Endocrine Pharmacology Practice Questions

Q: Magnesium is used in the treatment of which of the following conditions?

Tetany. **Explanation:** **Magnesium** acts as a physiological calcium channel blocker and plays a crucial role in neuromuscular stability. **1. Why Tetany is Correct:** Tetany is characterized by increased neuromuscular excitability. While most commonly associated with hypocalcemia, it can also be caused by **hypomagnesemia**. Magnesium is essential for the release of Parathyroid Hormone (PTH) and the responsiveness of end-organs to PTH. In cases of "refractory tetany" (where calcium levels are normal or calcium replacement fails), magnesium deficiency is the likely culprit. Administering Magnesium Sulfate ($MgSO_4$) restores ionic balance and stabilizes the neuronal membrane, effectively treating the tetany. **2. Why Other Options are Incorrect:** * **Diarrhea:** Magnesium salts (like Magnesium Citrate or Hydroxide) are **osmotic laxatives**. They cause diarrhea as a side effect or are used to treat constipation, not to treat diarrhea. * **Intractable Seizures:** While $MgSO_4$ is the drug of choice for **Eclamptic seizures**, it is not a first-line or standard treatment for general intractable seizures (Status Epilepticus), where Benzodiazepines, Phenytoin, or Levetiracetam are preferred. * **Cardiac Arrest:** Magnesium is not used in routine cardiac arrest. It is specifically indicated only if the arrest is caused by **Torsades de Pointes** (polymorphic ventricular tachycardia) or suspected hypomagnesemia. **Clinical Pearls for NEET-PG:** * **Drug of Choice:** $MgSO_4$ is the DOC for **Eclampsia** (prophylaxis and treatment) and **Torsades de Pointes**. * **Therapeutic Monitoring:** When administering $MgSO_4$, always monitor the **Patellar reflex** (first sign of toxicity is loss of reflex), respiratory rate, and urine output. * **Antidote:** The specific antidote for Magnesium toxicity is **Calcium Gluconate**.

Q: What is the standard dosage of Testosterone?

100 mg/week. **Explanation:** The standard replacement dose for testosterone in male hypogonadism aims to mimic the physiological production of testosterone in a healthy adult male, which is approximately **5–7 mg per day** (roughly 35–50 mg per week). **1. Why 100 mg/week is correct:** When using long-acting esters like **Testosterone Enanthate or Cypionate** (the most common injectable forms), the standard therapeutic dosage is **75–100 mg administered intramuscularly once a week**, or 200 mg every two weeks. This dosage typically maintains serum testosterone levels within the normal physiological range (300–1000 ng/dL) without causing excessive fluctuations or significant erythrocytosis. **2. Analysis of incorrect options:** * **150 mg/week & 200 mg/week:** While these doses are occasionally used in specific clinical scenarios, they often lead to supraphysiological peaks. Chronic administration at these levels increases the risk of side effects like polycythemia, acne, and gynecomastia (due to aromatization to estrogen). * **300 mg/week:** This is considered a **supraphysiological/performance-enhancing dose** rather than a medical replacement dose. It significantly increases the risk of cardiovascular strain and suppression of the HPT (Hypothalamic-Pituitary-Testicular) axis. **Clinical Pearls for NEET-PG:** * **Route of Administration:** Oral testosterone (undecanoate) has high first-pass metabolism; hence, injectable esters or transdermal patches/gels are preferred. * **Monitoring:** Always monitor **Hematocrit** (risk of polycythemia) and **PSA** (Prostate-Specific Antigen) before and during therapy. * **Contraindications:** Carcinoma of the prostate or breast in males is an absolute contraindication. * **Side Effects:** Cholestatic jaundice is specifically associated with **17-alpha-alkylated derivatives** (e.g., Methyltestosterone).

Q: Continuous administration of GnRH -

Suppresses the hypothalamic-pituitary axis. **Explanation:** The physiological release of Gonadotropin-Releasing Hormone (GnRH) from the hypothalamus is **pulsatile** (occurring every 90–120 minutes). This pulsatility is essential for stimulating the anterior pituitary to release LH and FSH. **Why Option B is Correct:** When GnRH is administered **continuously** (non-pulsatile), it initially causes a brief "flare" of gonadotropin release. However, this is rapidly followed by the **downregulation and desensitization** of GnRH receptors on the pituitary gonadotropes. This leads to a profound suppression of the hypothalamic-pituitary-gonadal axis, resulting in decreased levels of LH, FSH, and sex steroids (testosterone/estrogen). This pharmacological state is often referred to as "medical castration." **Why Other Options are Incorrect:** * **Option A:** Stimulation only occurs with **pulsatile** administration. Continuous exposure leads to receptor internalization and inhibition. * **Option C:** While there is a transient initial stimulation (flare), the definitive and therapeutic effect of continuous administration is always suppression. * **Option D:** GnRH is a potent regulator of the axis; it never has "no effect." **NEET-PG High-Yield Pearls:** * **GnRH Agonists:** Leuprolide, Goserelin, Nafarelin, Buserelin. * **Clinical Uses of Continuous GnRH:** Prostate cancer, endometriosis, precocious puberty, and uterine fibroids. * **The "Flare" Phenomenon:** In prostate cancer, the initial surge in testosterone can worsen bone pain. This is prevented by co-administering an androgen receptor blocker (e.g., Flutamide) during the first few weeks of therapy. * **GnRH Antagonists:** (e.g., Cetrorelix, Ganirelix) suppress the axis immediately without the initial flare.

Q: What is a common side effect of clomiphene citrate?

All of the above. **Explanation:** Clomiphene citrate is a **Selective Estrogen Receptor Modulator (SERM)** and the first-line treatment for ovulatory dysfunction in PCOS. It acts as a competitive antagonist at estrogen receptors in the hypothalamus. By blocking the negative feedback of endogenous estrogen, it leads to an increase in GnRH pulse frequency, subsequently increasing FSH and LH levels to stimulate follicular development. **Why "All of the above" is correct:** * **Hot flushes (Option B):** This is the **most common** side effect (occurring in ~10% of patients). It occurs because clomiphene blocks estrogen receptors in the hypothalamus, mimicking a "hypoestrogenic" state similar to menopause. * **Ovarian Hyperstimulation Syndrome (OHSS) (Option C):** While less common with clomiphene than with gonadotropins, it can still occur due to the stimulation of multiple follicles. It can also lead to **multiple pregnancies** (mostly twins). * **Alopecia (Option A):** Reversible hair thinning is a documented, though less frequent, side effect of clomiphene therapy. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Antagonist at the hypothalamus (blocks negative feedback) but acts as a partial agonist in the ovaries. * **Visual Disturbances:** A high-yield side effect; patients may report blurring or "scintillating scotoma." If these occur, the drug should be discontinued. * **Anti-estrogenic effects:** It can cause thinning of the endometrium and thickening of cervical mucus, which may paradoxically hinder conception despite successful ovulation. * **Risk of Multiple Gestation:** Approximately 5–10% (primarily twins).

Q: All of the following drugs cause osteoporosis except?

Alendronate. **Explanation:** The correct answer is **Alendronate** because it is a **Bisphosphonate**, which is a drug used to **treat** osteoporosis, not cause it. **1. Why Alendronate is correct:** Alendronate inhibits osteoclast-mediated bone resorption. It binds to hydroxyapatite crystals in the bone and, when taken up by osteoclasts, inhibits the enzyme **farnesyl pyrophosphate synthase**. This leads to osteoclast apoptosis, thereby increasing bone mineral density (BMD) and reducing fracture risk. **2. Why the other options are incorrect:** * **Steroids (Glucocorticoids):** These are the most common cause of drug-induced osteoporosis. They decrease osteoblast activity, increase osteoclast survival, and decrease intestinal calcium absorption. * **Thyroxine:** Excess thyroid hormone (as in hyperthyroidism or over-replacement therapy) increases bone turnover with a net shift toward resorption, leading to secondary osteoporosis. * **Heparin:** Long-term use of unfractionated heparin (UFH) stimulates osteoclasts and inhibits osteoblasts, leading to decreased bone density. (Note: LMWH has a lower risk than UFH). **High-Yield Clinical Pearls for NEET-PG:** * **Other drugs causing osteoporosis:** Phenytoin, Phenobarbital (via Vitamin D metabolism), GnRH agonists, Aromatase inhibitors, and Proton Pump Inhibitors (PPIs). * **Alendronate Administration:** 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**. * **Rare side effect of Bisphosphonates:** Osteonecrosis of the Jaw (ONJ) and atypical subtrochanteric fractures.

Q: Based on the given mechanism of action as shown in the Figure, Drug A is likely to be:

Vildagliptin. ***Vildagliptin*** - **DPP-4 inhibitor** that prevents degradation of endogenous **GLP-1** and **GIP**, increasing their activity to enhance glucose-dependent insulin secretion and suppress glucagon release. - Works by blocking the **dipeptidyl peptidase-4 enzyme**, allowing incretin hormones to remain active longer and improve glycemic control without significant hypoglycemia risk. *Exenatide* - A **GLP-1 receptor agonist** that directly activates GLP-1 receptors, rather than inhibiting DPP-4 enzyme activity. - Administered via **subcutaneous injection** and has additional effects like **gastric emptying delay** and **weight loss**, unlike DPP-4 inhibitors. *Canagliflozin* - An **SGLT-2 inhibitor** that works in the **proximal renal tubules** to block glucose reabsorption, promoting glucosuria. - Mechanism involves **sodium-glucose cotransporter-2 inhibition** in kidneys, completely different from incretin pathway modulation. *Pramlintide* - An **amylin analogue** that mimics the action of **pancreatic amylin hormone**, slowing gastric emptying and suppressing glucagon. - Works through **amylin receptors** in the brain and gastrointestinal tract, not through incretin hormone pathways or DPP-4 inhibition.

Q: Danazol is used in all of the following conditions except:

Pituitary adenoma. **Explanation:** **Danazol** is a synthetic ethisterone derivative that acts as a **weak androgen** and a **mixed agonist/antagonist** of steroid receptors. Its primary mechanism involves inhibiting the mid-cycle surge of LH and FSH by suppressing the hypothalamic-pituitary-ovarian axis, leading to a state of "pseudomenopause." **Why Pituitary Adenoma is the Correct Answer:** Danazol is **not** used to treat pituitary adenomas [1]. In fact, because Danazol suppresses the feedback loop, it is contraindicated in patients with undiagnosed abnormal uterine bleeding or significant pituitary dysfunction. Pituitary adenomas (like prolactinomas or GH-secreting tumors) are typically managed with dopamine agonists (Cabergoline), somatostatin analogs (Octreotide), or surgery. **Analysis of Incorrect Options:** * **Endometriosis:** This is the primary clinical indication for Danazol [1]. It causes atrophy of ectopic endometrial tissue by creating a hypoestrogenic, hyperandrogenic environment. * **Fibroadenosis (Fibrocystic Breast Disease):** Danazol reduces breast pain and nodularity by suppressing the hormonal fluctuations that stimulate breast tissue [1]. * **Dysfunctional Uterine Bleeding (DUB):** By inducing endometrial atrophy and inhibiting ovulation, Danazol effectively reduces menstrual blood loss. **High-Yield Clinical Pearls for NEET-PG:** * **Other Indications:** Hereditary Angioedema [1] (increases synthesis of C1 esterase inhibitor) and ITP. * **Side Effects:** Significant androgenic effects (weight gain [1], acne, hirsutism, deepening of voice) and hepatotoxicity [2]. * **Contraindication:** Pregnancy (risk of virilization of female fetus) [2]. * **Mechanism Summary:** "4-I's" — **I**nhibits steroidogenic enzymes, **I**nhibits gonadotropin release, **I**ncreases free testosterone (displaces from SHBG), and **I**nduces endometrial atrophy.

Q: An elderly male has benign prostatic hyperplasia. Which of the following medications can be used to suppress prostatic growth?

Finasteride. **Explanation:** **Finasteride** is the correct answer because it is a selective **5-alpha reductase inhibitor**. In the prostate, the enzyme 5-alpha reductase converts testosterone into **Dihydrotestosterone (DHT)**, which is the potent androgen responsible for prostatic cell proliferation. By inhibiting this enzyme, Finasteride reduces intraprostatic DHT levels, leading to a reduction in prostate volume (shrinkage) over 6–12 months. This makes it a disease-modifying drug for Benign Prostatic Hyperplasia (BPH). **Analysis of Incorrect Options:** * **Spironolactone (A):** A potassium-sparing diuretic that also acts as an aldosterone antagonist and weak androgen receptor blocker. While it has anti-androgenic side effects (like gynecomastia), it is not a standard treatment for suppressing prostatic growth in BPH. * **Ketoconazole (B):** An antifungal that inhibits steroid synthesis (including testosterone) at high doses. Due to its significant toxicity (hepatotoxicity and adrenal suppression), it is not used for BPH. * **Flutamide (D):** A pure non-steroidal anti-androgen that blocks androgen receptors. It is primarily used in the management of **Prostate Cancer**, not BPH, due to its side effect profile and the fact that it does not effectively reduce prostate size in non-malignant conditions compared to 5-alpha reductase inhibitors. **NEET-PG High-Yield Pearls:** * **Finasteride vs. Dutasteride:** Finasteride inhibits Type II 5-alpha reductase; Dutasteride inhibits both Type I and Type II. * **Clinical Use:** Finasteride is also used for **Male Pattern Baldness** (Androgenetic Alopecia). * **Dynamic vs. Static:** Alpha-blockers (e.g., Tamsulosin) treat the *dynamic* component (smooth muscle tone), while Finasteride treats the *static* component (size). * **Side Effects:** Decreased libido and erectile dysfunction are common. It also decreases serum PSA levels by approximately 50%.

Q: Gestrinone has the following actions except?

Anti-androgenic. **Explanation:** Gestrinone is a synthetic steroid derivative of 19-nortestosterone primarily used in the treatment of endometriosis. To understand its mechanism, it is essential to recognize its **mixed agonist-antagonist profile** on various steroid receptors. **Why "Anti-androgenic" is the correct answer:** Gestrinone possesses significant **androgenic** activity rather than anti-androgenic activity. It binds to androgen receptors and exerts agonist effects, which contributes to its side effect profile (e.g., weight gain, acne, and hirsutism). Therefore, stating it is "anti-androgenic" is pharmacologically incorrect. **Analysis of other options:** * **Androgenic (A):** As a 19-nortestosterone derivative, it has inherent weak androgenic properties. * **Anti-oestrogenic (B):** It acts centrally to suppress the mid-cycle surge of LH and FSH, leading to decreased ovarian estrogen production. It also has direct antagonistic effects at the endometrial level. * **Anti-progestogenic (D):** Gestrinone acts as a selective progesterone receptor modulator (SPRM) with predominant **antagonist** activity on the endometrium, leading to atrophy of ectopic endometrial tissue. **Clinical Pearls for NEET-PG:** * **Primary Indication:** Second-line treatment for **Endometriosis** (similar efficacy to Danazol but with a longer half-life, allowing twice-weekly dosing). * **Mechanism Summary:** It creates a "high-androgen, low-estrogen" environment that induces atrophy of the endometrium. * **Contraindications:** Pregnancy (due to virilization of a female fetus) and severe hepatic/renal impairment. * **Key Side Effects:** Acne, oily skin, hirsutism, and voice changes (due to its androgenic nature).

Q: All of the following are effects of estrogen, EXCEPT:

Increased protein C and S levels. **Explanation:** The correct answer is **D (Increased protein C and S levels)** because estrogen actually **decreases** the levels of Protein C and Protein S (natural anticoagulants) and increases the levels of clotting factors (II, VII, IX, and X). This shift creates a **pro-thrombotic state**, increasing the risk of deep vein thrombosis (DVT) and pulmonary embolism. **Analysis of Options:** * **A. Beneficial effect on cognition:** Estrogen has neuroprotective properties. It enhances synaptic plasticity and cerebral blood flow, which is why postmenopausal estrogen deficiency is often linked to "brain fog" or cognitive decline. * **B & C. Effects on Bone (Osteoclasts/Osteoblastic activity):** Estrogen is vital for bone health. It **reduces osteoclastic activity** (by inducing apoptosis of osteoclasts and inhibiting RANKL) and **increases osteoblastic activity** (by stimulating TGF-β). This dual action prevents bone resorption and maintains bone mineral density. **NEET-PG High-Yield Pearls:** * **Lipid Profile:** Estrogen increases HDL ("good" cholesterol) and decreases LDL, but it also **increases Triglycerides**. * **Biliary System:** It increases cholesterol secretion in bile, leading to a higher risk of **gallstones** (cholelithiasis). * **Cancer Risk:** Unopposed estrogen increases the risk of **endometrial carcinoma**; hence, it is always combined with progestins in women with an intact uterus. * **Metabolism:** Estrogen increases the synthesis of transport proteins in the liver, such as Sex Hormone Binding Globulin (SHBG) and Thyroid Binding Globulin (TBG).

Question 1

Magnesium is used in the treatment of which of the following conditions?

Accepted Answer

Tetany

Answer

Diarrhea

Answer

Intractable seizures

Answer

Cardiac arrest

Question 2

What is the standard dosage of Testosterone?

Accepted Answer

100 mg/week

Answer

300 mg/week

Answer

200 mg/week

Answer

150 mg/week

Question 3

Continuous administration of GnRH -

Accepted Answer

Suppresses the hypothalamic-pituitary axis

Answer

Stimulates the hypothalamic-pituitary axis

Answer

May suppress or stimulate the hypothalamic-pituitary axis

Answer

Has no effect on the hypothalamic-pituitary axis

Question 4

What is a common side effect of clomiphene citrate?

Accepted Answer

All of the above

Answer

Alopecia

Answer

Hot flushes

Answer

Ovarian hyperstimulation syndrome

Question 5

All of the following drugs cause osteoporosis except?

Accepted Answer

Alendronate

Answer

Steroid

Answer

Thyroxine

Answer

Heparin

Question 6

Based on the given mechanism of action as shown in the Figure, Drug A is likely to be:

Accepted Answer

Vildagliptin

Answer

Exenatide

Answer

Canagliflozin

Answer

Pramlintide

Question 7

Danazol is used in all of the following conditions except:

Accepted Answer

Pituitary adenoma

Answer

Fibroadenosis of breast

Answer

Dysfunctional uterine bleeding

Answer

Endometriosis

Question 8

An elderly male has benign prostatic hyperplasia. Which of the following medications can be used to suppress prostatic growth?

Accepted Answer

Finasteride

Answer

Spironolactone

Answer

Ketoconazole

Answer

Flutamide

Question 9

Gestrinone has the following actions except?

Accepted Answer

Anti-androgenic

Answer

Androgenic

Answer

Anti-oestrogenic

Answer

Anti-progestogenic

Question 10

All of the following are effects of estrogen, EXCEPT:

Accepted Answer

Increased protein C and S levels

Answer

Beneficial effect on cognition

Answer

Reduced osteoclastic activity

Answer

Increased osteoblastic activity

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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