KMU Past Paper Practice

Question:

A 48-year-old man with episodic severe hypertension due to excess catecholamine release requires a short-acting α-adrenoceptor antagonist for rapid, reversible receptor blockade. Which drug best fits this requirement?

Options:

Correct Answer: Phentolamine

Explanation: Phentolamine produces short-acting, reversible non-selective α blockade, making it suitable when rapid control of catecholamine-mediated vasoconstriction is required.

Question:

A 67-year-old man has hypertension together with symptoms of benign prostatic hyperplasia. His physician chooses a drug that can reduce vascular resistance while also relaxing smooth muscle at the bladder outlet. Which drug is most appropriate?

Options:

Correct Answer: Doxazosin

Explanation: Doxazosin blocks α₁ receptors, producing both vascular smooth-muscle relaxation and relaxation of prostate and bladder-neck smooth muscle.

Question:

A patient taking an α₁-adrenoceptor antagonist for hypertension complains of persistent nasal stuffiness despite having no respiratory infection. Which pharmacological effect most likely accounts for this symptom?

Options:

Correct Answer: Dilatation of nasal mucosal vessels

Explanation: α₁ blockade reduces vascular tone in the nasal mucosa, producing vasodilation and congestion perceived as nasal stuffiness.

Question:

A 64-year-old man treated with an α-adrenoceptor antagonist reports that his urinary symptoms have improved but ejaculation has become abnormal. Which drug action most directly explains this adverse effect?

Options:

Correct Answer: Blockade of genitourinary α₁ receptors

Explanation: α₁ receptors participate in smooth-muscle contraction during emission and ejaculation; their blockade may therefore disturb normal ejaculatory function.

Question:

During revision, a student groups phenoxybenzamine and phentolamine together because both interfere with more than one alpha-receptor subtype. Which classification best describes this pair?

Options:

Correct Answer: Non-selective α antagonists

Explanation: Phenoxybenzamine and phentolamine block both α₁ and α₂ adrenoceptors and are therefore classified as non-selective alpha antagonists.

Question:

A hypertensive patient is prescribed a β₁-selective blocker that retains weak partial agonist activity at beta receptors. Which drug has this combination of properties?

Options:

Correct Answer: Acebutolol

Explanation: Acebutolol is relatively β₁ selective and has intrinsic sympathomimetic activity, meaning that it behaves as a partial agonist while blocking stronger catecholamine effects.

Question:

A patient with glaucoma also has a tendency to develop bronchospasm. The ophthalmologist prefers a topical beta blocker with relative β₁ selectivity rather than a non-selective agent. Which drug is most appropriate?

Options:

Correct Answer: Betaxolol

Explanation: Betaxolol is a β₁-selective beta blocker used topically in glaucoma and produces less bronchial β₂ blockade than non-selective ophthalmic agents.

Question:

A 58-year-old man recovering after myocardial infarction is prescribed a suitable beta blocker. Which pharmacological effect contributes most directly to protection from catecholamine-related cardiac complications?

Options:

Correct Answer: Reduced cardiac adrenergic stimulation

Explanation: Beta blockade reduces catecholamine-driven heart rate, workload and arrhythmogenic stimulation, which is beneficial after myocardial infarction.

Question:

A man with ischemic heart disease stops long-term propranolol abruptly because he feels well. Soon afterward, he develops marked palpitations and worsening chest discomfort. Which mechanism best explains this deterioration?

Options:

Correct Answer: Exaggerated response to endogenous catecholamines

Explanation: Abrupt withdrawal after chronic beta blockade can expose sensitized adrenergic pathways to catecholamines, producing rebound tachycardia and worsening ischemic symptoms.

Question:

A patient recently started on a beta blocker reports that climbing stairs now causes earlier fatigue despite adequate control of his blood pressure. Which physiological response has most likely been limited?

Options:

Correct Answer: Sympathetic increase in cardiac output during exercise

Explanation: Beta blockade limits the normal exercise-induced increases in heart rate and contractility, reducing the ability to raise cardiac output during exertion.

Question:

A 70-year-old man has a markedly prolonged atrioventricular conduction time on ECG and a slow ventricular rate. Which property of beta blockers makes their use particularly hazardous in this patient?

Options:

Correct Answer: Further slowing of AV nodal conduction

Explanation: Beta blockers reduce AV nodal conduction, so significant pre-existing conduction block may worsen and is an important contraindication.

Question:

A 72-year-old man presents with acute worsening heart failure, pulmonary congestion and poor peripheral perfusion. Starting a beta blocker at this stage may worsen his condition primarily through which action?

Options:

Correct Answer: Reducing myocardial contractility

Explanation: Acute beta blockade has a negative inotropic effect and can worsen pump failure in an unstable patient with acute decompensated heart failure.

Question:

A middle-aged patient with pre-existing dyslipidemia is being considered for long-term beta-blocker therapy. Which metabolic change is a recognized limitation of some drugs in this class?

Options:

Correct Answer: Higher triglycerides with lower HDL cholesterol

Explanation: Some beta blockers may unfavorably alter lipid metabolism by increasing triglycerides and reducing HDL cholesterol, which matters in patients with dyslipidemia.

Question:

A patient with markedly elevated arterial pressure requires an agent that decreases peripheral resistance through α₁ blockade while simultaneously limiting sympathetic cardiac effects through beta blockade. Which drug is most appropriate?

Options:

Correct Answer: Labetalol

Explanation: Labetalol combines α₁-mediated vasodilation with beta blockade and is useful in hypertension, particularly when effective blood-pressure control is required.

Question:

A patient with significant chronic liver dysfunction is prescribed propranolol. Which pharmacokinetic feature makes alteration of drug exposure particularly relevant in this patient?

Options:

Correct Answer: Extensive metabolism in the liver

Explanation: Propranolol undergoes extensive hepatic metabolism, so impaired liver function can alter its metabolism and systemic exposure.

Question:

A pharmacology student traces the disposition of propranolol after it has undergone hepatic biotransformation. Through which route are its metabolites mainly eliminated?

Options:

Correct Answer: Kidneys

Explanation: Propranolol is extensively metabolized in the liver, after which its metabolites are eliminated mainly through the kidneys.

Question:

An ophthalmic beta blocker used to lower intraocular pressure also possesses intrinsic sympathomimetic activity. Which drug best matches these properties?

Options:

Correct Answer: Carteolol

Explanation: Carteolol is an ophthalmic beta blocker that can reduce aqueous humor formation and is also among the beta blockers possessing intrinsic sympathomimetic activity.

Question:

A clinically stable patient with chronic systolic heart failure requires a β₁-selective blocker with established long-term usefulness in this condition. Which drug is an appropriate choice?

Options:

Correct Answer: Long-acting metoprolol

Explanation: Appropriate long-acting metoprolol is among the beta blockers with established benefit in clinically stable chronic heart failure.

Question:

During a discussion of beta-receptor pharmacology, a student is asked to identify a pair of clinically used beta blockers known to demonstrate inverse agonist behavior rather than partial agonist activity. Which pair is most appropriate?

Options:

Correct Answer: Metoprolol and carvedilol

Explanation: Metoprolol and carvedilol are examples of beta blockers demonstrating inverse agonist behavior, whereas pindolol and acebutolol are associated with partial agonist activity.

Question:

Two patients require mixed adrenoceptor antagonists. One needs effective treatment of markedly elevated blood pressure, while the other has clinically stable chronic heart failure. Which drug pairing best matches these respective clinical priorities?

Options:

Correct Answer: Labetalol followed by carvedilol

Explanation: Labetalol is particularly useful for hypertension, while carvedilol is a mixed α₁/β antagonist with established benefit in stable chronic heart failure.