Pharmacology Case Studies: 150 Expert-Level
Questions with Rationales
2025/2026
1. A 65-year-old male with hypertension and chronic kidney disease
presents with edema. He is prescribed furosemide. Which
electrolyte imbalance is most likely?
Potassium depletion
Rationale: Loop diuretics like furosemide increase renal excretion
of potassium, sodium, and chloride, leading to hypokalemia.
2. A patient taking warfarin presents with bruising and nosebleeds.
Which lab value would most likely be elevated?
INR (International Normalized Ratio)
Rationale: Warfarin inhibits vitamin K–dependent clotting factors,
prolonging PT/INR and increasing bleeding risk.
3. A 55-year-old diabetic patient is prescribed metformin. Which
adverse effect should be monitored?
Lactic acidosis
Rationale: Metformin rarely causes lactic acidosis, particularly in
patients with renal impairment or hypoperfusion.
4. A patient with asthma is prescribed albuterol. What is the primary
mechanism of action?
Beta-2 adrenergic receptor agonist
Rationale: Albuterol stimulates beta-2 receptors in bronchial
smooth muscle, causing bronchodilation.
5. A 70-year-old patient on digoxin presents with nausea, visual
disturbances, and bradycardia. What is the most likely cause?
Digoxin toxicity
, Rationale: Symptoms of digoxin toxicity include gastrointestinal
upset, visual changes (yellow/green halos), and cardiac
arrhythmias.
6. A patient with bacterial pneumonia is prescribed ceftriaxone.
Which statement about ceftriaxone is correct?
It is a third-generation cephalosporin with broad-spectrum
activity
Rationale: Third-generation cephalosporins are effective against
Gram-negative organisms and some Gram-positive bacteria.
7. A patient on long-term corticosteroid therapy develops weight
gain, hyperglycemia, and buffalo hump. Which condition is
indicated?
Cushing syndrome
Rationale: Chronic glucocorticoid therapy can induce Cushingoid
features due to excess corticosteroid exposure.
8. A patient presents with hypertensive crisis. Which
antihypertensive is contraindicated with MAO inhibitors?
Methyldopa
Rationale: MAO inhibitors interact with many antihypertensives;
hypertensive crisis can result due to excessive sympathetic activity.
9. A patient with chronic heart failure is prescribed spironolactone.
What is a significant adverse effect to monitor?
Hyperkalemia
Rationale: Spironolactone is a potassium-sparing diuretic that
inhibits aldosterone, increasing serum potassium.
10. A patient receiving insulin for type 1 diabetes develops
sweating, confusion, and palpitations. What is the immediate
intervention?
, Administer oral glucose if conscious
Rationale: Hypoglycemia is treated promptly with oral glucose if
the patient can safely swallow, or IV dextrose if unconscious.
11. A patient taking levothyroxine reports palpitations and
insomnia. What is the likely cause?
Excess thyroid hormone
Rationale: Over-replacement with levothyroxine can lead to
hyperthyroid symptoms, including tachycardia and nervousness.
12. A patient with chronic pain is prescribed morphine. What is
the most concerning adverse effect?
Respiratory depression
Rationale: Opioids can depress the central respiratory drive;
monitoring for respiratory rate and oxygen saturation is essential.
13. A patient is prescribed aminoglycosides for a severe
infection. What lab should be monitored?
Serum creatinine
Rationale: Aminoglycosides are nephrotoxic; renal function
monitoring is required to prevent kidney damage.
14. A patient presents with hypotension after taking
nitroglycerin. What is the mechanism?
Vasodilation via nitric oxide–mediated smooth muscle relaxation
Rationale: Nitroglycerin releases nitric oxide, activating guanylate
cyclase, leading to smooth muscle relaxation and vasodilation.
15. A patient taking phenytoin develops gum hypertrophy. What
is the mechanism?
Drug-induced fibroblast proliferation in gingival tissue
Rationale: Phenytoin stimulates gingival fibroblasts, causing gum
overgrowth, especially with poor oral hygiene.
Questions with Rationales
2025/2026
1. A 65-year-old male with hypertension and chronic kidney disease
presents with edema. He is prescribed furosemide. Which
electrolyte imbalance is most likely?
Potassium depletion
Rationale: Loop diuretics like furosemide increase renal excretion
of potassium, sodium, and chloride, leading to hypokalemia.
2. A patient taking warfarin presents with bruising and nosebleeds.
Which lab value would most likely be elevated?
INR (International Normalized Ratio)
Rationale: Warfarin inhibits vitamin K–dependent clotting factors,
prolonging PT/INR and increasing bleeding risk.
3. A 55-year-old diabetic patient is prescribed metformin. Which
adverse effect should be monitored?
Lactic acidosis
Rationale: Metformin rarely causes lactic acidosis, particularly in
patients with renal impairment or hypoperfusion.
4. A patient with asthma is prescribed albuterol. What is the primary
mechanism of action?
Beta-2 adrenergic receptor agonist
Rationale: Albuterol stimulates beta-2 receptors in bronchial
smooth muscle, causing bronchodilation.
5. A 70-year-old patient on digoxin presents with nausea, visual
disturbances, and bradycardia. What is the most likely cause?
Digoxin toxicity
, Rationale: Symptoms of digoxin toxicity include gastrointestinal
upset, visual changes (yellow/green halos), and cardiac
arrhythmias.
6. A patient with bacterial pneumonia is prescribed ceftriaxone.
Which statement about ceftriaxone is correct?
It is a third-generation cephalosporin with broad-spectrum
activity
Rationale: Third-generation cephalosporins are effective against
Gram-negative organisms and some Gram-positive bacteria.
7. A patient on long-term corticosteroid therapy develops weight
gain, hyperglycemia, and buffalo hump. Which condition is
indicated?
Cushing syndrome
Rationale: Chronic glucocorticoid therapy can induce Cushingoid
features due to excess corticosteroid exposure.
8. A patient presents with hypertensive crisis. Which
antihypertensive is contraindicated with MAO inhibitors?
Methyldopa
Rationale: MAO inhibitors interact with many antihypertensives;
hypertensive crisis can result due to excessive sympathetic activity.
9. A patient with chronic heart failure is prescribed spironolactone.
What is a significant adverse effect to monitor?
Hyperkalemia
Rationale: Spironolactone is a potassium-sparing diuretic that
inhibits aldosterone, increasing serum potassium.
10. A patient receiving insulin for type 1 diabetes develops
sweating, confusion, and palpitations. What is the immediate
intervention?
, Administer oral glucose if conscious
Rationale: Hypoglycemia is treated promptly with oral glucose if
the patient can safely swallow, or IV dextrose if unconscious.
11. A patient taking levothyroxine reports palpitations and
insomnia. What is the likely cause?
Excess thyroid hormone
Rationale: Over-replacement with levothyroxine can lead to
hyperthyroid symptoms, including tachycardia and nervousness.
12. A patient with chronic pain is prescribed morphine. What is
the most concerning adverse effect?
Respiratory depression
Rationale: Opioids can depress the central respiratory drive;
monitoring for respiratory rate and oxygen saturation is essential.
13. A patient is prescribed aminoglycosides for a severe
infection. What lab should be monitored?
Serum creatinine
Rationale: Aminoglycosides are nephrotoxic; renal function
monitoring is required to prevent kidney damage.
14. A patient presents with hypotension after taking
nitroglycerin. What is the mechanism?
Vasodilation via nitric oxide–mediated smooth muscle relaxation
Rationale: Nitroglycerin releases nitric oxide, activating guanylate
cyclase, leading to smooth muscle relaxation and vasodilation.
15. A patient taking phenytoin develops gum hypertrophy. What
is the mechanism?
Drug-induced fibroblast proliferation in gingival tissue
Rationale: Phenytoin stimulates gingival fibroblasts, causing gum
overgrowth, especially with poor oral hygiene.
