Endocrine Pharmacology Practice Questions

Q: All are true regarding selective estrogen receptor downregulator (SERD), Fulvestrant, except?

Is slower, short-acting, and less safe than SERMs.. **Explanation** **Fulvestrant** is a unique hormonal agent classified as a **Selective Estrogen Receptor Downregulator (SERD)** [1]. Unlike SERMs (e.g., Tamoxifen), which have agonist effects in some tissues and antagonist effects in others, Fulvestrant is a **pure estrogen antagonist** with no agonist activity [3]. **Why Option C is the correct (False) statement:** Fulvestrant is actually **longer-acting** and has a **better safety profile** compared to many SERMs. It has a long half-life (approx. 40 days), allowing for infrequent dosing [1]. Furthermore, because it lacks the partial agonist activity of Tamoxifen, it does **not** increase the risk of endometrial cancer or venous thromboembolism, making it safer in those specific regards [2]. **Analysis of other options:** * **Option A:** It is FDA-approved for the treatment of hormone receptor-positive (HR+) **advanced or metastatic breast cancer**, particularly in postmenopausal women who have progressed on other anti-estrogen therapies [3]. * **Option B:** It binds to estrogen receptors (ER) with high affinity, blocking estrogen binding and triggering the **degradation (downregulation)** of the receptor protein [1]. Thus, it acts as a pure antagonist. * **Option D:** Due to its pharmacokinetic profile, it is administered as a **500 mg intramuscular (IM) injection** once monthly (after an initial loading dose) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** "Bind, Block, Degrade." It leads to a total reduction in the number of estrogen receptors in the cell [1]. * **Indication:** Second-line therapy for metastatic breast cancer after Tamoxifen or Aromatase Inhibitor failure [3]. * **Side Effects:** Most common are injection site pain, hot flashes, and nausea. * **Comparison:** Unlike Tamoxifen (SERM), Fulvestrant does **not** carry a risk of uterine (endometrial) hyperplasia [2].

Q: Growth Hormone may be beneficial in which of the following conditions, except?

Laron type dwarfism.. ### Explanation **1. Why Laron Type Dwarfism is the Correct Answer:** Laron dwarfism is characterized by **Growth Hormone (GH) receptor insensitivity**. In this condition, GH levels are actually normal or elevated, but the receptors are non-functional, leading to a failure in the production of **IGF-1 (Insulin-like Growth Factor-1)**. Since the defect lies at the receptor level, administering exogenous Growth Hormone will have no effect. The treatment of choice for Laron dwarfism is **Mecasermin** (recombinant IGF-1). **2. Analysis of Incorrect Options:** * **Constitutional Growth Delay:** GH can be used to increase final adult height in children who are significantly below the growth curve, even if they are not GH deficient. * **Osteoporosis:** GH stimulates osteoblast activity and increases bone mineral density. While not a first-line treatment, it is physiologically beneficial and approved for use in GH-deficient adults with low bone mass. * **Panhypopituitarism:** This involves a deficiency of all anterior pituitary hormones, including GH. Replacement therapy with recombinant GH (Somatropin) is a standard indication to restore normal growth and metabolic function. **3. High-Yield Clinical Pearls for NEET-PG:** * **Somatropin:** Recombinant human GH used for GH deficiency, Turner syndrome, Prader-Willi syndrome, and Chronic Renal Failure. * **Somatomedin C:** Another name for IGF-1; it mediates most of the growth-promoting effects of GH. * **Side Effects of GH:** Slipped capital femoral epiphysis, pseudotumor cerebri, and hyperglycemia (diabetogenic potential). * **Contraindication:** GH should not be used in patients with active malignancy or closed epiphyses.

Q: All of the following drugs can be used for diabetes insipidus, except:

Furosemide. **Explanation:** The correct answer is **Furosemide**. Furosemide is a loop diuretic that inhibits the Na⁺-K⁺-2Cl⁻ cotransporter in the thick ascending limb of the loop of Henle. This action abolishes the corticomedullary osmotic gradient, preventing the kidney from concentrating urine. Consequently, it causes **diuresis** (increased water loss), which would worsen the polyuria seen in Diabetes Insipidus (DI). **Why the other options are used in DI:** * **Amiloride (Option A):** This is the drug of choice for **Lithium-induced Nephrogenic DI**. It blocks the epithelial sodium channels (ENaC) in the collecting duct, preventing lithium from entering the cells and exerting its toxic effect. * **Chlorpropamide (Option C):** A first-generation sulfonylurea used in **Central DI**. It sensitizes the renal tubules to the action of ADH and may also stimulate the release of ADH from the hypothalamus. * **Carbamazepine (Option D):** Primarily an anticonvulsant, it is used in **Central DI** because it stimulates the release of endogenous ADH. **Clinical Pearls for NEET-PG:** 1. **Thiazide Diuretics:** Paradoxically used in Nephrogenic DI. They cause mild ECF volume depletion, leading to increased proximal tubular reabsorption of salt and water, which reduces the volume of filtrate reaching the distal nephron. 2. **Drug of Choice (DOC):** Desmopressin (dDAVP) is the DOC for Central DI. 3. **Indomethacin:** Sometimes used in Nephrogenic DI as it inhibits prostaglandins (which are natural ADH antagonists).

Q: All of the following are true regarding the use of iodine, except:

Its use is contraindicated in hyperthyroidism.. **Explanation:** The correct answer is **D**, as iodine is **not** contraindicated in hyperthyroidism; rather, it is used strategically in specific clinical scenarios. **1. Why Option D is the correct answer (The Exception):** Iodine (usually as Lugol’s iodine or potassium iodide) is a standard treatment for hyperthyroidism in two specific cases: **Pre-operative preparation** for thyroidectomy (to decrease the vascularity and size of the gland) and **Thyroid Storm** (to rapidly block hormone release). Therefore, stating it is contraindicated is medically incorrect. **2. Analysis of other options:** * **Option A (True):** High doses of iodine acutely inhibit the proteolysis of thyroglobulin, thereby blocking the **release** of T3 and T4 into the circulation. This is the fastest-acting mechanism to lower thyroid levels. * **Option B (True):** This refers to the **Wolff-Chaikoff effect**, where high plasma iodide concentrations cause a transient inhibition of the organic binding of iodine (organification), stopping the synthesis of iodotyrosine and iodothyronine. * **Option C (True):** **Iodism** is a chronic toxicity resulting from iodine use. Symptoms include a metallic taste, burning sensation in the mouth, sneezing (coryza), and swelling of the eyelids/salivary glands. **Clinical Pearls for NEET-PG:** * **The Escape Phenomenon:** The Wolff-Chaikoff effect is transient; the thyroid "escapes" this inhibition after 10–14 days. Thus, iodine should not be used as long-term monotherapy. * **Jod-Basedow Phenomenon:** In contrast to the Wolff-Chaikoff effect, iodine administration in a deficient patient can sometimes *induce* hyperthyroidism. * **Amiodarone:** This antiarrhythmic drug contains high iodine content and can cause both hyper- and hypothyroidism.

Q: Flushing is common in patients taking which of the following oral hypoglycemic drugs with alcohol?

Chlorpropamide. ### Explanation **1. Why Chlorpropamide is Correct:** Chlorpropamide is a first-generation sulfonylurea known for causing a **Disulfiram-like reaction** when consumed with alcohol. This occurs because chlorpropamide inhibits the enzyme **aldehyde dehydrogenase**, leading to the accumulation of acetaldehyde in the blood. High levels of acetaldehyde trigger systemic vasodilation, resulting in symptoms such as intense flushing (especially of the face), nausea, tachycardia, and headache. This specific phenomenon is often referred to as **Chlorpropamide-Alcohol Flush (CPAF)**. **2. Why the Other Options are Incorrect:** * **Phenformin (B):** This is a biguanide (like metformin) that was withdrawn from the market primarily due to a high risk of **lactic acidosis**. While it interacts with alcohol to increase lactic acid levels, it does not typically cause a disulfiram-like flushing reaction. * **Glibenclamide (C) & Tolazamide (D):** These are second-generation and first-generation sulfonylureas, respectively. While all sulfonylureas can theoretically cause mild disulfiram-like reactions, the incidence is significantly lower than with chlorpropamide. Glibenclamide, in particular, has a very low propensity for this side effect. **3. High-Yield Clinical Pearls for NEET-PG:** * **Chlorpropamide** has the longest half-life among sulfonylureas (~36 hours) and is most likely to cause **SIADH** (dilutional hyponatremia) and prolonged hypoglycemia. * **Other drugs causing Disulfiram-like reactions:** Metronidazole (most common), Tinidazole, Griseofulvin, Cefotetan, and Procarbazine. * **Management:** The reaction is self-limiting; the primary management is avoidance of alcohol while on these medications.

Q: Which dopamine agonist is used in the management of diabetes mellitus?

Bromocriptine. **Explanation:** **Bromocriptine** is a potent dopamine D2 receptor agonist. While primarily known for treating hyperprolactinemia and Parkinson’s disease, a specific quick-release (QR) formulation of Bromocriptine is FDA-approved for the management of **Type 2 Diabetes Mellitus**. **Mechanism of Action:** In patients with Type 2 DM, there is often a decrease in dopaminergic tone in the hypothalamus during the morning. Bromocriptine QR, when administered within two hours of waking, acts on the circadian rhythm to increase hypothalamic dopaminergic activity. This results in a reduction of sympathetic outflow, leading to decreased hepatic glucose production (gluconeogenesis), reduced insulin resistance, and lower free fatty acid levels without increasing insulin secretion. **Analysis of Incorrect Options:** * **A. Metformin:** This is a Biguanide, not a dopamine agonist. It is the first-line drug for Type 2 DM, acting primarily by activating AMPK to inhibit hepatic gluconeogenesis. * **C. Cabergoline:** Although it is a long-acting dopamine agonist used for prolactinomas, it is **not** approved or used for the management of glycemic control in diabetes. * **D. Vanadium salts:** These are trace elements that have "insulin-mimetic" properties but are not dopamine agonists and are not used in standard clinical practice due to toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **Bromocriptine QR** is the only dopamine agonist approved for DM. * It does **not** cause hypoglycemia or weight gain, making it unique among many oral hypoglycemics. * It is also known to reduce the risk of major adverse cardiovascular events (MACE). * **Side effects:** Nausea, dizziness, and orthostatic hypotension are common during initiation.

Q: Which of the following is an anti-progesterone drug?

Mifepristone. **Explanation:** **Mifepristone (RU-486)** is the correct answer because it is a potent **competitive progesterone receptor antagonist**. It binds to progesterone receptors with higher affinity than endogenous progesterone, preventing the hormone from maintaining the decidua. This leads to the detachment of the blastocyst and sensitization of the uterus to prostaglandins. **Analysis of Incorrect Options:** * **Cyproterone:** This is an **anti-androgen** (androgen receptor antagonist) with weak progestational activity. It is used in the management of hirsutism, acne, and precocious puberty. * **Spironolactone:** Primarily a potassium-sparing diuretic, it also acts as an **aldosterone antagonist** and has significant anti-androgenic properties. It is not an anti-progestin. * **Tamoxifen:** This is a **Selective Estrogen Receptor Modulator (SERM)**. It acts as an antagonist in the breast (used in breast cancer) but as an agonist in the bone and endometrium. **High-Yield Clinical Pearls for NEET-PG:** * **Medical Abortion Regimen:** Mifepristone (200 mg orally) is followed 36–48 hours later by **Misoprostol** (400–800 mcg) to induce uterine contractions. This is effective up to 7-9 weeks of gestation. * **Cushing’s Syndrome:** Mifepristone is also FDA-approved for controlling hyperglycemia in patients with endogenous Cushing’s syndrome (due to its **glucocorticoid receptor antagonism** at high doses). * **Emergency Contraception:** Mifepristone can be used as a single dose for emergency contraception (though Levonorgestrel and Ulipristal are more common). * **Ulipristal:** Another important Selective Progesterone Receptor Modulator (SPRM) used for emergency contraception and uterine fibroids.

Question 1

All are true regarding selective estrogen receptor downregulator (SERD), Fulvestrant, except?

Accepted Answer

Is slower, short-acting, and less safe than SERMs.

Answer

Used for the treatment of advanced breast cancer.

Answer

Is a selective estrogen antagonist.

Answer

Administered as a once-monthly intramuscular dose.

Question 2

What is the most important side effect of insulin?

Accepted Answer

Hypoglycaemia

Answer

Lipodystrophy

Answer

Insulin resistance

Answer

Antibodies to insulin

Question 3

Growth Hormone may be beneficial in which of the following conditions, except?

Accepted Answer

Laron type dwarfism.

Answer

In children with constitutional growth delay.

Answer

In treatment of osteoporosis.

Answer

Panhypopituitarism.

Question 4

All of the following drugs can be used for diabetes insipidus, except:

Accepted Answer

Furosemide

Answer

Amiloride

Answer

Chlorpropamide

Answer

Carbamazepine

Question 5

All of the following are true regarding the use of iodine, except:

Accepted Answer

Its use is contraindicated in hyperthyroidism.

Answer

It inhibits the release of thyroid hormones.

Answer

It causes acute inhibition of iodotyrosine and iodothyronine synthesis.

Answer

It can cause iodism.

Question 6

Flushing is common in patients taking which of the following oral hypoglycemic drugs with alcohol?

Accepted Answer

Chlorpropamide

Answer

Phenformin

Answer

Glibenclamide

Answer

Tolazamide

Question 7

Which dopamine agonist is used in the management of diabetes mellitus?

Accepted Answer

Bromocriptine

Answer

Metformin

Answer

Cabergoline

Answer

Vanadium salts

Question 8

Which drug acts on V2 receptors and is used in diabetes insipidus?

Accepted Answer

Desmopressin

Answer

Telypressin

Answer

Vasopressin

Answer

Pralispressin

Question 9

Which of the following is an anti-progesterone drug?

Accepted Answer

Mifepristone

Answer

Cyproterone

Answer

Spironolactone

Answer

Tamoxifen

Question 10

Which of the following statements regarding finasteride is FALSE?

Accepted Answer

It blocks the conversion of testosterone to dihydrotestosterone.

Answer

It is used in the treatment of benign prostatic hyperplasia.

Answer

Impotence is well-documented after its use.

Answer

It is a 5-alpha reductase inhibitor.

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?