin secretion and carries a minimal risk of hypoglycemia. **NEET-PG High-Yield Pearls:** * **Sulfonylureas and Meglitinides** are the only oral classes that directly cause hypoglycemia by stimulating insulin release. * **Management:** Severe sulfonylurea-induced hypoglycemia that is refractory to dextrose can be treated with **Octreotide** (a somatostatin analog that inhibits insulin release). * **Renal Caution:** Glyburide should be avoided in patients with renal impairment due to the accumulation of active metabolites; **Glipizide** is preferred in such cases.

Q: Regarding leflunomide in pregnancy, all are true except?

It is used to treat Rheumatoid arthritis in pregnancy.. **Explanation:** Leflunomide is a Disease-Modifying Antirheumatic Drug (DMARD) that acts by inhibiting **dihydroorotate dehydrogenase**, an enzyme essential for **de novo pyrimidine synthesis**. This leads to decreased T-cell proliferation and reduced inflammation. **Why Option D is the correct answer (The "Except" statement):** Leflunomide is strictly **contraindicated in pregnancy** (FDA Category X). It is highly teratogenic and is never used to treat Rheumatoid Arthritis in pregnant women. If a patient becomes pregnant while on the drug, an emergency washout procedure using **cholestyramine** is required to rapidly lower plasma levels. **Analysis of other options:** * **Option A:** Leflunomide is known to cause severe structural defects, including **hydrocephalus**, craniofacial defects, and **skeletal anomalies**, as demonstrated in animal studies and clinical reports. * **Option B:** This is the correct mechanism of action. By inhibiting pyrimidine synthesis, it arrests stimulated lymphocytes in the G1 phase of the cell cycle. * **Option C:** Leflunomide is a prodrug converted to its active metabolite, **teriflunomide (A77 1726)**. This metabolite undergoes extensive enterohepatic circulation and has a very long half-life (approx. 2 weeks). Consequently, it can take **up to 2 years** to reach plasma levels below 0.02 mg/L (the safe threshold for pregnancy) after stopping the drug. **High-Yield Clinical Pearls for NEET-PG:** * **Washout Protocol:** To accelerate elimination, **Cholestyramine** (8g, 3 times daily for 11 days) is used. * **Monitoring:** Periodic Liver Function Tests (LFTs) are mandatory due to the risk of **hepatotoxicity**. * **Pre-conception:** Both men and women should ensure drug levels are below 0.02 mg/L before attempting to conceive.

Q: Which of the following is an inhalational form of insulin?

Afrezza. **Explanation:** **Afrezza** is the correct answer as it is currently the only FDA-approved **ultra-rapid-acting inhalational insulin**. It consists of a dry powder formulation of recombinant human insulin delivered via a thumb-sized inhaler. Upon inhalation, the powder dissolves in the alveolar fluid and is rapidly absorbed into the systemic circulation, reaching peak concentrations within 12–15 minutes, mimicking the first-phase insulin release. **Analysis of Incorrect Options:** * **A. Lispro:** This is a rapid-acting insulin analogue (modified at the B28 and B29 positions). It is administered via subcutaneous injection or insulin pumps, not inhalation. * **C. Humulin:** This is a brand name for biosynthetic human insulin. It is available as Humulin R (Regular/Short-acting) and Humulin N (NPH/Intermediate-acting), both of which are injectable. * **D. Ultralente:** This is an older, long-acting crystalline zinc insulin suspension. It has largely been replaced by modern long-acting analogues like Glargine and Degludec and is administered subcutaneously. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindications:** Afrezza is strictly contraindicated in patients with chronic lung diseases such as **Asthma or COPD** due to the risk of acute bronchospasm. * **Monitoring:** Baseline **FEV1** (Forced Expiratory Volume) must be measured before starting therapy, at 6 months, and annually thereafter. * **Smoking:** It is not recommended in patients who smoke or have recently quit smoking (<6 months). * **Historical Note:** Exubera was the first inhalational insulin but was withdrawn from the market due to its bulky design and poor sales; Afrezza is the modern, compact alternative.

Q: Which antidiabetic medication is known to cause osteoporosis as an adverse drug reaction?

Pioglitazone. **Explanation:** **Pioglitazone** belongs to the **Thiazolidinedione (TZD)** class of antidiabetic drugs. These agents act as agonists for the **PPAR-γ (Peroxisome Proliferator-Activated Receptor gamma)** receptor. While PPAR-γ activation improves insulin sensitivity, it has a significant impact on bone metabolism. In the bone marrow, mesenchymal stem cells can differentiate into either adipocytes or osteoblasts. PPAR-γ activation shifts this balance toward **adipogenesis** (fat cell formation) while inhibiting **osteoblastogenesis** (bone-forming cell formation). This leads to decreased bone formation, reduced bone mineral density, and an increased risk of fractures, particularly in postmenopausal women. **Analysis of Incorrect Options:** * **Metformin (Biguanide):** Generally considered bone-neutral or potentially bone-protective. Its primary side effects are gastrointestinal (diarrhea, abdominal cramps) and lactic acidosis. * **Glibenclamide (Sulfonylurea):** Works by stimulating insulin secretion from pancreatic beta cells. It is primarily associated with hypoglycemia and weight gain, not osteoporosis. * **Acarbose (Alpha-glucosidase inhibitor):** Acts locally in the intestine to delay carbohydrate absorption. Its side effects are limited to the GI tract (flatulence, bloating). **High-Yield Clinical Pearls for NEET-PG:** * **TZD Side Effects:** Weight gain, **fluid retention/edema** (contraindicated in NYHA Class III/IV heart failure), and increased risk of **bladder cancer** (specifically associated with Pioglitazone). * **Fracture Site:** Fractures associated with TZDs often occur in distal upper or lower limbs (humerus, radius, feet) rather than the typical hip or spine fractures seen in involutional osteoporosis. * **Other drugs causing Osteoporosis:** Glucocorticoids (most common), Heparin (long-term), Phenytoin, and Proton Pump Inhibitors (PPIs).

Q: All of the following decrease bone resorption in osteoporosis except?

Teriparatide. ### Explanation The management of osteoporosis involves two main classes of drugs: **Antiresorptive agents** (which inhibit osteoclast activity) and **Anabolic agents** (which stimulate osteoblast activity to form new bone). **Why Teriparatide is the correct answer:** Teriparatide is a recombinant form of human **Parathyroid Hormone (PTH)**. While continuous high levels of PTH (as seen in hyperparathyroidism) cause bone resorption, **intermittent (once-daily) administration** of Teriparatide stimulates osteoblastic activity more than osteoclastic activity. Therefore, it is classified as an **Anabolic agent** (bone-forming) rather than an antiresorptive agent. **Analysis of incorrect options:** * **Alendronate & Etidronate (Options A & B):** These are **Bisphosphonates**. They work by concentrating at sites of active bone remodeling and inhibiting osteoclast-mediated bone resorption. Alendronate is a potent nitrogen-containing bisphosphonate, while Etidronate is a first-generation non-nitrogenous bisphosphonate. * **Strontium Ranelate (Option C):** This drug has a **dual mechanism of action**. It both inhibits bone resorption (by inhibiting osteoclast differentiation) and stimulates bone formation (by promoting osteoblast proliferation). Since it does decrease resorption, it does not fit the "except" criteria. **High-Yield Clinical Pearls for NEET-PG:** * **Teriparatide Side Effects:** Hypercalcemia, hyperuricemia, and a theoretical risk of **Osteosarcoma** (avoid in patients with Paget’s disease or prior radiation). * **Bisphosphonates:** Must be taken on an empty stomach with a full glass of water, and the patient must remain upright for 30 minutes to prevent **erosive esophagitis**. * **Denosumab:** A monoclonal antibody against **RANKL**; it is a potent antiresorptive agent. * **Raloxifene:** A SERM that acts as an estrogen agonist in bone (antiresorptive) but an antagonist in the breast and uterus.

Q: Newer progestational contraceptives primarily act by:

Inhibiting ovulation. **Explanation:** The primary mechanism of action for hormonal contraceptives depends on the dose and type of progestin used. **Why Option D is Correct:** While older, low-dose "mini-pills" (Progestin-Only Pills or POPs) primarily worked by altering cervical mucus, **newer progestational contraceptives** (such as Desogestrel, Drospirenone, and long-acting injectables/implants like DMPA) contain more potent progestins or higher systemic doses. These newer agents consistently achieve blood levels high enough to suppress the hypothalamic-pituitary-ovarian axis. They inhibit the mid-cycle **LH surge**, thereby **inhibiting ovulation**, which is the most reliable method of preventing pregnancy. **Why Other Options are Incorrect:** * **Options A, B, and C:** These represent "peripheral" mechanisms. While progestins do make the cervical mucus thick and hostile to sperm (Option C), render the endometrium out of sync for implantation (Option B), and alter tubal motility (Option A), these are considered **secondary or backup mechanisms** for newer-generation progestins. In older POPs (e.g., Norethindrone), Option C was the primary mechanism because they did not consistently suppress ovulation. **NEET-PG High-Yield Pearls:** * **Combined Oral Contraceptive Pills (COCPs):** Always act primarily by inhibiting ovulation (Estrogen inhibits FSH; Progestin inhibits LH). * **DMPA (Depot Medroxyprogesterone Acetate):** A highly effective injectable that acts primarily by suppressing ovulation for 3 months. * **Centchroman (Saheli):** A non-steroidal SERM (Selective Estrogen Receptor Modulator) that acts by preventing implantation (making the uterus "unfriendly"). * **Emergency Contraceptive (Levonorgestrel 1.5mg):** Primarily acts by delaying or inhibiting ovulation if taken before the LH surge.

Q: Which of the following is an antiandrogenic drug?

Ketoconazole. **Explanation:** **Ketoconazole** is the correct answer because it is a potent inhibitor of steroidogenesis. While primarily used as an antifungal, it inhibits the enzyme **17,20-desmolase** (and to a lesser extent, CYP11A1/side-chain cleavage enzyme), which is essential for the conversion of cholesterol into adrenal and gonadal androgens. By blocking this pathway, it significantly reduces testosterone levels. Clinically, this "side effect" is utilized in the management of advanced prostate cancer and Cushing’s syndrome. **Analysis of Incorrect Options:** * **Fluconazole & Itraconazole (Options A & B):** These are triazole antifungals. Unlike the imidazole ketoconazole, triazoles are highly selective for fungal CYP450 (lanosterol 14α-demethylase) and have negligible effects on human steroid hormone synthesis. Therefore, they do not possess antiandrogenic properties. * **Terbinafine (Option D):** This is an allylamine that inhibits **squalene epoxidase**. Its mechanism is entirely different from the azoles and does not involve the cytochrome P450 system or steroid hormone pathways. **High-Yield Clinical Pearls for NEET-PG:** * **Adverse Effect:** Due to its antiandrogenic activity, ketoconazole frequently causes **gynecomastia**, loss of libido, and erectile dysfunction in males. * **Drug Interactions:** Ketoconazole is a potent **CYP3A4 inhibitor**, leading to numerous drug-drug interactions (e.g., increasing levels of statins or warfarin). * **Hepatotoxicity:** It carries a black box warning for severe liver injury; hence, it is rarely used as a first-line antifungal today. * **Other Antiandrogens to Remember:** Finasteride (5α-reductase inhibitor), Flutamide (Androgen receptor antagonist), and Spironolactone (Aldosterone antagonist with antiandrogenic effects).

Q: Octreotide is used in all except which of the following conditions?

Glioma. **Explanation:** **Octreotide** is a potent, long-acting synthetic analog of **Somatostatin**. It acts as a universal inhibitor of secretory hormones by binding to somatostatin receptors (SSTR-2 and SSTR-5). **Why Glioma is the correct answer:** Gliomas are primary tumors of the glial cells in the brain. Unlike neuroendocrine tumors, gliomas do not typically express the specific somatostatin receptors targeted by octreotide, nor is their growth primarily driven by hormones that octreotide inhibits. Therefore, octreotide has no established therapeutic role in the management of **Glioma**. **Analysis of incorrect options:** * **Glucagonoma:** This is an alpha-cell tumor of the pancreas. Octreotide effectively inhibits the release of glucagon, helping to resolve the characteristic skin rash (necrolytic migratory erythema). * **Insulinoma:** Octreotide can be used to inhibit insulin secretion in these beta-cell tumors, although its efficacy varies depending on the receptor subtype expression of the specific tumor. * **Carcinoid Syndrome:** Octreotide is the **gold standard** treatment for managing the secretory diarrhea and flushing associated with carcinoid tumors by inhibiting the release of serotonin and other peptides. **Clinical Pearls for NEET-PG:** * **Other Uses:** Acromegaly (inhibits GH), secretory diarrhea in VIPoma, and acute management of bleeding esophageal varices (causes splanchnic vasoconstriction). * **Side Effects:** The most high-yield side effect is the formation of **gallstones (cholelithiasis)** due to the inhibition of cholecystokinin (CCK) and subsequent gallbladder stasis. * **Mechanism:** It is significantly more potent and has a longer half-life (approx. 1.5 hours) compared to natural somatostatin (approx. 2 minutes).

Q: Which of the following synthetic steroids shows predominantly mineralocorticoid action?

Fludrocortisone. The correct answer is **Fludrocortisone**. **1. Why Fludrocortisone is correct:** Fludrocortisone is a potent synthetic corticosteroid. While it possesses both glucocorticoid and mineralocorticoid activities, its **mineralocorticoid potency is significantly higher** (approximately 250 times that of hydrocortisone). In clinical practice, it is used almost exclusively for its mineralocorticoid effects—promoting sodium retention and potassium excretion—making it the drug of choice for replacement therapy in primary adrenal insufficiency (Addison’s disease). **2. Why the other options are incorrect:** * **Hydrocortisone:** This is the synthetic form of cortisol. It has a 1:1 ratio of glucocorticoid to mineralocorticoid activity. While it has mineralocorticoid action, it is not "predominantly" mineralocorticoid compared to fludrocortisone. [1] * **Spironolactone:** This is a **mineralocorticoid receptor antagonist** (potassium-sparing diuretic). It blocks the action of aldosterone rather than mimicking it. * **Dexamethasone:** This is a highly potent **pure glucocorticoid**. It has maximal anti-inflammatory activity with virtually zero mineralocorticoid (salt-retaining) properties. [1, 2] **3. High-Yield NEET-PG Pearls:** * **Relative Potency Table:** * *Dexamethasone/Betamethasone:* Highest Glucocorticoid potency; Zero Mineralocorticoid potency. [1, 2] * *Fludrocortisone:* Highest Mineralocorticoid potency. * *Aldosterone:* Natural mineralocorticoid (not used clinically due to high first-pass metabolism). [1] * **Clinical Use:** Fludrocortisone is used in **Addison’s disease** and **Congenital Adrenal Hyperplasia (CAH)** to prevent salt wasting. * **Side Effects:** Excessive doses lead to hypertension, edema, and hypokalemia.

Question 1

A 75-year-old woman with diabetes is taking oral antidiabetic drugs. She goes without eating for 18 hours, and her serum glucose concentration is 48 mg/dL (hypoglycemic) upon arrival at the emergency department, where she is deemed to be in critical condition. Which of the following drugs most likely aggravated this fasting hypoglycemia?

Accepted Answer

Glyburide

Answer

Acarbose

Answer

Metformin

Answer

Pioglitazone

Question 2

Regarding leflunomide in pregnancy, all are true except?

Accepted Answer

It is used to treat Rheumatoid arthritis in pregnancy.

Answer

It can cause hydrocephalus and skeletal anomalies in the fetus.

Answer

It is a pyrimidine synthesis inhibitor.

Answer

Its active metabolite can be detected in plasma for up to 2 years after discontinuation.

Question 3

Which of the following is an inhalational form of insulin?

Accepted Answer

Afrezza

Answer

Lispro

Answer

Humulin

Answer

Ultralente

Question 4

Which antidiabetic medication is known to cause osteoporosis as an adverse drug reaction?

Accepted Answer

Pioglitazone

Answer

Metformin

Answer

Glibenclamide

Answer

Acarbose

Question 5

100 mg of hydrocortisone is equivalent to how much methylprednisolone?

Accepted Answer

20 mg methylprednisolone

Answer

20 mg cortisone acetate

Answer

10 mg dexamethasone

Answer

10 mg prednisone

Question 6

All of the following decrease bone resorption in osteoporosis except?

Accepted Answer

Teriparatide

Answer

Alendronate

Answer

Etidronate

Answer

Strontium

Question 7

Newer progestational contraceptives primarily act by:

Accepted Answer

Inhibiting ovulation

Answer

Altering oviductal motility

Answer

Modifying the uterine endometrium

Answer

Changing cervical mucus properties

Question 8

Which of the following is an antiandrogenic drug?

Accepted Answer

Ketoconazole

Answer

Fluconazole

Answer

Itraconazole

Answer

Terbinafine

Question 9

Octreotide is used in all except which of the following conditions?

Accepted Answer

Glioma

Answer

Glucagonoma

Answer

Insulinoma

Answer

Carcinoid syndrome

Question 10

Which of the following synthetic steroids shows predominantly mineralocorticoid action?

Accepted Answer

Fludrocortisone

Answer

Hydrocortisone

Answer

Spironolactone

Answer

Dexamethasone

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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