Endocrine Pharmacology Practice Questions

Q: Which of the following is a side effect of Octreotide?

Cholesterol gallstones. **Explanation:** **Octreotide** is a synthetic long-acting analogue of **Somatostatin**. It acts by binding to somatostatin receptors (SSTR-2 and SSTR-5), leading to the inhibition of various hormones, including Growth Hormone (GH), Glucagon, Insulin, and Gastrin. **Why Cholesterol Gallstones occur (Correct Answer):** Octreotide significantly inhibits the secretion of **Cholecystokinin (CCK)** and reduces gallbladder contractility. This leads to biliary stasis and increased concentration of bile. Long-term use (usually >6 months) results in the formation of biliary sludge and **cholesterol gallstones** in up to 50% of patients. **Analysis of Incorrect Options:** * **A. Arrhythmias:** While bradycardia can occur, it is not the most characteristic or frequently tested side effect compared to biliary issues. * **C. Hyperglycemia:** Octreotide inhibits both insulin and glucagon. While it can cause transient hyperglycemia, it more commonly causes **hypoglycemia** or has a neutral effect on blood glucose in acromegalic patients. * **D. Diarrhea:** Octreotide actually causes **steatorrhea** (fatty stools) due to the inhibition of pancreatic enzymes, but it is clinically used to *treat* secretory diarrhea (e.g., in VIPoma or Carcinoid syndrome). **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Octreotide is the DOC for **Esophageal Variceal Bleeding** (causes splanchnic vasoconstriction) and **Acromegaly**. * **Diagnostic Use:** Radiolabeled octreotide (OctreoScan) is used for localizing neuroendocrine tumors. * **Key Side Effects:** Steatorrhea, nausea, and abdominal cramps (usually transient), and cholelithiasis (long-term).

Q: Which of the following does not cause hypoglycemia?

Metformin. ### Explanation The correct answer is **C. Metformin**. **1. Why Metformin is the correct answer:** Metformin belongs to the **Biguanide** class of oral hypoglycemic agents. Its primary mechanism of action is to decrease hepatic glucose production (gluconeogenesis) and improve peripheral insulin sensitivity. Crucially, Metformin is an **euglycemic** agent; it does not stimulate the pancreas to release insulin (it is not an insulin secretagogue). Therefore, when used as monotherapy, it does not cause hypoglycemia because it does not increase circulating insulin levels beyond physiological needs. **2. Why the other options are incorrect:** * **A. Insulin:** This is the most potent glucose-lowering agent. It directly promotes glucose uptake into cells and inhibits glucose production. An overdose or mismatched timing with meals leads to direct hypoglycemia. * **B. Glimepiride & D. Gliclazide:** These are **Sulfonylureas** (2nd and 3rd generation, respectively). They act by closing ATP-sensitive K+ channels in pancreatic beta cells, leading to depolarization and **stimulated insulin release** regardless of blood glucose levels. This "forced" insulin secretion is a major cause of drug-induced hypoglycemia. **3. NEET-PG High-Yield Pearls:** * **"Euglycemics":** Besides Metformin, **Thiazolidinediones (Pioglitazone)** and **DPP-4 inhibitors (Sitagliptin)** have a low risk of hypoglycemia when used alone. * **Metformin Side Effects:** The most common side effects are GI-related (diarrhea, abdominal pain). The most serious, though rare, is **Lactic Acidosis**. It is contraindicated in patients with significant renal impairment (eGFR <30 mL/min). * **Drug of Choice:** Metformin remains the first-line drug for Type 2 Diabetes Mellitus due to its weight-neutrality and cardiovascular safety.

Q: For the treatment of cerebral edema due to a brain tumor, which corticosteroid is preferred?

Dexamethasone. **Explanation:** **Dexamethasone** is the drug of choice for managing vasogenic cerebral edema associated with brain tumors. The primary reason for its preference is its **minimal mineralocorticoid activity**. Unlike other steroids, dexamethasone does not cause significant sodium and water retention. In the context of increased intracranial pressure (ICP), avoiding fluid retention is critical to prevent further worsening of the edema. Additionally, it has a **long half-life** (36–72 hours) and **high potency**, allowing for effective symptom control with less frequent dosing. It also crosses the blood-brain barrier effectively to reduce capillary permeability. **Analysis of Incorrect Options:** * **A. Hydrocortisone:** It possesses significant mineralocorticoid activity, leading to salt and water retention, which can exacerbate cerebral edema. It is primarily used for replacement therapy in adrenal insufficiency. * **B. Prednisolone:** While it has more potent anti-inflammatory effects than hydrocortisone, it still retains moderate mineralocorticoid activity, making it less ideal than dexamethasone for CNS edema. * **C. Triamcinolone:** Although it has zero mineralocorticoid activity, it is generally used for topical, intra-articular, or intralesional purposes and is not the standard of care for acute reduction of ICP. **High-Yield Clinical Pearls for NEET-PG:** * **Vasogenic Edema:** Dexamethasone is specifically effective for *vasogenic* edema (tumors, abscesses); it is less effective for *cytotoxic* edema (infarction). * **Potency:** Dexamethasone is roughly 25–30 times more potent than hydrocortisone. * **ACTH Suppression:** Due to its long duration of action, dexamethasone causes significant suppression of the Hypothalamic-Pituitary-Adrenal (HPA) axis. * **Diagnostic Use:** It is also used in the **Dexamethasone Suppression Test** to diagnose Cushing’s syndrome.

Q: Which drug is used to treat tremors in hyperthyroidism?

Propranolol. **Explanation:** In hyperthyroidism (Thyrotoxicosis), there is an over-expression of beta-adrenergic receptors and increased sensitivity to catecholamines. This leads to symptoms of sympathetic overactivity, such as **tremors, palpitations, tachycardia, and anxiety.** **1. Why Propranolol is the Correct Answer:** Propranolol is a non-selective beta-blocker that effectively antagonizes these beta-receptors, providing rapid symptomatic relief from tremors and tachycardia. Beyond symptom control, Propranolol has a unique advantage: at high doses, it **inhibits the peripheral conversion of T4 (Thyroxine) to the more active T3 (Triiodothyronine)** by inhibiting the enzyme 5'-deiodinase. This makes it the drug of choice for immediate management in thyrotoxic crisis (thyroid storm). **2. Why Incorrect Options are Wrong:** * **Adrenaline & Noradrenaline:** These are catecholamines that stimulate adrenergic receptors. Administering them would worsen the symptoms of hyperthyroidism and could potentially precipitate a fatal cardiac event or thyroid storm. * **Dopamine:** This is a precursor to norepinephrine. It increases heart rate and blood pressure, which would exacerbate the hypermetabolic state of the patient. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice for Thyroid Storm:** Propranolol (for symptoms/T4-T3 conversion) + PTU (to block synthesis and conversion). * **Cardioselective alternatives:** If a patient has co-existing asthma (where Propranolol is contraindicated), cardioselective beta-blockers like **Atenolol or Metoprolol** are used, though they lack the T4-to-T3 conversion inhibitory effect. * **Esmolol:** Used intravenously in emergency settings for rapid heart rate control in thyrotoxicosis due to its ultra-short half-life.

Q: GnRH analogue may be given in all of the following conditions except:

Endometrial cancer. The correct answer is **Endometrial cancer** because GnRH analogues are not a standard or primary treatment for this specific malignancy. Endometrial cancer is primarily managed through surgery, radiation, and progestins (like Medroxyprogesterone acetate), which counteract the effects of estrogen on the endometrium. **Mechanism of Action:** GnRH analogues (e.g., Leuprolide, Goserelin, Nafarelin) act as agonists at the GnRH receptor [2]. While an initial "flare" occurs, **continuous administration** leads to downregulation and desensitization of GnRH receptors in the pituitary [3]. This results in a state of **hypogonadotropic hypogonadism** (chemical castration), effectively lowering LH, FSH, and sex steroids (testosterone and estrogen). **Why other options are incorrect:** * **Prostate cancer:** Since prostate cancer is androgen-dependent, GnRH analogues are a first-line therapy to reduce testosterone levels [1]. * **Uterine fibromyoma:** These are estrogen-dependent tumors. GnRH analogues shrink the fibroids by inducing a hypoestrogenic state, often used pre-operatively to reduce blood loss [1]. * **Precocious Puberty:** GnRH analogues are the treatment of choice for central precocious puberty to suppress the premature activation of the hypothalamic-pituitary-gonadal axis. **NEET-PG High-Yield Pearls:** * **Pulsatile administration** of GnRH is used to treat **Infertility** (stimulates FSH/LH) [2]. * **Continuous administration** is used for **hormone-dependent conditions** (Endometriosis, PCOD, Breast cancer, Prostate cancer) [3]. * **Side Effects:** Hot flashes, loss of libido, and osteoporosis (due to long-term estrogen deficiency). * **Note:** GnRH **antagonists** (e.g., Cetrorelix, Degarelix) are preferred when the initial "testosterone flare" must be avoided [4].

Question 1

What is the drug of choice for post-menopausal osteoporosis?

Accepted Answer

Alendronate

Answer

Raloxifene

Answer

Tamoxifene

Answer

Estrogen

Question 2

What is the difference between carbimazole and propylthiouracil?

Accepted Answer

Carbimazole does not inhibit the peripheral conversion of T4 to T3.

Answer

Carbimazole is less potent.

Answer

Carbimazole is shorter acting.

Answer

Carbimazole does not produce an active metabolite.

Question 3

Niacin is dangerous in diabetes mellitus because:

Accepted Answer

It causes insulin resistance

Answer

It causes sudden hypoglycemia

Answer

It decreases glucagon secretion

Answer

It decreases the effect of other oral hypoglycemic agents

Question 4

Adrenal suppression is caused by all of the following drugs EXCEPT?

Accepted Answer

Erythromycin

Answer

Ketoconazole

Answer

Rifampicin

Answer

Phenytoin

Question 5

Which of the following is a side effect of Octreotide?

Accepted Answer

Cholesterol gallstones

Answer

Arrhythmias

Answer

Hyperglycemia

Answer

Diarrhea

Question 6

Which of the following does not cause hypoglycemia?

Accepted Answer

Metformin

Answer

Insulin

Answer

Glimepiride

Answer

Gliclazide

Question 7

For the treatment of cerebral edema due to a brain tumor, which corticosteroid is preferred?

Accepted Answer

Dexamethasone

Answer

Hydrocortisone

Answer

Prednisolone

Answer

Triamcinolone

Question 8

Which of the following disorders is NOT aggravated by corticosteroid therapy?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Diabetes mellitus

Answer

Hypertension

Answer

Peptic ulcer

Question 9

Which drug is used to treat tremors in hyperthyroidism?

Accepted Answer

Propranolol

Answer

Adrenaline

Answer

Noradrenaline

Answer

Dopamine

Question 10

GnRH analogue may be given in all of the following conditions except:

Accepted Answer

Endometrial cancer

Answer

Prostate cancer

Answer

Uterine fibromyoma

Answer

Precocious puberty

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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