Which of the following is a synthetic estrogen?
Which medication is commonly used in heart failure that also has aldosterone antagonistic properties?
Which of the following drugs acts directly to induce an erection without the need for sexual stimulation?
Guanethidine is used in the treatment of which of the following conditions?
Which of the following best describes a Type B adverse drug reaction?
Which of the following statements about dopamine is false?
Which of the following is a centrally acting antihypertensive drug?
Which of the following statements about Conivaptan is correct?
Which of the following potassium-sparing diuretics was the first to be shown to reduce cardiac mortality in chronic heart failure patients?
Long-term steroid ingestion leads to all of the following except:
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 31: Which of the following is a synthetic estrogen?
- A. Estrone
- B. Estriol
- C. Estradiol
- D. Diethylstilbestrol (Correct Answer)
Explanation: ***Diethylstilbestrol*** - **Diethylstilbestrol (DES)** is a **synthetic non-steroidal estrogen** that was historically used as a medication, particularly to prevent miscarriage. - Its use was discontinued after being linked to various adverse effects, including **vaginal clear cell adenocarcinoma** in female offspring whose mothers took DES during pregnancy. *Estrone* - **Estrone** is one of the three major **naturally occurring endogenous estrogens** in humans. - It is the primary estrogen during **menopause** and is derived from androstenedione. *Estriol* - **Estriol** is another of the three major **naturally occurring estrogens**, predominantly produced during **pregnancy** by the placenta. - It is often used as a marker for fetal well-being. *Estradiol* - **Estradiol** is the **most potent and abundant naturally occurring estrogen** in women during their reproductive years. - It plays a crucial role in the development and maintenance of female reproductive tissues and secondary sexual characteristics.
Question 32: Which medication is commonly used in heart failure that also has aldosterone antagonistic properties?
- A. Carvedilol
- B. Spironolactone (Correct Answer)
- C. Abiraterone
- D. Sacubitril/Valsartan
Explanation: ***Spironolactone*** - **Spironolactone** is a **potassium-sparing diuretic** that acts as a **competitive antagonist of aldosterone** receptors, primarily in the collecting ducts of the kidneys. - This action leads to increased excretion of sodium and water, and retention of potassium, which is beneficial in **heart failure** by reducing fluid overload and mitigating the detrimental effects of aldosterone on cardiac remodeling. *Carvedilol* - **Carvedilol** is a **beta-blocker** with additional **alpha-1 blocking** properties, commonly used in heart failure to reduce heart rate, blood pressure, and myocardial oxygen demand. - It does not possess significant aldosterone antagonistic properties. *Sacubitril/Valsartan* - **Sacubitril/Valsartan** is an **angiotensin receptor-neprilysin inhibitor (ARNI)**. Valsartan is an **angiotensin receptor blocker (ARB)**, and sacubitril inhibits neprilysin, an enzyme that degrades natriuretic peptides. - While it modulates the **renin-angiotensin-aldosterone system (RAAS)** and is highly effective in heart failure, it does not directly antagonize aldosterone receptors. *Abiraterone* - **Abiraterone** is an **androgen-biosynthesis inhibitor** used in the treatment of **prostate cancer**. - Its primary mechanism involves inhibiting **CYP17**, an enzyme critical for androgen production, and it has no role in the management of heart failure or aldosterone antagonism.
Question 33: Which of the following drugs acts directly to induce an erection without the need for sexual stimulation?
- A. Sildenafil
- B. Tadalafil
- C. Alprostadil (Correct Answer)
- D. Testosterone
Explanation: ***Alprostadil***- **Alprostadil** is a **prostaglandin E1** analog that can directly induce vasodilation in the penile arteries, leading to an erection without sexual stimulation [1].- It is typically administered via **intracavernosal injection** or as a **urethral suppository**.*Sildenafil*- **Sildenafil** is a **PDE5 inhibitor** that works by enhancing the effects of **nitric oxide**, which is released in response to sexual stimulation [2, 3].- It requires **sexual arousal** to be effective, as it doesn't directly initiate the erectile process [2, 3].*Tadalafil*- Similar to sildenafil, **tadalafil** is also a **PDE5 inhibitor** that works by increasing cGMP levels and promoting smooth muscle relaxation [2, 3].- Its action is dependent on the release of **nitric oxide** triggered by sexual stimulation [2, 3].*Testosterone*- **Testosterone** is a hormone involved in sex drive and overall erectile function over time, but it does not directly or acutely induce an erection.- Its primary role in erectile dysfunction is in cases of **hypogonadism**, and it requires sexual stimulation for its effects on erection.
Question 34: Guanethidine is used in the treatment of which of the following conditions?
- A. Ptosis
- B. Bell's palsy
- C. Thyrotoxic ophthalmopathy (Correct Answer)
- D. Horner's syndrome
Explanation: ***Thyrotoxic ophthalmopathy*** - Guanethidine is an **adrenergic neuron blocker** that can be used topically to reduce the sympathetic overactivity in the eye associated with thyrotoxicosis. - It helps alleviate symptoms like **retraction of the eyelids** and proptosis by blocking norepinephrine release from sympathetic nerve endings. *Ptosis* - **Ptosis** is primarily caused by weakness of the levator palpebrae superioris muscle or oculomotor nerve dysfunction, not sympathetic overactivity. - Guanethidine would not address the underlying muscular or neurologic deficit causing ptosis. *Bell's palsy* - **Bell's palsy** involves sudden, temporary weakness or paralysis of the muscles on one side of the face due to a dysfunction of the facial nerve. - Treatment typically involves corticosteroids and antivirals; guanethidine has no role in its management. *Horner's syndrome* - **Horner's syndrome** is characterized by miosis, ptosis, and anhidrosis, resulting from damage to the sympathetic nerve supply to the eye and face. - Guanethidine's mechanism of action would exacerbate, rather than treat, the existing sympathetic deficit in Horner's syndrome.
Question 35: Which of the following best describes a Type B adverse drug reaction?
- A. Augmented effect of drug
- B. Effect seen on chronic use of drug
- C. Delayed effect of drug
- D. Unpredictable bizarre reaction (Correct Answer)
Explanation: ***Unpredictable bizarre reaction*** - Type B reactions are **unpredictable**, **bizarre**, and not directly related to the drug's known pharmacological actions. - They often involve **immunological reactions** or genetic predispositions, such as allergies or idiosyncratic responses. *Augmented effect of drug* - This describes a **Type A** adverse drug reaction, which is predictable and results from an **exaggerated pharmacological effect** of the drug. - It is typically dose-dependent and can be managed by adjusting the dosage. *Effect seen on chronic use of drug* - This description can apply to several types of adverse reactions, but it commonly relates to **Type C (chronic) reactions**, where effects occur only after prolonged exposure. - These reactions might be due to **cumulative toxicity** or adaptive changes in the body. *Delayed effect of drug* - This aligns with **Type D (delayed) adverse drug reactions**, which manifest long after the drug exposure has ended or after a period of latency. - Examples include **carcinogenesis** or teratogenesis, occurring months or years later.
Question 36: Which of the following statements about dopamine is false?
- A. Improves renal perfusion
- B. Causes Vasoconstriction
- C. Causes increase in GI Ischemia (Correct Answer)
- D. Positive ionotropic
Explanation: ***Causes increase in GI Ischemia*** (FALSE Statement) - This statement is **incorrect and misleading** as dopamine does not primarily "cause increase in GI ischemia" - While dopamine at **higher doses** can cause **splanchnic vasoconstriction** via alpha-1 receptors, this is not characterized as "causing GI ischemia" in standard pharmacology - GI ischemia is a potential adverse effect in susceptible patients, but not a primary pharmacological effect or standard clinical description of dopamine *Positive inotropic* (TRUE Statement) - Dopamine is a **catecholamine** with dose-dependent effects; at **moderate doses (5-10 mcg/kg/min)**, it stimulates **beta-1 adrenergic receptors** in the heart - This beta-1 stimulation leads to increased **myocardial contractility** and **heart rate**, thus exerting a **positive inotropic effect** - This is a well-established therapeutic effect of dopamine *Improves renal perfusion* (TRUE Statement) - At **low doses (0.5-3 mcg/kg/min)**, dopamine selectively activates **dopamine-1 (D1) receptors** in the renal vasculature - This activation causes **renal vasodilation**, leading to increased **renal blood flow**, improved **glomerular filtration rate**, and enhanced **sodium excretion** - This "renal dose" effect is a classic pharmacological property of dopamine *Causes Vasoconstriction* (TRUE Statement) - At **high doses (>10 mcg/kg/min)**, dopamine primarily stimulates **alpha-1 adrenergic receptors** - This leads to generalized **vasoconstriction**, increasing **systemic vascular resistance** and **blood pressure** - This dose-dependent alpha effect is well-documented
Question 37: Which of the following is a centrally acting antihypertensive drug?
- A. Phenoxybenzamine
- B. Propranolol
- C. Prazosin
- D. Methyldopa (Correct Answer)
Explanation: ***Methyldopa*** - **Methyldopa** is a **prodrug** that is converted to **alpha-methylnorepinephrine** in the brain, which then stimulates **alpha-2 adrenergic receptors** in the brainstem. - This stimulation reduces **sympathetic outflow** from the central nervous system, leading to decreased heart rate, stroke volume, and peripheral vascular resistance, thus lowering blood pressure. *Phenoxybenzamine* - **Phenoxybenzamine** is an **alpha-1 and alpha-2 adrenergic receptor antagonist** (non-selective alpha blocker) that primarily acts peripherally. - It causes **vasodilation** by blocking alpha-1 receptors on smooth muscle, which reduces peripheral vascular resistance. *Propranolol* - **Propranolol** is a **non-selective beta-blocker** that primarily acts on peripheral beta-adrenergic receptors. - It reduces heart rate and cardiac output by blocking **beta-1 receptors** in the heart and can also affect beta-2 receptors in the lungs and vasculature. *Prazosin* - **Prazosin** is a **selective alpha-1 adrenergic receptor antagonist** that acts primarily on peripheral blood vessels. - It causes **vasodilation** in both arteries and veins by blocking alpha-1 receptors, which reduces both preload and afterload, lowering blood pressure.
Question 38: Which of the following statements about Conivaptan is correct?
- A. It is a vasopressin antagonist. (Correct Answer)
- B. It selectively acts on V2 receptors.
- C. It is administered orally.
- D. All of the options.
Explanation: ***It is a vasopressin antagonist.*** * **Conivaptan** is a non-peptide, dual **vasopressin V1A and V2 receptor antagonist**, meaning it blocks the action of vasopressin. * By blocking vasopressin, it promotes **aquaresis** (excretion of solute-free water), which is beneficial in conditions like **hyponatremia**. * *It selectively acts on V2 receptors.* * **Conivaptan** is a **dual antagonist**, blocking both **V1A and V2 receptors**, not just V2. * **Tolvaptan**, in contrast, is a selective **V2 receptor antagonist**. * *It is administered orally.* * **Conivaptan** is typically administered intravenously, particularly in hospital settings for acute hyponatremia. * **Tolvaptan** is the orally administered vasopressin antagonist. * *All of the options.* * Since Conivaptan is not selectively acting on V2 receptors and is not administered orally, this option is incorrect.
Question 39: Which of the following potassium-sparing diuretics was the first to be shown to reduce cardiac mortality in chronic heart failure patients?
- A. Spironolactone (Correct Answer)
- B. Amiloride
- C. Triamterene
- D. Eplerenone
Explanation: ***Spironolactone*** - **Spironolactone** was the first potassium-sparing diuretic shown to reduce **cardiac mortality** in patients with **chronic heart failure** in the **RALES trial** (Randomized Aldactone Evaluation Study). - Its beneficial effects in heart failure are primarily attributed to its **aldosterone receptor antagonist** properties, which counteract the harmful effects of aldosterone on the myocardium and vasculature, rather than just its diuretic effect. *Amiloride* - **Amiloride** is a potassium-sparing diuretic that works by directly inhibiting **epithelial sodium channels (ENaC)** in the collecting duct. - While it helps in potassium conservation, it has not been shown to significantly reduce cardiac mortality in chronic heart failure patients in clinical trials. *Triamterene* - **Triamterene** is another potassium-sparing diuretic that also directly inhibits **ENaC** in the collecting duct, similar to amiloride. - Like amiloride, it is used to prevent hypokalemia but lacks evidence for significant **cardiac mortality reduction** in chronic heart failure. *Eplerenone* - **Eplerenone** is a selective **aldosterone receptor antagonist**, similar to spironolactone, with fewer hormonal side effects. - While it has been shown to reduce **cardiac mortality** in chronic heart failure (e.g., in the EMPHASIS-HF trial), it was introduced later than spironolactone and was not the *first* to demonstrate this benefit.
Question 40: Long-term steroid ingestion leads to all of the following except:
- A. Avascular necrosis of head of femur
- B. Growth retardation
- C. Hypoglycemia (Correct Answer)
- D. Cataract
Explanation: ***Hypoglycemia*** - Chronic steroid use primarily leads to **hyperglycemia** due to increased **gluconeogenesis** and **insulin resistance**, not hypoglycemia. - Steroids raise blood glucose levels, potentially inducing or worsening **diabetes mellitus**. *Avascular necrosis of head of femur* - Long-term steroid use is a well-established risk factor for **avascular necrosis**, particularly affecting the **femoral head**. - This occurs due to impaired blood supply to the bone, leading to its death. *Cataract* - **Posterior subcapsular cataracts** are a known ocular complication of prolonged systemic corticosteroid therapy. - The mechanism involves direct effects of steroids on lens metabolism and protein aggregation. *Growth retardation* - In children, chronic corticosteroid therapy can suppress growth, leading to **growth retardation**. - This is due to interference with **growth hormone secretion** and direct effects on bone formation.