Cardiovascular Drugs Practice Questions

Q: A drug is a classical example of pharmacological success but therapeutic failure due to the coronary steal phenomenon. Which drug is it?

Dipyridamole. ### Explanation **Correct Option: B. Dipyridamole** **The Concept: Coronary Steal Phenomenon** Dipyridamole is a potent coronary vasodilator that acts by inhibiting adenosine deaminase and phosphodiesterase, leading to increased adenosine levels. While it is a "pharmacological success" because it effectively dilates coronary arteries, it is a "therapeutic failure" in treating angina due to the **Coronary Steal Phenomenon**. In a patient with coronary artery disease, vessels supplying ischemic areas are already maximally dilated by local metabolites. When dipyridamole is administered, it dilates the healthy, non-ischemic vessels. This reduces resistance in the healthy zones, "stealing" blood flow away from the stenosed, ischemic areas and diverting it to well-perfused areas, potentially worsening the ischemia. **Why other options are incorrect:** * **A. Glyceryl trinitrate (GTN):** GTN primarily causes venodilation (reducing preload) and dilates large epicardial coronary arteries without causing steal. It is the drug of choice for acute angina. * **C. Propranolol:** A beta-blocker that reduces myocardial oxygen demand by decreasing heart rate and contractility. It does not cause vasodilation or coronary steal. * **D. Diltiazem:** A calcium channel blocker that reduces heart rate and causes coronary vasodilation, but it does not typically induce the steal phenomenon to a clinically significant degree compared to dipyridamole. **High-Yield NEET-PG Pearls:** * **Clinical Use:** Because of its ability to induce "steal," Dipyridamole is used in **Thallium/Persantine Stress Testing** to identify ischemic areas in patients unable to exercise. * **Antiplatelet Action:** Dipyridamole is also used in combination with Aspirin for secondary stroke prevention. * **Other "Steal" drugs:** Hydralazine and Isoflurane are also associated with coronary steal.

Q: A patient with cardiac disease should be advised to stop which of the following medications if experiencing a persistent cough?

Enalapril. **Explanation:** **Correct Option: C. Enalapril** Enalapril is an **ACE (Angiotensin-Converting Enzyme) inhibitor**. The most characteristic side effect of ACE inhibitors is a **dry, persistent, non-productive cough**, occurring in approximately 5–20% of patients. * **Mechanism:** ACE is identical to Kininase II, the enzyme responsible for breaking down **Bradykinin** and **Substance P**. By inhibiting this enzyme, ACE inhibitors lead to an accumulation of these pro-inflammatory autacoids in the lungs. This irritates the sensory afferent C-fibers in the airways, triggering the cough reflex. * **Clinical Action:** If a patient develops this cough, the medication should be discontinued and replaced with an **ARB (Angiotensin Receptor Blocker)** like Losartan, which does not interfere with bradykinin metabolism. **Incorrect Options:** * **A. Diltiazem:** A non-dihydropyridine calcium channel blocker (CCB). Common side effects include bradycardia, constipation, and peripheral edema, but not cough. * **B. Aspirin:** An antiplatelet agent. While it can trigger "Aspirin-Exacerbated Respiratory Disease" (bronchospasm/asthma) in sensitive individuals, it does not typically cause a persistent dry cough. * **D. Clopidogrel:** A P2Y12 receptor antagonist. Its primary side effects are bleeding and gastrointestinal upset; it has no association with a cough. **High-Yield Clinical Pearls for NEET-PG:** * **ACEi Side Effects (Mnemonic: CAPTOPRIL):** **C**ough, **A**ngioedema, **P**roteinuria/Potassium excess (Hyperkalemia), **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis contraindication, **I**ncreased renin, **L**eukopenia. * The cough usually starts within 1 week to 6 months of therapy and typically resolves within 1–4 weeks after stopping the drug. * **Switching:** ARBs are the best alternative for patients who develop an ACEi-induced cough.

Q: Which of the following antiarrhythmic drugs does not cause Torsades de Pointes?

Lidocaine. **Explanation:** The risk of **Torsades de Pointes (TdP)** is directly linked to the prolongation of the **QT interval**. This occurs when a drug inhibits the outward potassium current ($I_K$), thereby delaying ventricular repolarization. **Why Lidocaine is the Correct Answer:** Lidocaine is a **Class IB antiarrhythmic**. Unlike other sodium channel blockers, Class IB drugs preferentially bind to sodium channels in the inactivated state and have a very rapid dissociation rate. Most importantly, Lidocaine **shortens the action potential duration (APD)** and the QT interval. Because it does not prolong repolarization, it carries a negligible risk of inducing Torsades de Pointes. **Why the Other Options are Incorrect:** * **Quinidine, Disopyramide, and Procainamide** are all **Class IA antiarrhythmics**. * The hallmark of Class IA drugs is that they block both fast sodium channels and **potassium channels**. * By blocking potassium channels, they significantly prolong the action potential duration and the **QT interval**. A prolonged QT interval creates a window of vulnerability for "early after-depolarizations" (EADs), which can trigger the polymorphic ventricular tachycardia known as Torsades de Pointes. **NEET-PG High-Yield Pearls:** * **Mnemonic for Class IA (QT prolongers):** "**Q**ueen **P**rom **D**isco" (**Q**uinidine, **P**rocainamide, **D**isopyramide). * **Class III drugs** (e.g., Sotalol, Ibutilide, Dofetilide) are also notorious for causing TdP due to potent potassium channel blockade. **Amiodarone** is a unique Class III drug that prolongs the QT interval but rarely causes TdP. * **Treatment of choice for TdP:** Intravenous **Magnesium Sulfate**, even if serum magnesium levels are normal.

Q: Which of the following is a venodilator?

Nitroprusside. ### Explanation **Sodium Nitroprusside** is the correct answer because it is a **balanced vasodilator**, meaning it acts on both the arterial (resistance) and venous (capacitance) vessels. **Mechanism of Action:** Nitroprusside acts by releasing **Nitric Oxide (NO)**, which stimulates guanylyl cyclase to increase intracellular **cGMP**. This leads to dephosphorylation of myosin light chains and relaxation of smooth muscles in both arterioles and venules. By dilating veins, it increases venous capacitance, thereby reducing **preload** (venous return to the heart). **Analysis of Incorrect Options:** * **A. Hydralazine:** This is a selective **arteriolar dilator**. It has minimal to no effect on the venous system. It is commonly used in pregnancy-induced hypertension. * **B. Minoxidil:** A potent **arteriolar dilator** that works by opening ATP-sensitive $K^+$ channels, causing hyperpolarization of smooth muscle. It is associated with reflex tachycardia and hypertrichosis. * **C. Nifedipine:** A Dihydropyridine **Calcium Channel Blocker (CCB)** that acts predominantly on the L-type calcium channels in the **arterial** smooth muscle. It does not possess significant venodilating properties. **High-Yield Clinical Pearls for NEET-PG:** * **Preload vs. Afterload:** Pure venodilators (like Nitroglycerin at low doses) reduce preload; pure arteriolar dilators (like Hydralazine) reduce afterload. Nitroprusside reduces **both**. * **Toxicity:** Prolonged infusion of Nitroprusside can lead to **Cyanide and Thiocyanate toxicity**. The antidote is Sodium Thiosulfate or Hydroxocobalamin. * **Light Sensitivity:** Nitroprusside is unstable in light; hence, the infusion bottle must be covered with opaque foil. * **Drug of Choice:** It was traditionally the drug of choice for **Hypertensive Emergencies**, though it is now often replaced by Labetalol or Nicardipine due to its toxicity profile.

Q: Which of the following drugs can cause glucose intolerance?

All of the above. **Explanation:** The correct answer is **D. All of the above**. Several classes of cardiovascular drugs can interfere with glucose metabolism, leading to hyperglycemia or "new-onset diabetes." 1. **Thiazides (e.g., Chlorthalidone, Hydrochlorothiazide):** These are the most common culprits. They cause glucose intolerance primarily through **hypokalemia**. Low extracellular potassium inhibits the release of insulin from pancreatic beta cells (as insulin secretion is a potassium-dependent process). They also decrease peripheral insulin sensitivity. 2. **Propranolol (Non-selective Beta-blockers):** Beta-blockers interfere with carbohydrate metabolism by inhibiting $\beta_2$-mediated insulin release and reducing peripheral glucose uptake. Furthermore, they mask the autonomic warning symptoms of hypoglycemia (like tachycardia and tremors), making them risky for diabetic patients. 3. **Furosemide (Loop Diuretics):** Similar to thiazides, loop diuretics can cause hyperglycemia, though generally to a lesser extent. The mechanism is again linked to hypokalemia-induced inhibition of insulin secretion. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice for HTN in Diabetics:** ACE inhibitors or ARBs (they are Reno-protective and metabolic-neutral). * **Metabolic Side Effects of Thiazides:** Remember the mnemonic **"Hyper-GLUC"** (Hyper**G**lycemia, Hyper**L**ipidemia, Hyper**U**ricemia, Hyper**C**alcemia). * **Beta-blocker exception:** Vasodilatory beta-blockers like **Carvedilol** and **Nebivolol** have a neutral or even beneficial effect on glycemic control compared to Propranolol. * **Potassium Link:** Maintaining normal serum potassium levels can often reverse or mitigate diuretic-induced glucose intolerance.

Q: Which one of the following is not an adverse effect of ACE inhibitors?

Hypokalemia. **Explanation:** **Why Hypokalemia is the Correct Answer:** ACE inhibitors (ACEIs) block the conversion of Angiotensin I to Angiotensin II. Since Angiotensin II is a potent stimulator of **aldosterone** secretion from the adrenal cortex, its inhibition leads to decreased aldosterone levels. Aldosterone normally promotes sodium reabsorption and potassium excretion in the distal tubule; therefore, ACEIs cause potassium retention, leading to **Hyperkalemia**, not hypokalemia. This is a critical side effect, especially in patients with chronic kidney disease or those taking potassium-sparing diuretics. **Analysis of Incorrect Options:** * **A. Cough:** This is the most common side effect (approx. 10%). ACEIs prevent the breakdown of **bradykinin** and Substance P in the lungs, leading to their accumulation, which sensitizes cough receptors. * **C. Angioneurotic edema:** A rare but life-threatening side effect caused by the accumulation of bradykinin, leading to rapid swelling of the lips, tongue, and glottis. * **D. Skin rash:** Common with Captopril, often attributed to its sulfhydryl group, though it can occur with other ACEIs as well. **NEET-PG High-Yield Pearls:** * **Mnemonic for ACEI side effects (CAPTOPRIL):** **C**ough, **A**ngioedema, **P**roteinuria/ **P**otassium excess, **T**aste changes, **O**rthostatic hypotension, **P**regnancy (Teratogenic), **R**ash, **I**ncreased renin, **L**eukopenia. * **Teratogenicity:** ACEIs are contraindicated in pregnancy as they cause **fetal renal dysgenesis** and skull hypoplasia. * **Drug of Choice:** ACEIs are the first-line treatment for hypertension in patients with **Diabetes Mellitus** due to their renoprotective effects (reduction of efferent arteriolar resistance).

Q: With respect to ticlopidine, which of the following is true for clopidogrel?

Is less likely to cause neutropenia. Ticlopidine and clopidogrel are both **P2Y12 receptor antagonists** (thienopyridines) that inhibit ADP-induced platelet aggregation. While they share a similar mechanism of action, clopidogrel was developed as a second-generation agent specifically to improve the safety profile. **1. Why Option B is Correct:** The most significant clinical difference between the two is the risk of **hematological toxicity**. Ticlopidine is associated with life-threatening **neutropenia** (approximately 1% of patients) and agranulocytosis, requiring frequent CBC monitoring during the first three months of therapy [1]. Clopidogrel has a significantly lower incidence of neutropenia, making it the preferred clinical choice. **2. Why Incorrect Options are Wrong:** * **Option A:** Neither drug is typically associated with the formation of antiplatelet antibodies (this is more characteristic of Heparin-Induced Thrombocytopenia). * **Option C:** Clopidogrel does not inherently cause more severe bleeding than ticlopidine; their bleeding risks are comparable when used at standard therapeutic doses. * **Option D:** Both drugs are prodrugs that require hepatic activation (via CYP450). While clopidogrel is more potent and has a faster onset of action, the primary reason for its preference in clinical practice is its superior safety profile rather than a vastly "greater" antiplatelet ceiling. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Irreversible inhibition of P2Y12 ADP receptors, leading to decreased activation of the GPIIb/IIIa complex. * **Toxicity:** Ticlopidine causes neutropenia and **TTP** (Thrombotic Thrombocytopenic Purpura) [1]. Clopidogrel can also cause TTP, but it is much rarer. * **Pharmacogenetics:** Clopidogrel is a prodrug activated by **CYP2C19**. Patients who are "poor metabolizers" of this enzyme (or those taking **Omeprazole**, a CYP2C19 inhibitor) will have reduced antiplatelet efficacy [2].

Q: Which of the following antihypertensives is used in premenstrual syndrome?

Clonidine. **Explanation:** **Clonidine** is a centrally acting **$\alpha_2$-adrenergic agonist**. While primarily used as an antihypertensive, it is effective in managing **Premenstrual Syndrome (PMS)** and menopausal symptoms. The underlying medical concept involves its ability to reduce sympathetic outflow and modulate neuroendocrine fluctuations. Specifically, it helps alleviate vasomotor symptoms (hot flashes), irritability, and certain physical discomforts associated with the luteal phase of the menstrual cycle. **Analysis of Incorrect Options:** * **Hydralazine:** A direct-acting vasodilator used primarily in hypertensive emergencies and pregnancy-induced hypertension (PIH). It has no role in hormonal or symptomatic management of PMS. * **Losartan:** An Angiotensin II Receptor Blocker (ARB). It is used for chronic hypertension and diabetic nephropathy but does not cross the blood-brain barrier effectively or influence the symptoms of PMS. * **Amlodipine:** A Calcium Channel Blocker (CCB) used for hypertension and angina. It acts on peripheral vascular smooth muscle and lacks the central neuromodulatory effects required to treat PMS. **High-Yield Clinical Pearls for NEET-PG:** * **Other uses of Clonidine:** Opioid withdrawal (reduces sympathetic overactivity), ADHD, Tourette syndrome, and prophylaxis of migraine. * **Side Effects:** Sedation, mental depression, and **marked dryness of mouth**. * **Rebound Hypertension:** Sudden withdrawal of clonidine can lead to a hypertensive crisis due to a massive release of stored catecholamines. * **Drug of Choice for PMS:** While clonidine is an option, **SSRIs** (like Fluoxetine) are generally considered the first-line pharmacological treatment for severe PMS/PMDD.

Question 1

A drug is a classical example of pharmacological success but therapeutic failure due to the coronary steal phenomenon. Which drug is it?

Accepted Answer

Dipyridamole

Answer

Glyceryl trinitrate

Answer

Propranolol

Answer

Diltiazem

Question 2

A patient with cardiac disease should be advised to stop which of the following medications if experiencing a persistent cough?

Accepted Answer

Enalapril

Answer

Diltiazem

Answer

Aspirin

Answer

Clopidogrel

Question 3

Which of the following antiarrhythmic drugs does not cause Torsades de Pointes?

Accepted Answer

Lidocaine

Answer

Quinidine

Answer

Disopyramide

Answer

Procainamide

Question 4

Which one of the following is NOT true in relation to angiotensin converting enzyme (ACE) inhibitors?

Accepted Answer

Contraindicated in diabetic nephropathy

Answer

May cause hyperkalemia in diabetic patients

Answer

Contraindicated in pregnancy

Answer

NSAIDs may impair its hypotensive effect

Question 5

A sixteen-year-old girl is found to have paroxysmal attacks of rapid heart rate. What is the antiarrhythmic of choice in most cases of acute AV nodal tachycardia?

Accepted Answer

Adenosine

Answer

Amiodarone

Answer

Propranolol

Answer

Quinidine

Question 6

Which of the following is a venodilator?

Accepted Answer

Nitroprusside

Answer

Hydralazine

Answer

Minoxidil

Answer

Nifedipine

Question 7

Which of the following drugs can cause glucose intolerance?

Accepted Answer

All of the above

Answer

Thiazides

Answer

Propranolol

Answer

Furosemide

Question 8

Which one of the following is not an adverse effect of ACE inhibitors?

Accepted Answer

Hypokalemia

Answer

Cough

Answer

Angioneurotic edema

Answer

Skin rash

Question 9

With respect to ticlopidine, which of the following is true for clopidogrel?

Accepted Answer

Is less likely to cause neutropenia

Answer

Is more likely to cause formation of antiplatelet antibodies

Answer

Is more likely to cause severe bleeding

Answer

Has a greater antiplatelet effect

Question 10

Which of the following antihypertensives is used in premenstrual syndrome?

Accepted Answer

Clonidine

Answer

Hydralazine

Answer

Losartan

Answer

Amlodipine

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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