Endocrine Pharmacology Practice Questions

Q: Which of the following contains emergency contraception?

Levonorgestrel. **Levonorgestrel (LNG)** is the gold standard for hormonal emergency contraception [1]. It is a second-generation synthetic progestin. When used as emergency contraception (the "morning-after pill"), it is typically administered as a single **1.5 mg dose** within 72 hours of unprotected intercourse [1]. Its primary mechanism of action is the **delay or inhibition of ovulation** by suppressing the LH surge. It is not an abortifacient and is ineffective once implantation has occurred. **Analysis of Incorrect Options:** * **Cyproterone:** An anti-androgenic progestin used primarily in the treatment of severe acne, hirsutism (PCOS), and as part of combined oral contraceptives (e.g., Diane-35) [2]. * **Desogestrel:** A third-generation progestin commonly used in "mini-pills" (Progestogen-only pills) for daily contraception [2]. It is not used in the high doses required for emergency intervention. * **Medroxyprogesterone (MPA):** Primarily used as an injectable contraceptive (**DMPA/Antara**) given every 3 months (150 mg IM). It provides long-term depot contraception rather than emergency post-coital prevention. **High-Yield Clinical Pearls for NEET-PG:** * **Yuzpe Regimen:** An older method using high doses of combined OCPs (Ethinylestradiol + Levonorgestrel); it is less effective and causes more nausea than LNG alone. * **Ulipristal Acetate:** A selective progesterone receptor modulator (SPRM) that is now considered more effective than LNG, especially between 72–120 hours [1]. * **Copper T (IUCD):** The **most effective** method of emergency contraception if inserted within 5 days of unprotected intercourse. * **Mifepristone:** Can also be used as emergency contraception at low doses (10–25 mg).

Q: Which of the following is NOT an established use of estrogen?

Treatment of breast cancer. **Explanation:** The correct answer is **C (Treatment of breast cancer)**. Estrogens are generally contraindicated in breast cancer because most breast tumors are **estrogen-receptor (ER) positive** [3]. Estrogen acts as a growth factor for these malignant cells, promoting tumor progression [2]. Instead, the management of breast cancer typically involves **anti-estrogens** (like Tamoxifen) or **Aromatase Inhibitors** (like Letrozole) to block estrogenic effects [3]. **Analysis of other options:** * **A. Senile Vaginitis:** Post-menopausal estrogen deficiency leads to thinning of the vaginal epithelium (atrophic vaginitis). Topical or systemic estrogen restores the mucosal integrity and is a standard treatment. * **B. Carcinoma of the Prostate:** While not the first-line treatment today (due to the availability of GnRH analogs), high-dose estrogen (e.g., Diethylstilbestrol) was historically used to suppress LH secretion via negative feedback, thereby reducing testosterone levels which drive prostate cancer. * **D. Delayed Puberty:** In girls with primary hypogonadism (e.g., Turner Syndrome), estrogen is used to induce the development of secondary sexual characteristics and ensure proper bone maturation. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** Estrogen is the most effective treatment for **postmenopausal vasomotor symptoms** (hot flashes) [4]. * **Risk Factor:** Unopposed estrogen therapy increases the risk of **endometrial carcinoma**; therefore, progestins are always added in women with an intact uterus [1]. * **Side Effect:** Estrogens increase the risk of **thromboembolism** by increasing the synthesis of clotting factors (II, VII, IX, X) and decreasing Antithrombin III. * **Exception:** While estrogen generally promotes breast cancer, very high-dose estrogen was paradoxically used in the past for postmenopausal breast cancer, but it is **not** an established or standard use in modern practice.

Q: All of the following are anti-androgens except:

Dihydrotestosterone. **Explanation:** The correct answer is **Dihydrotestosterone (DHT)**. To answer this question, one must distinguish between an androgen (agonist) and an anti-androgen (antagonist or synthesis inhibitor). **Why Dihydrotestosterone is the correct answer:** Dihydrotestosterone is a potent, naturally occurring **androgen** (agonist). It is the active metabolite of testosterone, converted by the enzyme 5-alpha reductase. DHT has a higher affinity for androgen receptors than testosterone and is responsible for the development of male external genitalia, prostate growth, and male-pattern baldness. Since it promotes androgenic effects, it is not an anti-androgen. **Why the other options are incorrect:** * **Finasteride:** It is a **5-alpha reductase inhibitor**. By preventing the conversion of testosterone to DHT, it acts as an anti-androgen. It is primarily used for Benign Prostatic Hyperplasia (BPH) and androgenic alopecia. * **Flutamide:** It is a **pure androgen receptor antagonist**. It competes with DHT for binding sites on the target cell. It is frequently used in the management of metastatic prostatic carcinoma. * **Cyproterone acetate:** It is a **steroidal androgen receptor antagonist** that also possesses progestational activity. It inhibits the feedback loop by suppressing LH secretion and is used for treating hirsutism in females and precocious puberty. **High-Yield Clinical Pearls for NEET-PG:** * **Spironolactone:** A potassium-sparing diuretic that also acts as an androgen receptor antagonist (used in PCOS). * **Abiraterone:** A CYP17 inhibitor used in castration-resistant prostate cancer to block all androgen synthesis. * **Bicalutamide:** Preferred over Flutamide for prostate cancer due to less hepatotoxicity and once-daily dosing. * **Teratogenicity:** 5-alpha reductase inhibitors (Finasteride/Dutasteride) are contraindicated in pregnancy as they can cause feminization of a male fetus.

Q: What is a common cause of gynecomastia and infertility in men?

Cimetidine. **Explanation:** **Cimetidine**, a first-generation H2-receptor antagonist, is a classic cause of gynecomastia and infertility in men due to its unique endocrine side-effect profile. It acts through two primary mechanisms: 1. **Anti-androgenic effects:** It binds to androgen receptors and inhibits the action of dihydrotestosterone (DHT). 2. **Hyperprolactinemia:** It inhibits the metabolism of estradiol and can increase prolactin levels, especially when administered intravenously. These effects lead to an altered estrogen-to-androgen ratio, resulting in breast tissue enlargement (gynecomastia) and reduced sperm count (oligospermia/infertility). **Analysis of Incorrect Options:** * **A. Digitalis:** While chronic Digoxin use is associated with gynecomastia (due to its steroid-like structure which can mimic estrogen), it is not a primary or common cause of infertility compared to the potent anti-androgenic action of Cimetidine. * **B. Omeprazole:** As a Proton Pump Inhibitor (PPI), it is generally devoid of significant anti-androgenic or pro-estrogenic effects. * **C. Erythromycin:** This is a macrolide antibiotic. Its primary side effects are GI upset and QT prolongation; it does not affect the endocrine system or fertility. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Gynecomastia (DISCO):** **D**igoxin, **I**soniazid, **S**pironolactone, **C**imetidine, **O**estrogens. * **Cimetidine & P450:** It is a potent **enzyme inhibitor**, leading to increased levels of drugs like Warfarin, Theophylline, and Phenytoin. * **Modern H2 Blockers:** Newer agents like Ranitidine, Famotidine, and Nizatidine do **not** cause these endocrine side effects.

Q: Glucocorticoids have proved useful in the treatment of which of the following conditions?

Chemotherapy-induced vomiting. **Explanation:** **Glucocorticoids (e.g., Dexamethasone)** are highly effective in managing **chemotherapy-induced nausea and vomiting (CINV)**. While the exact mechanism is not fully understood, it is believed they act by inhibiting prostaglandin synthesis in the hypothalamus, reducing peritumoral edema, and modulating serotonin (5-HT3) receptors. Dexamethasone is often used in combination with 5-HT3 antagonists (like Ondansetron) and NK1 receptor antagonists (like Aprepitant) to enhance their antiemetic efficacy, especially in highly emetogenic chemotherapy regimens. **Analysis of Incorrect Options:** * **B. Hyperprolactinemia:** This condition is treated with **Dopamine agonists** (e.g., Cabergoline, Bromocriptine) because dopamine naturally inhibits prolactin release. Glucocorticoids have no role here. * **C. Parkinson’s Disease:** This is a neurodegenerative disorder caused by dopamine deficiency. Treatment involves increasing dopamine levels (e.g., **Levodopa-Carbidopa**) or using dopamine agonists. Glucocorticoids do not cross the blood-brain barrier to affect the basal ganglia in this manner. * **D. Type II Diabetes:** Glucocorticoids are actually **contraindicated** or must be used with extreme caution in diabetes. They promote gluconeogenesis and decrease peripheral glucose uptake, leading to **hyperglycemia** and worsening of glycemic control. **High-Yield Clinical Pearls for NEET-PG:** * **Dexamethasone** is the preferred steroid for CINV due to its high potency and minimal mineralocorticoid activity. * Glucocorticoids are also used in **Cerebral Edema** (specifically vasogenic edema associated with tumors) and **Adrenal Insufficiency** (Addison’s disease). * **Side Effects:** Chronic use leads to Cushingoid features, osteoporosis, and increased susceptibility to infections.

Q: Which of the following is an oral incretin analogue?

Semaglutide. **Explanation:** Incretin analogues, specifically **GLP-1 (Glucagon-Like Peptide-1) receptor agonists**, are agents that mimic the action of endogenous incretins to stimulate insulin secretion, inhibit glucagon release, and delay gastric emptying. **Correct Answer: A. Semaglutide** Traditionally, GLP-1 analogues were exclusively injectable due to their peptide nature, which leads to degradation by gastric acid. However, **Semaglutide** is the first and only GLP-1 analogue available in an **oral formulation**. This was achieved by co-formulating the drug with an absorption enhancer called **SNAC** (Sodium N-salcaprozate), which protects it from proteolytic degradation in the stomach and facilitates transcellular absorption. **Incorrect Options:** * **B. Dulaglutide:** A long-acting GLP-1 analogue administered as a **once-weekly subcutaneous injection**. * **C. Exenatide:** The first GLP-1 analogue (derived from Gila monster saliva). It is available as a **twice-daily or once-weekly subcutaneous injection**. * **D. Liraglutide:** A long-acting GLP-1 analogue administered as a **once-daily subcutaneous injection**. It is also FDA-approved for weight management. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Glucose-dependent insulin secretion (low risk of hypoglycemia). * **Weight Effect:** Significant **weight loss** (useful in obese Type 2 Diabetics). * **Cardiovascular Benefit:** Liraglutide, Semaglutide, and Dulaglutide reduce the risk of major adverse cardiovascular events (MACE). * **Side Effects:** Nausea/vomiting (most common) and a theoretical risk of **Medullary Thyroid Carcinoma** and **Pancreatitis**. * **Contraindication:** Personal or family history of Multiple Endocrine Neoplasia (MEN) type 2.

Question 1

A 54-year-old obese patient with type 2 diabetes mellitus and a history of alcoholism should probably not receive metformin because it can increase the risk of:

Accepted Answer

Lactic acidosis

Answer

Disulfiram-like reaction

Answer

Hypoglycemia

Answer

Severe hepatic toxicity

Question 2

Which of the following contains emergency contraception?

Accepted Answer

Levonorgestrel

Answer

Cyproterone

Answer

Desogestrel

Answer

Medroxyprogesterone

Question 3

Which of the following is NOT an established use of estrogen?

Accepted Answer

Treatment of breast cancer

Answer

Treatment of senile vaginitis

Answer

Treatment of carcinoma of the prostate

Answer

Management of delayed puberty

Question 4

All of the following are anti-androgens except:

Accepted Answer

Dihydrotestosterone

Answer

Finasteride

Answer

Flutamide

Answer

Cyproterone acetate

Question 5

Intake of which of the following medications is associated with an increased incidence of dry socket?

Accepted Answer

Oral contraceptives

Answer

Antihypertensives

Answer

Antiepileptics

Answer

Oral hypoglycemics

Question 6

What is a common cause of gynecomastia and infertility in men?

Accepted Answer

Cimetidine

Answer

Digitalis

Answer

Omeprazole

Answer

Erythromycin

Question 7

Oral contraceptives primarily act by which mechanism?

Accepted Answer

Decreasing Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH)

Answer

Increasing Luteinizing Hormone (LH)

Answer

Increasing Follicle-Stimulating Hormone (FSH)

Answer

Decreasing Adrenocorticotropic Hormone (ACTH) and Somatotropic Releasing Factor (SRF)

Question 8

Glucocorticoids have proved useful in the treatment of which of the following conditions?

Accepted Answer

Chemotherapy-induced vomiting

Answer

Hyperprolactinemia

Answer

Parkinson's disease

Answer

Type II diabetes

Question 9

Why are sulfonylureas shifted to insulin in pregnant patients?

Accepted Answer

Insulin does not cross the placenta.

Answer

Sulfonylureas cause pregnancy-induced hypertension.

Answer

Increased metabolic demands during pregnancy cannot be met by sulfonylureas alone.

Answer

Sulfonylureas deplete insulin from fetal pancreatic beta cells.

Question 10

Which of the following is an oral incretin analogue?

Accepted Answer

Semaglutide

Answer

Dulaglutide

Answer

Exenatide

Answer

Liraglutide

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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